Monday, November 20, 2017

Brewing Bières de Gade (1850-1910)

Following up on this blog post giving background info on Bière de Garde and French brewing around 1900, this post gets into the brewing side of historic Bière de Garde. As noted in the background post, these beers are distinct from the modern northern French beers of the same name. As a brief comment on the modern side, I learned recently from Daniel Thiriez of Brasserie Thiriez that there is a new (well, ~1 year old) French law regarding what can be called a Bière de Garde - the beers now must be aged a minimum of 21 days after primary. We agreed that this law seems to be a bit toothless and quite broad, as there is no recipe restriction, etc. And 21 days is a far cry from the 6+ months of aging for Bière de Garde from around 1900.

Bière de Garde advertisement from the early 1900s.
From the collection of D. Thiriez.
The information for this post is a synthesis of 9 texts from 1850 to the early 1900s. These texts present a view from more established breweries, and spanning the time from the height of Bière de Garde to near when the original long-aged mixed culture versions disappeared. While each of the texts has small differences from the others, the general nature of the beer remains the same - a roughly amber colored beer of mixed fermentation with a moderate hopping and which is allowed to become acidic and vinous over 6+ months of aging.

Ingredients:
The grist composition of Bière de Garde was 100% malted barley which, for the time, was kilned using older methods. Direct heat was used and that the malt came out slightly toward amber. I think something along the lines of a continental European Pale Ale malt is about right given the descriptions of the final beer color and the process. The recommended barley was the Escourgeon, or winter 6-row barley. This was the common grain for much the area (across Belgium you often see the same recommendation) and it could be a bit of a sharp or coarse malt. Escourgeon had more polyphenols and higher nitrogen levels, which would help to develop more melanoidin compounds in kilning and boiling. This sort of malt wasn't great for softer or quicker turnaround beers, but it was well suited for aged beers.

Hops for Bière de Garde were primarily coming from the Nord region or Belgium. These hops were of more standard quality. This may present a bit of a challenge to the modern brewer, but French landrace hops may be a good place to start. Some sources also mention a portion of higher quality hops coming from Bavaria, Bohemia, or other regions of France, so this gives modern brewers some more options.

Yeast was pitched for Bière de Garde, and based on the descriptions of the final beers it was a mixed culture involving at least Brettanomyces and lactic acid bacteria in addition to Saccharomyces. Figuier, quoting Müller (1873), notes that Bière de Garde, and in general the beers of this region, had a vinous quality and that this quality was sought by locals.

General Specifications
Bière de Garde is described as an golden-amber or brown beer (sometimes both by the same source, suggesting that "brown" may have been used more generally or encompassed a wider range than it does now). Either way, from this I suspect the beers were generally not toward the darker side of brown, and a pale amber may be a better description for the modern brewer/beer drinker. The paler side of amber seems to fit better with the above photo. Though I'll note that the original of that print was from 1930, and therefore after Bière de Garde as discussed here had mostly (if not fully) vanished.

This table (below), modified slightly from a similar one posted a couple weeks ago on the blog's FB page, shows the parameters of ~1900 Bière de Garde alongside 1970s & modern lambic and geuze as well as modern Flanders acidic ales. Taking these 5 examples of Bière de Garde, the OG that one could expect around 1900 was roughly 1.045. This sounds a little low to me, so I wouldn't be surprised if gravities that were a bit higher (~1.050-1.055) were also brewed. But I haven't seen other gravities listed so far. With a very high attenuation, the alcohol of these examples generally comes out to around 6% ABV.

The acidity of the beers was fairly high, both in lactic and acetic acidity. On the whole the acid profiles compare well with Flanders acidic ales before they are blended back with younger beer for packaging, though BdG was a bit lower in lactic acid than these Flanders beers. And the acidity also compares well with more sharp lambics, but when averaging across multiple producers from the 1970s, ~1900 BdG is higher in both lactic and acetic acid.

A comparison of ~1900 Bière de Garde with some modern aged acidic beers.

Brewing Process
Mashing: Bière de Garde used a type of turbid mashing. Although only a few turbid mash schedules are known today, and only for a small range of beers, different schedules of turbid mashing were employed for a wide range of beers in Belgium and northern France. And there were many more versions of turbid mashing than remain in modern brewing (though even today there are still differences among lambic brewers about the specific rests, number of turbid pulls, and when the turbid wort is added back). The different Bière de Garde texts that I've seen all more or less describe the same sort of mash, with 3 temperature rests and one turbid pull:

-An initial infusion is conducted. Some texts have this rest temperature quite cool (25-35 C, some even lower than this) and others have it higher, in the protein conversion range.
-After the first rest, the wort is drained off and heated to a boil in a secondary boil kettle. This is the one turbid pull used in Bière de Garde mashing.
-Hot water (somewhere from 80 C to boiling) is added back to the grain bed to raise the temperature to the cooler end of the saccharification range. The mash rests here for a while.
-Wort is extracted and transferred to the primary boil kettle. Now the turbid wort which has been boiled comes back to the grain, and an additional saccharification step is now carried out with this wort.
-After the second saccharification this wort is combined with the earlier mash runnings in the primary boil kettle.
-The grain bed is sparged, more or less as normal, though much of this wort is used for table beers rather than Bière de Garde.

Here are a couple mash schemes from historic texts. First is a scheme based on the information in Bauby & Fournier (1868), taking into account the mashing that Bauby & Fournier report, the modifications they suggest, and filling in some gaps with reasoning and similar general schemes described by other sources. The second is a reproduction of the mashing scheme I presented in this blog post, which originally comes from Evans (1905). A couple of sources I looked at have the initial rest closer to 50 C rather than the cool starts of both of these mashes. But otherwise these other mashes follow a similar remaining process to these two. Finally, for reading the figures below, blue arrows represent transfer of liquid (removal of turbid wort, infusions, collecting final wort).

A mashing scheme based off of Bauby & Fournier (1868).
There are a couple general things to keep in mind with these mashing schemes. First, these mashes reflect non-modern conditions. Rest times could probably be shortened a bit if you wanted to try these yourself. Also, with the sort of equipment used in these breweries at this time, there was a much larger heat loss to the vessels than with modern equipment when raising the mash temperature. Additionally, it would not be uncommon to have an open topped mash tun, which would also lose a good deal of heat. Jean-Louis Dits of Brasserie à Vapeur has such a mash tun, and he reported temperature drops of up to 2 C per 30 minutes (see this post for more info about their mashing). So if you want to try one of these mashes yourself, you may want to lower the infusion temps to hit your targets and keep extra cold water around in case you overshoot. Finally, not everything is specified with these mashes to the extent that I would like (especially in the mash based on Bauby & Fournier). I have tried to fill in the gaps with what is reasonable given the mash process up to that point, expected heat loss, and what the wort would need to be like. And I have tried to present the remaining uncertainty to these assumptions.

The mashing scheme presented in Evans (1905).

Boiling: Bière de Garde underwent a long boiling. The sources agree on at least a 5 hour boil, with many mentioning boils lasting up to 8-10 hours. Considering this, the gravity is fairly moderate at around 1.040-1.050. The English brewers discussing the boil in Evans (1905) also note that they were surprised that the boil did not darken the beers as much as they expected.

Hopping rates were around 4-5 g/L (0.53-0.67 oz/gal), with some sources mentioning rates slightly above and below this. Some sources say that hops were added right at the start of the boil while others say hops were "only" boiled for a couple hours. So either way hops underwent a long boil of multiple hours. Some hops, especially if higher quality hops were used, may have been reserved for later in the boil. But overall this isn't discussed much in these texts

At the end of the boil the beers were cooled in coolships.

Fermentation: As noted above, Bière de Garde was pitched with a mixed culture, though at a lower rate than would have been common for most beers at the time. Fermentation began somewhere from around 20-25 C. Some later sources note the temperature may have started a bit cooler (~17-21 C). The beers were fermented in casks, generally the same casks as used for transport, and active fermentation took around 3 days. Following the primary fermentation, the beers were aged for around 6 months or more, during which time the beers developed acidity and vinous character.

Closing thoughts:
Having discussed BdG recipe and process, I think it is noteworthy that the descriptions of French Bière de Garde are quite similar to the descriptions of Saison in Belgian sources from around the same time. Suggested malts, mashing process, hops, boiling time, etc. are in general basically the same for these two beers. This is not surprising given that the Nord department borders the Hainaut province and that the beers share similar origin lore, but I think it is worth pointing out anyway.

Something to think of when
considering historic Bière de Garde?
Finally, I think it may be helpful to contextualize historic Bière de Garde by considering Cantillon's Iris. Perhaps this is a bit of a tired reference. When considering the above BdG-Saison comparison, I know I frequently say something to this effect and it is also in the De Baets chapter on Saison history in Farmhouse Ales. But I think the similarities are sufficient to bring it up again. Both are 100% malted barley (even more so - malt of about the right color) and also turbid mashed. The hopping rates are similar (though BdG was hopped a bit more and Iris is dry hopped). They both have a long boil and then are cooled in a coolship. Of course there are the important differences that Iris is spontaneously fermented while BdG was pitched with a mixed culture, Iris uses some aged hops, and Iris is aged longer. But still I think Iris probably falls closer to ~1900 BdG than many other modern beers would.

This wraps up a historic Bière de Garde brewday. Hopefully you found that informative, and it helped to differentiate the modern and historic (1850-1910) beers using this name. Here are links to other posts on the blog discussing Bière de Garde, both of which are also linked in the text above:

-Thoughts on Evans, 1905
-Introductory thoughts on BdG


Sources:
Lacambre (1851). Traité Complet de le Fabrication des Bières...
Bauby & Fournier (1868). Guide Raisonné de la Fabrication de la Bière.
Figuier (sometime in the 1870s, I'm not sure of the exact date). Les Merveilles de l'Industrtie...
Cartuyvels & Stammer (1879). Traité Complet Théorique et Pratique de le Fabrication de la Bière et du Malt
Boulin (1889). Manuel Pratique de la Fabrication de la Bière.
Moreau & Levy (1905). Traité Complet de le Fabrication des Bières...
Evans (1905). The Beers and Brewing Systems of Northern France.
Petit Journal du Brasseur (1910).
Mulo (I don't know the year). Brasseur ou Art de Faire Toutes Sortes de Bières.
Thanks also to Daniel Thiriez and Yvan De Baets for conversations that helped with organizing my thoughts about these beers.

Wednesday, October 25, 2017

Introductory thoughts on Bière de Garde

For the past couple years I have been somewhat passively researching Bière de Garde and I think the time has come for me to start being a bit more active about putting this info together into blog posts. Before getting into the brewing side I wanted to start with this an introductory/general post to address terminology and the setting for the beer. For clarity throughout this post, I'll use capitalized "Bière de Garde" to refer to the specific family of beers from the north of France and I'll use lower case "bière de garde" when using the term to more generally refer to aged beers. If this doesn't make sense, it should shortly.

The term Bière de Garde
A question regarding brewing a bière de garde from Ghent.
(Petit Journal du Brasseur, 1901).
Discussion of bière de garde from Augsburg and Munich, Lacambre (1851).
I find Bière de Garde to be one of the trickier families of beer to discuss based on the wide range of what this name can mean. To the non-Francophone beer world this term likely refers fairly unambiguously to a distinct (though still stylistically open) category of beers from the Nord and Pas de Calais departments of northern France. But the non-Francophone beer world might not be as familiar with this term to apply generally to a diverse category of aged beers, using the term for its literal meaning (beers for keeping/storage, or since this part has been done already by the brewer, beers that have been kept). The historic Belgian brewing literature regularly uses this term to discuss general beers designed to be aged. And these beers could cover quite a range of strengths, ingredients, and brewing styles. In the modern world I think bière de garde is used less generally, but when looking through the historic texts the French Bières de Garde are definitely in the minority of the uses of this term.

Just as the French-language brewing literature may use the term bière de garde to refer to beers unrelated to historic Bières de Garde, the modern beers bearing this name as a category are also fairly unrelated to the historic category. There is a discontinuity not only temporally between the historic mixed culture Bières de Garde that were found until the early 1900s and the modern range of beers bearing this name, but also in process and ingredients. For the rest of this post I'll generally be discussing historic Bières de Garde, focusing on the period between industrialization of breweries and when the historic versions disappeared in the early 1900s. For those interested in the rebirth of the name and the modern iterations, Farmhouse Ales (by Markowski) and The Beers of Northern France by Rigley and Woods give a good idea of the story and the range of producers. The former should already at least be on the list of any Anglophone brewer interested in Bière de Garde and saison, if not already read and re-read multiple times. While the latter is a bit dated, it can be found (at least now) for ~5 USD / EUR. It is certainly worth that if you're interested in French beer.

Recommended reading for modern Bière de Garde.
Brewing in France before the 1900s and brewers of Bière de Garde
While France may not have had always the beer focus of some of its neighbors, many distinct regional beers were brewed in the 1800s and earlier. Around 1850, Lacambre (Traite Complet de le Fabrication des Bières..., 1851) describes distinct regional ales from Paris, Strasbourg and Lyon in addition to the beers of Lille. I should note that Bière de Garde is generally discussed under the category of beers of Lille in the historic texts I've seen (Lille is the most prominent city of the Nord department). I am combining Nord and Pas-de-Calais for this discussion as modern Bière de Garde brewers can be found in both departments. But most of the historic documents I've seen mention Lille, and possibly the Nord in general, as the region for Bière de Garde without addressing Pas-de-Calais.

This diversity of regional beers seems to have changed quickly, as Figuier (Les Merveilles de l'Industrie, published in the 1870s) notes that Paris had switched rapidly to lager brewing starting in the late 1860s, modeling their beers after those from Bavaria and Vienna. During this time the brewers of Lille continued to produce their beers of top fermentation - these including Bière de Garde as well as an ordinary brown beer (which was served young) and table beers. In addition, some brewers produced a white beer (which I've written about here), though this was not very common.

A map showing the he Nord and Pas-de-Calais departments of
Northern France, western Belgium and some larger cities.
The resilience of the north, though strong, was unfortunately not enough to preserve these beers. Evans (1905) and Moreau and Levy (also 1905) both note that few regions of France were still producing top fermentation beers in 1905. And Evans notes that Bière de Garde was rapidly becoming less popular, having fallen from 50% of the consumption of Lille in 1900 to less than 20% in 1905.  With Bière de Garde already on the back foot, WWI was pretty much the end of the style. As I've written about a bit in this post, the devastation the region faced and the way this put additional pressure on breweries (loss of life, loss of equipment, insufficient crops to maintain production, etc.) resulted in a significant loss of breweries and the regional beer identity compared to before the war. This basically signals the end of traditional Bière de Garde production.

The table below shows brewing trends in the north of France in the early 1900s (the number of breweries and production volume, in degrees-hectoliters). This is presented for both the Nord department alone as well as the 5 northern departments of France that were more prominent beers regions (including Nord and Pas-de-Calais). While the date coverage is a bit spotty, there is a clear difference between the early 1900s (before WWI), where production and brewery numbers seem fairly stable and the 1930s. Other 1930s data as presented in Petit Journal du Brasseur 1939 are generally similar, though a decline in the number of breweries and some variability in total production are seen during the 1930s. 1939 was chosen for this comparison and it included both the number of breweries and the production volume for the same year.

Some quick data on the breweries and production levels in Northern France in the early 1900s.
The Bière de Garde revival, with distinctly different beers from the original Bières de Garde, begins roughly 10-50 years after this, depending on who you credit. Jenlain claims to have been the first among the new brewers to use the name Bière de Garde for their ale aged a couple weeks in tanks in the 1920s. Castelain employed the title in the 1970s for their lager CH'TI, also aged for weeks rather than months. It was not until around the 1970s and later that the name caught on to mean a new category of northern French beers.

General characteristics of historic Bière de Garde
A few points are clear about the general nature of historic Bières de Garde. They were turbid mashed, as is discussed in this blog post. Additionally the beers were top fermentation mixed culture beers. And, given that they were aged for many months, they had some chance to express this character. This is in strong contrast to modern versions, where the beers may be lagers or fairly neutral ales (as well as ales with a bit more fermentation character) which are generally aged a couple additional weeks.

This is sort of a strange contrast between the two Bières de Garde (along with some process differences that I'll get into in a future post), and makes them in effect two unrelated products. I think using the term bière de garde to refer to a beer with a bit more aging in the process is fine. And the modern use of the term does denote a specific category of beers (varied though that category may be, and although the aging is fairly short). But I think making a tie between the historic and modern beers of this name is tenuous at best. Perhaps it is better to brew the beer you like, call it something that makes sense and communicates what it is, and let the beer be just a beer without trying to invoke the historic lore of a beer brewed with fundamentally different ingredients and substantially different methods on different equipment.

Closing
Alright, so this gives a bit of an intro into Bière de Garde - where it came from, when it was produced and differences between the historic and modern versions. I'm working on synthesizing recipes and process to put together a post detailing brewing these beers. I've already let a bit of that info out in the form of this post on the blog's facebook page, showing the OG, FG and acid profiles of Bière de Garde from around 1900 as well as modern lambic and Flanders acidic ale. Hopefully I'll have a brewing process/recipe-focused post within the next couple weeks.

Monday, August 28, 2017

Spontaneous fermentation barrel fill

This post details the first spontaneous beer I have fermenting in oak. It is in a 225 L / 60 gallon barrel that I co-own with some friends, and so far it is progressing nicely. We filled this barrel with one big brew day - a turbid mashed brew taking inspiration from lambic production - using a bunch of our homebrew equipment pooled together.

I'll focus mostly on our decision taking for this approach to the barrel rather than a solera-type approach and cleaning the barrel, but I'll also include more typical brewday stuff (our plan, recipe, process, etc).

The barrel needing a bit of touching up, accomplished here
with a heat gun, beeswax and something like a putty knife.
The barrel
I've mentioned the origins of this barrel in this blog post. Since November 2014 this barrel has been full of a homebrew solera-type project. The initial fill was a saison with brett and Lactobacillus. After about 7 months we pulled off ~1/3 and re-filled with young (<1 month old) beer that was turbid mashed, open cooled and then pitched with various cultures (dregs, ambient wild microbes and lab cultures). A second partial empty and refill was done 14 months later, again with lambic-inspired young beer (and one portion was spontaneous this time).

Since the initial fill, we felt that the beer wasn't really progressing the way we wanted. The end goal was something lambic-inspired and the group that shares the barrel has had a growing interest in spontaneous fermentation. But the partial re-fills with young beer weren't really pushing us in that direction as much as we liked. The beers coming out had increasing acidity, approaching levels beyond our goals for a balanced product, and the flavor complexity wasn't really developing as we wanted. Maybe this is influenced by the pretty strong presence of saison still in the barrel. Also, with the pitched cultures already present in the barrel we felt that we may have been preferentially feeding a subset of the organisms active over the course of spontaneous fermentation rather than getting the expression of a more thorough set of microbes over the course of fermentation.

The barrel waiting to be filled the morning after the brew day.
To be clear the beer coming from the barrel was fine. It was pleasant to drink and I've used it in blends (here for example). But the beer was lacking complexity, and we were looking for something more from the investment of time and the potential that we knew the barrel had. Our slightly underwhelming experience is not to say that a solera system inherently won't produce the beer we were looking for. Though I do think perhaps it is better suited for certain styles, at least as it is practiced by homebrewers. And maybe our goals weren't aligned with the strengths of a solera-type system. The typical homebrew solera is a bit different from the traditional solera system (for example as used in sherry), where a multiple barrel system is employed. With this system, refilling is accomplished using the next oldest product when the oldest product is partially removed. This continues up the line such that progressively younger but already aged product does the refilling for most of the levels. On the homebrew side when it can frequently be wort or rather young beer and a one-vessel system, the refilling may not done with an aged product. That's certainly the way we did it at least. And our experience may have been better if we refilled with 6+ month old beer rather than <1 month old beer or wort.

About 25-50% of the pooled gear...
Anyway, this specific barrel wasn't on our ideal track, so we were looking to completely empty, clean, and re-fill either way. With that in mind, along with the selective feeding idea and the end goal of spontaneous fermentation, we decided to step away from the homebrew solera approach and opted for a complete fill from one brew day, open cooled at one spot overnight, and racked in to the barrel without pitching any cultures.

Planning the brew day
Completely filling a 225 L wine barrel on homebrew gear is not an easy task. We've done this before doing 3 brews in series. But that was with more simple infusion mashes and a shorter boil. With the long boils and intensive mashing process we were going for this time, we decided on brewing in parallel. If getting together with 3 of your friends to brew about 250-300 L of wort in order to have at least 225 L after overnight cooling sounds like a good idea to you, then I guess there's a few of us out there. If it sounds like a terrible idea, there's probably a good deal more in your camp. In all honesty it is probably a bit of both.

This much grain means a lot of stirring of thick mashes...
We started the planning with a list of the equipment we had available to make sure we had the physical capacity to hold and heat that much liquid. We were bringing together 4 brew systems using different methods of heating and mashing (electric BIAB, electric w/ false bottom, stovetop BIAB and propane w/ false bottom), which required some shuffling to make it all work out. But with this and with the additional miscellaneous gear we had, the brewday could go forward.

We split that gear into roughly 3 brews. Or at least 3 mashes, as some brews may require multiple boils. We designed these brews so they could be treated as more or less independent, but flexibility with this was key on brew day. In general things went as well as they did because we had enough people to problem solve and/or make runs for additional supplies as needed during the brew.

2 of the 3 propane boil kettles
By the end of April 2017, after weeks of planning and sending drafts with all of our equipment capacity and shifting vessels around to try to produce enough wort, we had everything sorted for the brew day:

-We planned for 3 mashes at the same time with one large electric kettle to heat the necessary strike and infusion water and one kettle for the combined turbid wort.
-The boil would be split into ~5 kettles, as needed. As the volume dropped during the boil, and as we cleaned larger pots from the mash, we could combine into 4 total.
-Our cooling plan was to use the bottom half of a Blichmann  conical fermenter and two of the boil kettles.

This gave us an estimated cooling capacity of around 285 L / 75 gal (we had to guess at the volume of the conical), which should be sufficient with evaporative and trub/hop losses to get near to the target of filling the barrel.

The two electric boils and the extra extractor fan.

The brew day
We used about 60% locally grown and malted barley and 40% soft white wheat. Our turbid mash had 4 rest steps (dough in, protein, cool saccharification and warm saccharification) plus a mash out and 2 turbid pulls. We generally followed the Cantillon turbid mashing process (see MTF and lambic.info for more specifics here, see also Wild Brews by Jeff Sparrow and this Funk Factory writeup). The snags on the mash side were trying to evenly split sparge water across mashes of different sizes and different types of mashes (which inherently drain at different rates). This was compounded by stuck sparges on the largest of the mashes due to the high load of difficult grains.

While a benefit of turbid mashing is that it allows for overloading mash tuns, both in terms of fill level and in terms of proper conversion for good runoff, traditional Belgian mash tuns for this are more tuna can-shaped than our soup can-shaped tuns. So for the same volume our grain bed ends up comparatively deeper. This also made mixing difficult, as shown above, which could have resulted in worse conversion of the mash and could have contributed to the stuck sparge. Anyway, that was sorted out well enough, but it took a bit more time and made the splitting of sparge water (i.e. tying not to over-sparge some mashes and under-sparge others) trickier.

Cooling vessels 2 & 3.

Cooling vessel #1

We planned for a 3 hour boil and were fine with topping up the boil with water as needed. We wanted to fill the barrel completely so we were happy to take a small loss in OG if it meant a full barrel. We were hopping at a rate of around 3.8 g/l (based on the target end of boil volume) with aged pellets from hops direct and homegrown aged whole hops. We added these at the start of the boil. With the two electric systems going inside we needed to bring in an industrial extraction fan (in addition to the normal kitchen hood already active) to properly remove the moisture.

We left these beers to cool overnight. The nighttime low for the area on that night was just under 8 C (about 46F). Wort from the two electric boil kettles was transferred to the lower part of the conical fermenter, and therefore this wort was removed from the hops. The other two pots of wort were topped up with remaining electric wort and left to cool on their own, so these still had at least most of their hops in contact. The wort remained to cool for a total of about 16 hours before being transferred into the barrel and the wort temperatures on the morning after cooling were 12 and 14.5 C (53.5 and 58 F) in the two boil kettles. So the temperatures, both ambient and wort, worked out great.


Emptying the barrel.

Barrel cleaning
We had decided to empty the barrel on the same day as the brew day. We figured there would be enough down time during the ~3 hour boil to allow for this, and we didn't want to store the barrel dry or use any sort of storage solution if it could be avoided (as both of those would require extra work rinsing and/or swelling before we could use it). This did add the challenge of needing enough empty carboys to hold a full barrel, and transporting those as well as all the gear, but at least we didn't need any carboys for the wort going in.

We did this racking with a pressurized racking cane built with help from the engineer of the group. The basics of the cane follows this post on A Beer Diary, but with a cross instead of a plus to allow for a pressure relief valve (and this is a 1/2" cane rather than 3/8"). See also this FB thread on MTF. I'm behind on making use of the beer that came out, but that's another story.

With the boil done (clearing up some outside space) and the barrel empty, we could turn out attention to cleaning the barrel. We wanted to do a fairly thorough clean for a fresh start. Our strategy was primarily 2 parts - a prolonged spraying followed by steaming.

The barrel was sprayed out for a long time
We started the spraying with hot water at a laundry sink but we quickly realized our spraying goals were going to be better served by moving outside for the cleaning. The barrel was sprayed out with cool water until the water ran clear and tasted pretty neutral. This spraying also included some vigorous sloshing and rolling for good measure. This took a long time. I don't have notes on exactly how long, but all together it was 30 minutes+ of spraying, sloshing, dumping and re-spraying. Then the barrel was visually inspected and trouble areas were targeted until it all looked good. I spent much of this time becoming increasingly less dry...

Our spraying out also included wanting to spray the inside top of the barrel, but we weren't able to easily reach that. We were able to get around this by bending a standard racking cane (after first softening it with a heat gun) to about a 30° angle, or perhaps a bit smaller, and cutting the extra length of the cane off. This allowed the end to fit into the barrel and direct the spray back toward the top.

Now we had a visually clean barrel, but we had been using cold water which wouldn't do much to knock back the microbes that we didn't physically remove. For this we had a steaming plan. Steaming on a home scale can be a bit trickier. After trying to come up with some good way to do this, the engineer of the group came to the rescue with a converted pressure cooker. I think it is important to note here that you need to be very careful whenever you are working with steam and pressure. Be sure to have proper safety precautions in place and our method may not work for other setups/barrels. And there is definitely room for improvement.

We used a converted stovetop pressure cooker with the primary weight-based pressure relief valve removed to have a hose attached to this opening. This hose was then put into a bung in the barrel, transferring the steam from the pressure cooker to the barrel. We still had multiple levels of pressure relief. First off, the secondary pin to release pressure on the cooker was in and therefore there was pressure relief on the cooker side. Secondly, we had multiple press-fit connections leading to the barrel to serve as release points in case we built up too much pressure. These were the connections from the tube into the bung as well as the bung in the barrel, which was not forced down as tight as one might do when aging in the barrel. We knew from experience with the racking cane that the bung could pop out under a low pressure when it is not strongly forced into the barrel.

Steaming the barrel.
We started the steaming of the barrel with our "Vinnie nail" out, allowing venting of the steam out of this opening. With this, while steam entered the barrel, the barrel was not warming up as much as we would have liked. So we replaced the nail after about 5-10 minutes and continued steaming in a closed system with the aforementioned engineered weak points (or if German-inclined, sollbruchstelle - one of my favorite German words). I didn't keep good track of steaming time, but it was clear the steaming was doing its job. First the heads of the barrel became warm to the touch. The exterior of the barrel was wet from rinsing before the steaming, and we could see this moisture evaporating away. Then the sides of the barrel also became warm to the touch. Eventually our engineered weak points did their job, venting the pressure, and we decided to end the steaming there. We felt a sufficient enough job had been done as it was probably at least 20-30 min of total steaming (with and without the nail in place) and all exterior surfaces of the barrel were quite warm.

With a bit more planning time we'll hopefully have a better setup next time. I think it wouldn't be too tricky to work in a pressure relief valve like. Basically the same design as the racking cane should work (and only a T fitting would be necessary, rather than the cross on the cane). Though again, from out experience, the bung on that cane pops out before the pressure relief valve is active anyway. But more pressure relief options are probably not a bad thing. Another option would have been to try longer with the sampling nail out. Perhaps with more time to build up heat this would have worked well.

Filling
We returned the morning after our brew day to fill the barrel. The pots that could be lifted easily were carried over to the barrel for filling. The others were transferred into intermediate smaller pots and then carried over. Filling the barrel went fairly smoothly, but it was clear fairly after working through the conical that we had undershot our volume. We had a bit more than expecting in our evaporative loss. And a calculation error meant that we were high in gravity but low in volume. This was an easy problem to solve and we diluted in the barrel with extra water (which had been heated to above pasteurization temps from the day before). In the end, based on a gravity points and volume calculation, we had an OG of around 1.055.

Other than this volume challenge, and some slow flow on one of the kettles due to clogging a hop filter, the filling of the barrel went pretty smoothly. We ended up leaving a small amount of head space in the barrel. It probably only amounted to about 10-15 L, but we figured this might help keep the avoid absurd blowoff while still keeping the barrel almost completely full. And we filled a carboy with the extra wort for fully topping up the barrel after primary.

Fresh greens and cleaning, an important part
of every brewday. photo: J Young.
Interestingly, there was a clear difference in the fermentation progression of the barrel and the carboy. This fits with data on the inoculation of lambic from Spitaels et al. (2014), which reported microbes present inside of cleaned barrels that weren't detected elsewhere in the brewery. It is certainly possible to clean a barrel more thoroughly than we did, but I think we did a pretty reasonable job with the physical removal and then given how warm the outside of the barrel was after steaming.

For me, this difference in fermentation from the two vessels helped to confirm previous anecdotal experience form myself and other as well as available published data that fermentation vessels can impact inoculation in spontaneous beer. I am not very convinced that a barrel can be made sterile / as clean as a carboy and I think this can be important. Anyway, after a few months (from reports from the other folks involved in this brew) the carboy was a bit unpleasantly bitter while the barrel did not have this bitterness. The carboy was transferred into the barrel after we felt that the risk for blowoff was gone. The barrel also developed a bit of a "sickness" after active primary fermentation while the carboy did not.

I'm excited to see how this beer develops over the coming year(s). Hopefully I'm back around to deal with it when we remove it. And hopefully I can be involved in the next ill-advised filling session. Our plan for now is to let the beer go in the barrel for a couple years, while monitoring it's progress here and there. We're certainly not in a rush to empty it and re-fill it.

Monday, August 21, 2017

A quick autobiographical update

I wanted to give a quick update on what I'll be up to in the coming months (to years) and how that will influence the trajectory of this blog. While there isn't really much beer content in here, this is a bit long for a FB post so I thought it should stand as an autobiographical blog post of sorts.

Picking sour cherries in Bern, summer 2017.
Starting in October I'll be moving to Bern, Switzerland to take a 2 year position as a post doctoral researcher. In may ways this will help me maintain the trajectory of the blog over the past few years (in itself, this has been caused by similar life circumstances). I've made at least one trans-Atlantic move every year since 2013, and these trips have become more frequent and for a shorter duration in recent years. So I'm hoping this time there is a bit more stability.

For the blog, I think while I expect to be brewing much less, I think the writing will mostly stay the course. While having a base in continental Europe means leaving brewing gear behind, it should help me maintain access to the sorts of historical sources and modern brewers that have featured in many of my posts over the last few years. So I expect I'll be more likely to write the sort of posts that have been up recently - a focus on historical sources and scientific articles, and possibly a return to posts about commercial producers, rather than my own brewing. I am hopeful that I can get a bit of brewing in though.

While Switzerland may not be known abroad for it's beer, I think Bern is a good spot to end up. I've already met a homebrewer there (Tom) who is making good beer. Some of it is available commercially with his brewery Full Measure Brewing. While vising Bern I was able to pick some sour cherries with him and learn a bit about the Swiss beer scene. The area is also home to Sam, the writer of the (no longer active) Eureka Brewing blog and the co-owner of Blackwell Brewery. So there should be some good beer options around Bern.

Speaking at Carnivale Brettanomyces 2017.
Being based in continental Europe will also hopefully allow me to integrate a bit better into the European brewing scene. So far most of my time around European brewing has been getting to know commercial brewers. I definitely plan to continue that, but I'd like to spend a bit more time with homebrewers there. There is some great stuff going on in European homebrewing/blending (and very small scale commercial brewing).

While these brewers are often operating with similar influences to what drives North American homebrewing, and while there are points for the two realms to interact such as Milk the Funk, I think the two sides could benefit from a bit more crossover. But major events (like HomebrewCon and Carnivale Brettanomyces) can already have a non-trivial cost when considering places to stay, etc. It doesn't get better when you add international flights to the bill. And the almost overlapping schedules of these two don't make it any better. But it would be great to see more crossover at these events. So I'm hoping that I'll be able to learn from and collaborate a bit more with European homebrewers while I'm in Switzerland. Feel free to get in touch if you're a homebrewer based in Europe and hopefully we'll be able to meet up at some point over the next couple years.

Monday, July 24, 2017

White Beers of Northern France

About a year ago I posted a brief bit of information about bières blanche from northern France on the blog's facebook page (here and here). Thanks to a friend in Brussels with a good library of historic texts, I was able to locate a bit more information about these beers. This post expands on those initial FB posts with the additional info that I've tracked down. But there is still a long way to go to understand these beers, and I'll continue to look for more sources.

Introduction
The Nord region of Northern France was an active brewing center around 1900. At this time, breweries in the region were still producing traditional beers of top fermentation. The influence of imported lagers was shifting brewing elsewhere in the country toward lager production. Unfortunately, while traditional beers could still be found in the Lille and Dunkirk areas, they were also in a period of decline here. With WWI coming and the state of brewing in the region already in a tricky spot, the region saw large changes for brewing in a rather short amount of time. I've written about biere of the region in these two posts here (mainly on mashing) and here (mainly on WWI).

Perhaps not a brewery making a blanche, but I wanted a photo generally related
to historic French brewing. From the breweriana collection of D. Thiriez.
So back to the beers of the Nord. Most of us have probably heard of one of these traditional beers - bière de garde (note that bière de garde in 1900 was different from the modern versions) - but other beers were made in the region as well. And I haven't seen much mention of these other beers. While looking for information about French bière de garde about a year ago, I found mention of a bière blanche. I hadn't heard of this beer before and it interested me, but there was very little info to go on in that brief mention. With this new source I'm starting to get a bit of a better picture about this beer and wanted to put up what I know at this point.

Of course, as with other posts on historic brewing, the same caveats apply - namely that this is a small snapshot of the beer (as the beer likely changed over time as well as among different producers) and this understanding is limited to the info given in a few sources.

Blanche de Cambrai
This discussion draws from two main sources - Petit Journal du Brasseur (1910) and Moreau and Levy (1905). The both refer to blanche in general and the latter specifies a beer called Blanche de Cambrai. In the modern world, this latter name applies to a distinct beer made from one brewery. But historically it was a style of beer brewed by many brewers in the region. The same thing - where a style turns into the product of only one brewery - can be seen elsewhere in Europe (e.g. Grisette and Hoegaarden). I'm not sure if the brewery making Blanche de Cambrai holds a trademark on the name, as is the case with the other two examples. When discussing Blanche de Cambrai for the rest of this post, I am referring to the historic style rather than the modern brand name.

Historic Blanche de Cambrai mostly matches the general description of blanche in PJB, but there is a notable difference in attenuation. On the whole, these white beers don't seem very common but they were produced at multiple breweries in the early 1900s. They are noted as having a short boil or possibly none at all (though in the latter case beer would be held at boiling temps, so maybe more of a simmer than no boil in the modern sense). For the time this is quite unusual as beers could easily have a multi-hour boil, possibly approaching 8-12 hours or more.

The blanche beers seem to be of moderate gravity (~1.035-1.040) and were lightly acidic. Some of the parameters of the beers are shown below, along with comparison to other blanche beers and acidic beers, both modern and from ~1900. These northern French white beers are described as having a good hop aroma. The attenuation was either moderate or high. It seems the beers were consumed around 3-4 weeks from brew day (or possibly a week or two older).

Parameters of northern French Blanche and historic and modern Belgian and German acidic beers.
Brewing
The grain used is described as being as pale as possible. Moreau and Levy note that an ordinary brown beer was brewed at the same time and from the same grist as this white beer (this brown beer is not completely straightforward, but that is a topic for a later post). Unlike bière de garde, which would use a form of turbid mashing, it seems that the white beer is produced by infusion mashing. About 25-30 kg of grain is used for 100 L. I interpret this to mean 100 L of each blanche and brown beer (it isn't explicitly clear, but given context and expected extract this seems necessary). There is no discussion of grain breakdown (and actually no mention of wheat by name in either source). The barley used in this region was mostly a winter 6 row. There is also general mention of brewers in the region using a bit of straw to help with the lautering, which agrees with other beers brewed with wheat at the time in Belgium such as lambic and grisette (as discussed here). Moreau and Levy note that some brewers use rice.

Initially a cool infusion is made and the mash is quickly drained. This is effectively a rinsing, and is done to remove some of the color of the grain. This rinse is held to the side and will be added the the brown beer. Then the mash is raised to a low saccharification temp, where a long rest is performed (~1 hour of stirring followed by 75 min of rest). After this the mash is drained and first runnings become the white beer. Note however that the white beer is not especially strong. The remaining runnings (and the cool rinse) going to the brown beer.

The white beer portion is boiled for up to about an hour (though Moreau and Levy note that some brewers only hold the wort near a boiling point, in agreement with PJB). Hops are only added in the cooling tuns or at the end of boiling (preferably in the cooling tun), but the hopping rate is fairly high at ~9-10 g/L (compare with grisette and saison/Belgian bières de garde here and with lambic here). Moreau and Levy note that some brewers spiced their beers with coriander, star anise or iris.

The beers are fermented with ale yeast (which, given the time means a mixed culture of bacteria and/or other yeasts such as Brettanomyces). Although the hopping was high, the hops were not boiled and some acidity is able to develop. The beer was bottled (with priming sugar) after a couple weeks and was carbonated a couple days later.

Final Thoughts
All this seems like an interesting beer - light acidity, low gravity (in the modern sense) and hop flavor but not so much bitterness. It sounds like it would be pretty refreshing. The brewing process described in Moreau and Levy seems pretty unique and I wonder if other brewers in the region followed a different process for their beers. And/or if similar process shows up for other beers elsewhere. Overall I think this is a cool, if uncommon, component of northern French beers from ~1900. And hopefully I can find some more info elsewhere about these beers.

Sources for the text:
Petit Journal du Brasseur, 1910
Traité Complet de la Fabrication des Bières (1905), Moreau & Levy.

Tuesday, July 11, 2017

Lambic attenuation and carbohydrate composition

Here are some data on the carbohydrate composition of lambic and how this composition is modified throughout lambic attenuation. The data come from the PhD thesis of H.M. Chandana Shantha Kumara (KU Leuven, Verachtert Group), which focuses on lambic attenuation and identifying the key players responsible for causing the high attenuation of lambic relative to most normal beer. There is some great work in the thesis, especially in showing the microbes and microbe combinations responsible for the attenuation and characterizing the enzymes driving this. Parts of this thesis have been published as scientific papers (here, on identifying super-attenuating microbes, as well as these two papers on characterizing and localizing glucosidases in brett and in Lactobacillus) but I have only seen this specific carbohydrate data in the thesis itself.

The thesis.
Many people likely heard something to the effect of "lambic uses a turbid mash, which produces longer chain carbohydrates that help to provide food for organisms like brett over the long fermentation". While I believe this to be true and it makes logical sense, there aren't a lot of studies (other than this one) that provide clear evidence to how that happens. And this is a fairly basic statement. I'm interested in more specifics about turbid mashing so I've been thinking about questions to look into and have been looking for info that might provide a bit more detail. For example, different lambic producers are using different turbid mash schedules. And there were many other schedules used historically (and not always to provide a food source for microbes over a long time period as is the case with lambic). I've written about a couple other schedules in these posts on French bière de garde and low-gravity Belgian beers. So how much do the variations in specific schedules change the final beer? And how much do the variations in turbid mashing change the fermentability of the wort to more normal brewing yeasts? And then what classes of 'unfermentable' material that is carried into the wort from turbid mashing is accessible to the yeasts and bacteria active at 1-2 years in fermenting lambic? This PhD thesis provides some info on that last point.

Sampling and the Data

Samples were collected at one brewery from barrels of different ages. My interpretation from the text is that all the samples were collected at one time point and therefore that they are from different brew days and brewing seasons. But this could be a misinterpretation as it isn’t completely clear from the text. If my interpretation is correct, then some of the variability over fermentation could be due to differences in the starting points. However, since the samples are all coming from the same brewery using (presumably) one consistent process, the batch-to-batch variability is likely to be smaller than many of the general trends.

This post shows a couple figures I produced with data presented in chapter 3 of the thesis on carbohydrate composition from lambic of different gravities. The carbohydrates are broken into groups depending on how many individual sugar units the carbohydrate is composed of. So this ranges from a simple 1 unit sugar like glucose, 2 unit sugars like maltose, up to carbohydrates made up of more than 100 glucose units. This size class breakdown will be the focus of the following discussion.

Composition of wort

To begin with, I want to say something about the wort before fermentation. The specifics of the turbid mash schedule aren't supplied in the thesis and the brewery is not named. One could infer the brewery based on the data and other info in the thesis but I don't think that is much of a priority given the small amount of information out there about turbid mashing.

The composition of carbohydrates as a percentage of the total (by mass) is shown in the figure at right. As with other mashing procedures, the composition is dominated by simpler carbohydrates (1-3 sugar units). And the two smallest groups account for ~80%. But I think it is interesting to note that with this turbid mashed wort, the next largest component is the longest sugar chain grouping. These results are by mass rather than by number of molecules, so it is fewer but larger molecules in this class compared to other classes. But still, in terms of the total number of sugar units present in lambic wort, the third largest fraction is the biggest molecules.

I should also note here that the OG of the wort isn’t specified, but I am assuming it is around 13° P as this is where all the standard lambic OG data I’ve seen falls (± ~1° P).

Carbohydrates during attenuation

The initial half of fermentation (by gravity, not time) is accomplished by fermentation of the smaller chain sugars (<3 and 3-6 units), with no appreciable decrease in the longer chain carbohydrates. This makes sense given the microbial start of lambic fermentation – enterobacteria (in breweries not acidifying wort) and select yeasts (e.g. Kloeckera/Hanseniaspora) that utilize only very simple sugars (frequently only glucose) followed by Saccharomyces. These organisms can’t access the longer chain molecules that remain generally unchanged in the first 50% of attenuation.

Carbohydrate composition of fermenting lambic with a full y-axis scale at left and a reduced scale at right.

By the time attenuation reaches ~75-80%, the >185 and the 30-61 unit size classes decrease, showing that the microbes responsible for the high attenuation of lambic have started to work on these. Interestingly, at this point, the 6-30 unit class concentration increases and the carbohydrate concentration of this class does not drop below its initial level for the remainder of fermentation. The persistence of this intermediate class is a pretty novel finding. Dr. Shantha Kumara interprets this as the larger size classes being first cleaved by endo-glucosidases (enzymes acting in the middle of the molecules) to smaller sized molecules including the 6-30 unit range. These smaller ranges are then processed by the cells (either extracellularly and then fermented or internalized directly). So the large carbohydrates are made available by first being broken down extracellularly, leading to a net 6-30 unit carbohydrate production in the lambic, followed by a consistently elevated (though decreasing) 6-30 unit class throughout fermentation.

If this all sounds too complicated, you can picture the different carbohydrate pools as buckets of water with holes in the bottom. Water is draining from the buckets through these holes (carbohydrates are broken down into smaller molecules and/or fermented). For the 6-30 unit size class, you are also adding water (the larger molecules are broken down into 6-30 unit-sized carbohydrates) such that the total level of water in this bucket is rising even though some is still draining out. Eventually you reach a point where you are adding the water more slowly because there is not much left to add (the large size classes have fewer molecules to be broken down to the 6-30 size class) such that the water level in the 6-30 unit bucket can fall again.

Percentage of different carbohydrate size classes in fermenting lambic.
As the lambic reaches final gravity (in this case testing stopped at 1° P, though note that many lambics don’t finish this low), the two largest remaining fractions are the 6-30 unit and the 3-6 unit carbohydrates. I found this quite surprising as I would have expected the more simple molecules to be processed more easily. So perhaps there is still a bit of fermentation going on at this point. Either way, the 6-30 unit class is maintained in appreciable concentration throughout the fermentation while larger molecules are more completely used up. The result, in final or near final gravity lambic, is that the residual carbohydrates are dominated by 3-30 unit carbohydrates while the shorter and longer chain molecules are more completely removed.

The same trend can be seen in the data when looking at the relative carbohydrate composition, where the percentage of the 6-30 unit class increases from ~1/2 attenuation onward and the percentage of the 3-6 unit group remains roughly constant or rises slightly. So at the final gravity point measured here (1° P) these two size classes are the most prominent. In contrast to this, there are basically no carbohydrates left in the 30-185 size classes. The >185 size class counts for a similar percentage in wort as in the final lambic, so there is still something left in this class at the end of these measurements. But the non-normalized data show that there was clear removal of this size fraction during fermentation.

 Thoughts for the future

This study did a great job of showing how lambic wort from one producer using one turbid mash schedule was attenuated over the course of fermentation. But I would be interested to know how this might differ with other producers. What if a different turbid mash schedules produced more long chain carbohydrates? Would this influence the FG? We know that a good number of lambics do not attenuate as far as 1° P, and this is driven by microbes and/or hot side process. The degree to which the microbes in this study were able to access the longest chain carbohydrates suggests that mashing to produce even more of this size class would not result in much of a change in the FG. And therefore that the differences in FGs among different lambics might be due in large part to the capabilities of the different microbes. This interpretation fits with other lambic attenuation data that I’ve seen (though expanding on that is a topic for another post). Additionally, if this were the case, it would highlight the inter-producer diversity of lambic microbes.

None of the above discussion of how different turbid mash procedures may influence beer addresses flavor production. Of course there is the flavor of the wort, which one might assume could vary by different mashing process given that turbid mashed wort tastes different from infusion mashed wort. But there might also be differences in microbial flavor development if the composition of more complex molecules was altered. So there are still plenty of questions to address here.

Finally, I’m interested in more info on turbid mashes compared to conventional mashing. There is unfortunately not quantitative data in this thesis comparing the carbohydrate composition of lambic wort to normal beer wort. But qualitatively, there is a figure showing that lambic has higher levels of carbohydrates with 4 and more sugar units than lager beer. This is especially the case for longer chain compounds that likely have tens to hundreds of sugar units. That is unsurprising, but it would be interesting to have a more quantitative measure to compare. I suspect info like this is out there somewhere and maybe I'll track some down and work it into an update of this.

Monday, June 12, 2017

100 year old Czech beer

This is a post about a recent paper by Olšovská and co-authors looking into the characteristics of ~100 year old bottles of Czech lagers. These beers had been discovered at the site of an old brewery during construction and based on the nature of the found beers, they had (presumably) been stored under fairly ideal conditions. The researchers took advantage of this fortuitous discovery to note the characteristics of the aged beers, as such an opportunity to test 100 year old beer does not come by very often, and to try to learn about what the beers may have been like originally. Here is a quick summary of some of the findings with a focus and further thoughts on one of the three samples which the researchers described as "resembling lambic". They make this comparison, which is what brought the paper to my attention, due to the properties of the finished beer and the presence of Brettanomyces. As with trying to understand such old beers with minimal data, there is a fair amount of conjecture involved in this discussion.

Acetic acid and lambic-like lagers?
A comparison of a ~100 year old Czech beer and various lambics.
While I found this paper rather interesting, I think the authors were mistaken to say the beer resembled lambic. Since it was brewed as a lager, we can be sure that it did not follow lambic-like brewing process in some pretty fundamental ways. Putting that aside and only looking at the parameters of the beer, it is also rather unlike lambic. A comparison between the 100 year old Czech sample and various lambics is shown at right. A necessary caveat here is that I am not comparing to 100 year old lambic. I have data from lambic from ~100 years ago (see the notes regarding these data in this blog post about Duivelsbier), a sample of 1970s atypical lambic (to try to approach the acetic acid and acetic:lactic acid levels in the Czech beer) and data from the oldest bottled lambic I could find - ~17 years old. These are all a far cry from ~100 years in the bottle, but, as reasoned below, I think they are sufficient to say that the comparison is not accurate.

The first part that jumped out at me was the very high acetic acid in the beer and comparatively low lactic acid. Assuming there is no typo here, this acetic acid level is at least 4 times higher than I have seen for normal lambic or gueuze. The lactic acid values of the lager are in line with some lambics, but not with data available for aged lambic. And it is surprising to me that the acetic levels are three times higher than the lactic levels in the Czech beer. Meanwhile, with lambic, I haven't seen a beer where that ratio of acetic:lactic is much over 1:1, and generally it is much lower (closer to 0.1). The values of ethyl acetate and the comparison of ethyl acetate to ethyl lactate shows the same trend.

An add for vinegar to add to beer or wort from PJB 1922.
So it seems that the aged Czech beer went though some sort of assertive acetic production, through either acetic acid bacteria or Brettanomyces in the presence of O2, that isn't found to a comparable degree in lambic. And therefore the beer neither resembles lambic brewing process nor the final characteristics of lambic.

While this doesn't reflect lambic, I think it is interesting to note the acetic presence in this one sample of the Czech beer. It is possible that this developed in the bottle, but that is a lot of acetic acid! Modern distilled vinegar has only about 5x more acetic acid than this beer, compared to about 50-100x more acetic in vinegar than in modern lambic and Flanders red beers. If the acetic developed in the bottle, that would likely require a dramatic failure of the seal sufficiently early on such that the brett and/or bacteria present were still viable. This should then also result in some major changes to the beer (like it evaporating away over 100 years) and therefore I don't think this is likely the source of the acetic. So I think it is reasonable to assume that at least a good chunk of this was present in the beer before bottling. And, therefore, that the brewers knew about it and bottled the beer anyway. The intentional bottling and (presumed) selling of acetic beer (that may or may not have much lactic acidity), occurred at this time in regions of Belgium as well and I think this is an interesting piece of beer history (though, again, I don't think it would have been common for the acetic levels to be quite so high).

An ad for vinegar for blending from Petit Journal du Brasseur, 1924.

Acidic lagers?
Moving on to a focus on lactic acid, all three ~100 year old Czech beers tested had lactic acid levels which are comparable to modern acidic beers (2500-3500 mg/L). This is a good deal above what you might get from malt and I found it to be a pretty cool part of this paper. It made me wonder about how much lactic acidity was in the beers when they were bottled compared to how much developed in the bottle over time. Spitaels et al., 2015 (discussed in this blog post) showed aged bottles of Cantillon gueuze have considerably more acidity than fresh bottles.

As discussed in that post, it is hard to tell how much of this difference may be due to aging compared to changes in brewing/aging/blending process which might yield less acidic beer. But, if even half of the difference is due to development in the bottle, the level of lactic acid noted in the Czech beers could develop within a 5-10 year time frame from bottling. So, with this assumption, the levels of lactic acid in the Czech beer are consistent with a perceptibly clean beer being bottled. Therefore, perhaps the beers seemed lactic-free when they were consumed and it only showed up in these aged examples. But I don't think it can totally be ruled out that there was some present at the time of bottling and that fresh examples of the beer may have shown this.

Brettanomyces
The presence of brett, by detection of Brettanomyces bruxellensis DNA, was noted in the sample which was compared to lambic. I found this interesting given the transition to 'clean' lagers around 1900, while ales were still mixed culture beers (even if brewers wanted them to be clean). I don't think much about historic lagers with brett but I think it would not be unreasonable that it was likely present in some and, depending on temperature, could have made a flavor impact. Brett can grow at 15 C (see the MTF wiki here) and likely cooler. I know that lambic cellars can spend a good part of the year cooler than this and lambic seems to still show biological developments over this time.

So I think it would be interesting to learn about historic lagers with a brett presence. There are certainly examples of brett in lagered beer added for a secondary fermentation. Some of the early tests with Brettanomyces resulted in the development of 'English' flavor in lager beer. These were used to help identify brett as the organism responsible for this flavor. And there are plenty of modern beers which start their lives as lagers and after further purposeful pitching become mixed culture beers.

I'm more interested in the natural development of brett characteristics in lager beer as it is aging, such that the final beer would be lager-like except with brett rather than initially a lagered and then warmed and pitched with brett. I know that Clausen, in his patent for brett, noted that it would not impact the flavor of lager even after multiple months at lager temps, so it could be that only warmer lagers or packaged lagers that were stored warmer for some time before consumption would start to show this character. Given the range of lager production I think it would not be surprising to find that some regions, possibly where lagering was conducted a bit warmer in pre-refrigeration days, may have had lagers showing brett character. I don't think this would have been common by any means. But perhaps a rare regional phenomenon much like Orval surviving as a brett beer (albeit an ale) to the modern day.

Closing
There's definitely other interesting stuff in the Olšovská et al. (2017) paper but I think this is enough for one post. To sum up, most of my lingering thoughts about this are fairly unanswerable (mostly to the effect of: what did the beer taste like when it was young?) but I think some of these questions would be interesting to approach with modern brewing. Brett was able to get into one of these three bottles. At the latest, this would have come at bottling/in the bottle. From the acetic discussion above, I think there was at least some acetic-producing organism before bottling (but, of course, that assumption couple be completely wrong and this could have developed only in the bottle). Any earlier, and brett would have been present in the trub and possibly in the repitched yeast at the brewery. If it is present in the repitched yeast at the brewery to an appreciable degree, than maybe it is active in the fermenting and aging beer, and maybe it is making an impact.

So as homebrewers this can be tested. How low can you go and still have brett impact the beer to a noticeable degree on a timescale of months. I suspect it would at 50 F / 10 C. What if you brewed a lager beer with brett and kept it at 45 F / 7.2 C for the lagering phase? Can you go even lower? Of course this would be strain dependent. Given the invention of ale/lager hybrids (e.g. steam beer), it is clear that lager-like processes were not restricted to beers fermented and/or aged especially cold. Perhaps in addition to these, beers thought of as more classical lagers were not aged as cool as elsewhere/as they are in the modern era of refrigeration. And I think an Orval-analog of lagers would be an interesting beer. And then there is the question about the lactic acid in the beers...

So plenty of questions for the future. But overall I think it is possible that lagers, at least during a certain time frame and in certain areas, were not always as 'clean' as we consider them to be.

Edit 12-June-2017: I've been thinking this over throughout the day and I am not thinking there may be a better chance that the acetic could be all or primarily generated after bottling. I'm still pretty unsure about it and the above discussion (that I think it would take a significant failure in the cork to general that much acetic) holds. And, if that happened, then I would expect this to be reflected in fill heights, which would then be apparent in the un-opened beer. The authors don't note fill heights in their paper so we can't really tell here.

My thinking that is swinging me more toward a bottle issue is that this is a lot of acetic acid. To a degree it may be more like vinegar than typical acidic beer. And I am having a bit of trouble thinking of why such a beer would be bottled (at least if it were intended to be a clean lager, which is the premise that the authors seem to be operating under). Anyway, I am content to settle with we'll never know. And I am still pretty split on where I think the acetic was generated. But the root question this prompted still holds - were there beers of lager fermentation which displayed brett characteristics with any sort of regularity? And, if so, where were these beers found and how long did they last?