Tuesday, January 22, 2019

Spontaneous fermentation and biogenic amines

Biogenic amines (BAs) are a class of biologically-produced compounds that are found in plant and animal products such as cheeses, cured meats, and other fermented foods. The names of some specific BAs may be familiar, for example histamine, and others may illustrate the sorts of characteristics some BAs have (strong bad smells), for example putrescine and cadaverine. As the names of these latter two suggest, some BAs are associated with rotting material. In higher levels BAs can have health impacts, but I won't be discussing any of that. If you want more health-related information on this, check out this great complimentary post by Bryan at Sui Generis Brewing.

In beer, BAs can originate from raw ingredients and can also be microbially produced during fermentation. Especially in fermentations that are not pure cultures of S. cerevisiae, much of the BA content of beer can be formed during fermentation. This post will focus BAs in spontaneous beer by looking at data of BAs in lambic, with an emphasis on microbial BA production points, how this may impact the flavor and aroma of spontaneous beer, and how production can be minimized without inoculation (i.e. while maintaining a spontaneously-fermented beer). I won't go into much lambic background in this post, so if you're unfamiliar with the process and/or fermentation progression of lambic and other spontaneously fermented beers, then I recommend starting with this page on the Milk the Funk wiki and these pages (here and here) on lambic.info. You can also find all of my previous posts on lambic (history, hopping, IBUs, carbohydrates, commercial brewery/blendery visits, etc.) here.

A coolship being filled
As with my other posts on beer science, this might be a bit dense for those not so interested in science. Here is a simplified summary if the details are a bit too much and/or you're not interested in that part:

Biogenic amines seem to be produced in two different phases in spontaneously fermented beer - one from enterobacteria in the initial weeks and one from lactic acid bacteria after about 6 months. BA production in the first stage may be controlled/limited by pre-acidifying wort. Differences in BA production in the second stage may be due to differences in specific strains of lactic acid bacteria, as not all can produce BAs. There aren't enough data to be sure, but BAs produced in the first stage could impact the flavor/aroma of spontaneous beer.

Biogenic amines in lambic

The data sources
I will be primarily discussing two studies on BAs over the course of lambic fermentation - Gasarasi et al., 2003 and De Roos et al., 2018. The former followed the fermentation of un-acidified wort for 400 days, and also followed fermentation of wort which they pre-acidified with 5% of a very acidic beer. This beer was prepared from the previous brewing season by pitching wort with pure strains of lactic acid bacteria. It does not seem that this ~6 month old acidic beer was sterilized before using it in the next season at a level of 5% (contributing about 1g/L lactic acid). This second beer was followed for a total of 60 days. If this acid beer wasn't sterilized, that is unfortunate because it means the beer is no longer spontaneous. The authors also briefly mention tests with simple pre-acidifying with lactic acid, which they say resulted in a reduction of BAs, but unfortunately they do not show the data or discuss it further. The second study (De Roos et al., 2018) followed two different 660 L casks of lambic from the same brew from the time the casks were filled until they were two years old. The wort for these casks was pre-acidified to pH = 4.3. Finally I am including data from two different studies on finished lambic & geuze - Izquierdo-Pulido et al., 1996 and Loret et al., 2005.

Stage 1 - Initial days and weeks
Looking specifically at beers of spontaneous fermentation, there appear to be two periods where BAs are produced. The first point occurs early in the fermentation where enterobacteria are active, beginning in the initial day(s) after cooling and lasting for the first week(s) (e.g. Van Oevelen et al., 1977; Spitaels et al., 2014; De Roos et al., 2018). At this point in the fermentation, no significant attenuation has occurred so simple sugars are available and alcohol is absent. The pH is also higher at this early stage. During this stage the primary BAs produced are putrescine and cadaverine.

Variability is seen among available data for putrescine and cadaverine production at the start of fermentation. See, for example the differences in cadaverine and putrescine between the filled green circles (Gasarasi et al., 2003 data of lambic wort which was not pre-acidified) and the open green circles (Gasarasi et al., 2003, lambic wort which was pre-acidified). Additionally, the Gasarasi et al., 2003 un-acidified wort shows much higher putrescine than the De Roos et al. (2018) data. It should be noted that this comparison is between different batches of lambic from different years and from different producers, so there could be additional sources of variability. The difference for putrescine may be important, even if cadaverine levels are similar, as putrescine is more likely to have an impact on the taste and/or aroma of lambic at the observed concentration levels. This is discussed in more detail in the taste section below.

BAs in fermenting & packaged lambic. Data in black squares are from final products. An age was chosen
(~800 days) to include them in the figure and does not reflect their actual age (which is likely much older).
The ability of pre-acidification to limit BA levels in the initial production phase is because pre-acidification can limit and/or shorten the period in which enterobacteria are active in the wort. Both the Gasarasi et al. (2003) and De Roos et al. (2018) studies highlight the potential of wort pre-acidification to limit BA production in lambic. Gasarasi et al. (2003) note that pH > 5 and cooling to T < 15° C may result in elevated BA levels, and they say that adding 2000 mg/L lactic acid to wort reduces BAs but does not completely prevent BA production. A study on industrial lambic production where the wort was acidified to pH = 4 with lactic acid before fermentation also demonstrated that pre-acidification can eliminate the enterobacteria phase of fermentation (Spitaels et al., 2015).

A stainless steel coolship
Takeaways for brewers from the first phase
For brewers wishing to pre-acidify their spontaneous beers, these studies provide some possible starting points. Note that I haven't tried any of these myself, I'm just summarizing the advice of the papers. The specific levels mentioned here (2 g/L lactic acid in one study, pH = 4.3 in another, which took a bit more than 1 g/L lactic acid; the latter here being what one lambic producer does) may be a good starting point. Using a lower pH (pH = 4.0, as used by an industrial lambic producer) may further reduce BA production by preventing the enterobacteria step. 2 g/L lactic acid sounds like quite a bit to me, considering Van Oevelen et al. (1976) report ranges of about 2-3.5 g/L lactic acid in finished bottle fermented geuze. As a comparison, the lambic studied in De Roos et al. (2018) finished with 4-5 g/L lactic acid, and the bottled gueuze samples from Spitaels & et al., 2015 finished with about 4 g/L lactic acid or more. Depending on where the beer finishes, acidifying with 2 g/L could mean half or more of the lactic acid in the final beer is from the pre-acidification.

Finally, blending in old acidic beer around 5% (for very acidic beer) before fermentation could be a good starting point. Depending on how you feel about spontaneous fermentation, you may want to do a quick sterilization of this to prevent inoculation with microbes from the old beer. Or you may view this as beneficial for your beers, by encouraging fermentation with proven microbes, even if it may make the beer not spontaneous/less spontaneous. Finally, Gasarasi et al. (2003) note that pH > 5 and temperature < 15° C seem to favor BA production. Something else to think about when pre-acidifying is that not all metals remain inert as the pH drops (see here and here). I haven't seen data to assess what specific pH values are too low for less inert metals, but it is something you may want to look into further if you are considering this and are not using stainless to cool the wort. Or just pre-acidify after the coolship.

Another stainless steel coolship
Stage 2 - After main attenuation
A second phase of BA production can be seen in lambic. This is most evident in the tyramine and histamine data, where concentrations increase only around 100 days into fermentation. In the course of lambic fermentation, this corresponds to the acidification of the lambic by lactic acid bacteria after the main attenuation has been accomplished by Saccharomyces (e.g. Van Oevelen et al., 1977; Spitaels et al., 2014; De Roos et al., 2018). Lactic acid bacteria are known to have strain specific variability in the ability to produce BAs. Therefore, differences between producers at this stage may result from different strains of bacteria in different lambics. De Roos et al. (2018) note that there is still some uncertainty regarding this phase of BA production, as the timing of BA production in their data lagged behind the peak in Pediococcus cell concentrations during lambic acidification. This second phase does not seem to have much influence on cadaverine and putrescine levels, though the De Roos et al. (2018) data do show a slight increase in putrescine here.

Comparing with finished products
Comparing the production data and finished lambic data shows some distinct trends (see the table below). First, BAs in lambic appear to generally be higher than in other beers. Data over the course of fermentation suggest that any putrescine and cadaverine produced during the initial stages of fermentation are not appreciably removed as fermentation progresses. This means that once they are formed, they survive at more or less the same levels to the finished beer. A comparison of the histamine and tyramine data from De Roos et al. (2018) with compilation of finished products shows a similar concentration range, suggesting that the same may be true for these BAs as final blends are made and beers are packaged.

The data from Loret et al. (2005) are an average of 42 products from a total of 10 producers. These data demonstrate strong variability between producers in histamine and tyramine (also shown in their Figure 3, see also the range in values from Izquierdo-Pulido et al., 1996 below). This may be controlled by variability in specific strains of lactic acid bacteria. Comparing putrescine and cadaverine data from Izquierdo-Pulido et al. (1996), Loret et al. (2005) and the two production studies, there is also a large amount of variability here. Some of this may be explained by differences in ambient brewery resident microbes and other variability. However, the data from De Roos et al. (2018), Gasarasi et al., (2003), studies of biogenic amines in other alcohols, and data on pre-acidification of lambic and enterobacteria, it is likely that much of this can be explained by whether brewers pre-acidify the wort or not. These biogenic amines appear to be formed early in the fermentation and pre-acidifying could significantly limit their production. Finer details within the Izquierdo-Pulido et al. (1996) cadaverine and putrescine data imply an interesting feature. These data show a mean that is toward the lower end of the total observed range (cadaverine: mean = 10, range = 0.4-39.9; putrescine: mean = 6.4, range = 2.8-15.2). In order for this to happen, the data must be composed of more low values with only one or a few large values. This could reflect a few producers which do not pre-acidify and have larger values of these BAs while others do pre-acidify.

Data of BAs in lambic beer and other beers.
Can BAs impact taste in beer?
The table above shows BA levels in lambic and other beers as well as taste thresholds for some of these compounds in water. This does not directly give information on their impact in beer because water lacks the other strong tastes and smells found in beer, making the threshold for detection in beer likely higher than in water. These thresholds also do not take into account any additive and/or synergistic effects that BAs would have when found with other pungent BAs and/or other compounds in beer, potentially resulting in lower detection thresholds. But these values give a starting point for an initial assessment of the potential for BAs to be flavor-active at concentrations relevant to spontaneous beer.

I could not find data on tyramine thresholds so I won't discuss that here. The histamine data are a physiological response but not a taste or aroma. And this threshold value did not hold in triangle tests. So I think the data I've seen so far suggest that histamine does not have a strong impact on flavor/aroma at the levels found in lambic. Moving to cadaverine, it seems that the levels found in lambic are much lower than those needed to detect it. However, putrescine can be found around or above the detection threshold in water. If any BAs are going to be flavor-active, it seems that putrescine is the most likely one. And with levels in lambic potentially >2x the detection limit in water, I think it is quite possible that putrescine can make a contribution to the flavor and aroma of lambic.

While much of the data included in this post have been available for 10+ years, this is a topic that I haven't heard many people talking about. Especially not before the last few weeks. I want to thank a certainly legendary producer for bringing this to my attention a year or two ago, and for helping me to connect this scientific explanation with something I had perceived and was having trouble naming. This post was also prompted and informed by discussions with some great Milk the Funkers/brewers/writers: Dan of well-deserved Milk the Funk Wiki fame, Bryan of Sui Generis Brewing and Matt of A PhD in Beer and Patent Brewing Company.

22-Jan-19 Updates: the takeaways from the first phase section was updated about 3 hours after initially publishing the post to include context for pre-acidifying levels relative to final lactic acid in geuze and to include how much lactic acid was needed to pre-acidify to 4.3. The references were updated to incorporate new references as needed and to include links to papers at this time.

-De Roos et al., 2018. Wort substrate consumption and metabolite production during lambic beer fermentation and maturation explain the successive growth of specific bacterial and yeast species. Front. in Microbiol. 9:2763. (doi: 10.3389/fmicb.2018.02763).
-Izquierdo-Pulido et al., 1996. Biogenic amines in European beers. J. Agric. Food Chem. 44(10) 3159.3163. (doi: 10.1021/jf960155j).
-Gasarasi et al., 2003. Occurence of biogenic amines in beer: causes and proposals of remedies. Monatsschrift für Brauwissenschaft. 56(3) 58-63.
-Loret et al., 2005. Levels of biogenic amines as a measure of the quality of the beer fermentation process:Data from Belgian samples. Food Chem. 89(4) 519-525. (doi: 10.1016/j.foodchem.2004.03.010).
-Rohn et al., 2005. Can histamine be tasted in wine? Inflam. Res. 54(S1) S66-67. (doi: 10.1007/s00011-004-0439-x).
-Romero et al., 2003. The influence of the brewing process on the formation of biogenic amines in beer. Anal. Bioanal. Chem. 376(2). 162-167. (doi: 10.1007/s00216-003-1885-2).
-Spitaels et al., 2014. The microbial diversity of traditional spontaneously fermented lambic beer. PLoSONE 9(4) e95384 (doi: 10.1371/journal.pone.0095384).
-Spitaels et al., 2015.  The microbial diversity of an industrially produced lambic beer shares members of a traditionally produced one and reveals a core microbiota for lambic beer fermentation. Food Microbiol. 9 23-32. (doi: 10.1016/j.fm.2015.01.008).
-Spitaels & Van Kerrebroeck et al., 2015. Microbiota and metabolites of aged bottled gueuze beers converge to the same composition. Food Microbiol. 47 1-11 (doi: 10.1016/j.fm.2014.10.004).
-Van Oevelen et al., 1976. Synthesis of aroma components during the spontaneous fermentation of lambic and gueuze. J. Inst. Brew. 82 322-326. (doi: 10.1002/j.2050-0416.1975.tb06953.x).
- Van Oevelen et al., 1977. Microbiological aspects of spontaneous wort fermentation in the production of lambic and gueuze. J. Inst. Brew. 83(6) 356-360. (doi: 10.1002/j.2050-0416.1977.tb03825.x).
-Wang et al., 1975. Apparent odor thresholds of polyamines in water and 2% soybean flour dispersions. J. Food. Sci. 40 274-276. (doi: 10.1111/j.1365-2621.1975.tb02181.x).

Monday, November 12, 2018

Saison from 1911 - finishing hops and coupage

A few of my latest posts were on the topic of industrial saison from the beginning of the 1900s (see this recipe with an infusion mash and this recipe with a turbid mash), and I'm returning to that topic here with a recipe from 1911. This recipe shares some similarities with the 1905 recipes, but what I find interesting about this recipe & why I am writing it up in addition to the other recipes is that this recipe seems geared toward a younger, less aged saison. I'll get into this in more detail in the post, but to begin with the recipe includes more of a focus on late addition hops and it mentions an optional cutting of the beer with lambic. Cutting (coupage in French) is something I want to return to in detail in a post to come. But for now check out these great posts from Amos at Browne & Bitter with coupage backgorund and some modern examples using this technique.

The begining of the article - a Q&A for brewing a saison year-round.
I'll present the recipe as it appears in the text, followed by an adaptation of the recipe to fill in some holes and alter it for more modern conditions. After all this I'll compare the recipe to other contemporaneous saison recipes I've written up and close with some thoughts on this recipe as fitting between other circa 1900 saisons and modern saisons.

The Recipe
-50/50 mix of French malt and Dikili malt. The recipe notes the French malt could be substituted for Escourgeon, depending on the season of brewing (the brewer specifies that this beer will be a year-round bottled product). In the latter case, the mash would start a bit cooler. Escourgeon is a winter 6 row barley that was common in Belgium at the time, and I’ve discussed this grain in the 1905 saison posts as well as posts about Bière de Garde.
-Optional 10-15% invert sugar - for prolonged storage the recipe says not to use it, but for storage of up to 3 months it is ok to use sugar
-3 kg hops per 100 kg grist (grain and sugar)

Mash in with water at 70-72° C (158-161.6° F) at 2 L/kg (~1 qt/lb) to reach a rest of 61° C (~142° F). Rest for 15 min and then underlet with 95° C (203° F) water to reach 70° C (158° F). A time isn't given for this latter step.

Boil for 3 hours
-1 hour without hops
-1 hour with 1.5 kg Poperinge hops of the latest harvest per 100 kg grist
-30 min left in boil: 3/4 kg East Kent hops per 100 kg grist
End of boil: 3/4 kg Bavarian or Bohemian hops per 100 kg grist (see previous discussions of hop hierarchies as linked in this post)

No information is given regarding fermentation (e.g. pitching rates, temperature). The beer is then clarified and clear beer is racked into barrels with 200 g East Kent hops per HL of beer (0.44 lb hops per 26.4 gal beer). The journal notes a minimum resting time of 2-3 weeks here.

The source mentions optional coupage with lambic (but no percentages are given)
An advertisement for lambic for blending from Petit Journal du Brasseur 1922.
Modern Adaptation
This is geared toward homebrew batch sizes, but this is easily adaptable to pro sizes with the original text and whatever modifications you wish. I'll give my reasoning for assumptions, modifications and/or additions to the original recipe.

Batch size: 19 L (5 gal) of wort, pre-fermentation
Target OG: 1.048 (I think ~1.045-1.050 would be good. No OG is given in this recipe, but this is reasonable for saison of the time, with bias toward quicker turnaround beers).
Approx ABV: 5.5%
Total Efficiency: 75%
Approximate IBU: 33.5 (theoretical, Tinseth) - I think the apparent bitterness would be higher than this given that this is derived from higher doses of low alpha hops, and that the dry hop is not adding any bitterness according to the calculator I used.

I haven’t brewed this, so this is simply a draft recipe as a starting point for you to work with based on other beers I’ve made and some changes I would make to this recipe to modernize it. If you do brew something like this, I’d love to hear your feedback on the recipe you use.

Grist and Mashing
Personally, I would lean toward the 100% malt option. As with the other saison recipes, I think a malt such as a continental European pale malt would be a good one to try. For 19 L at 75% total efficiency, you would need 4 kg (8.8 lb) of malt. You could optionally replace 400 g of this with about 240 g of sugar (or even a larger percentage of the malt with a proportionally larger amount of sugar), but I think the all malt recipe might give a more interesting beer.

This mashing schedule is pretty straightforward and I think it can be left generally as is. The 70° C (158° F) step could probably be lowered a bit (a lot of Belgian mash tuns from around this time weren’t good at holding their heat, so the mash could easily lower a few degrees C over an hour rest). And the 61° C (~142° F) step could extended as you wish. Especially for smaller batch sizes, the effective rest time at 61° C will be much shorter since the time to get the mash at this temperature is much shorter. So maybe 25 minutes at 61° C followed by 45 minutes at 68-70° C (154.4-158° F). There is no mashout specified in this recipe, but you can add one if you wish. That would be reasonable with Belgian brewing at the time.

Boil & Hops
Based on the high SA:volume ratios of homebrew setups, I think this boil could probably be shortened to 90 minutes or 60 minutes for homebrew scaled beers while  still keeping the spirit of the recipe and much of the characteristics of the beer contributed by the boil. Keeping the boil 2-3 hours on commercial systems may be better for following the recipe closer, but the boil seems to be less important in this beer than other recipes for Saison from the time.

I wrote a good deal about the considerations I took when trying to adjust hopping rates in old recipes (especially here). Landrace Belgian varieties of hops are nearly gone and tricky to source, but landrace hops from the other regions mentioned are still readily available so the hopping rates here may not need to be adjusted down as far. Still, it may be good to lower the bittering hops and/or choose low aa varieties (e.g. Strisselspalt), and possibly to lower the other hops slightly. Here is an amended hopping schedule for the boil, with the above-mentioned hop modernization adjustments and with some assumptions about batch size to convert to hops per volume units. I did not scale the hops down as much as I had in previous recipes, in part because of the varieties specified here. I used an assumption of 110 g (3.9 oz) total boil hops (the ratio of 3 kg hops per 100 kg grist in the original recipe would give 120 g hops in this scaled recipe). If your hops are stronger than the numbers below you could reduce the amounts (especially with hops earlier in the process) or stick to these numbers and see how it goes.

-2.9 g/L (0.39 oz/gal) Strisselspalt boiled for 1 hour (for the recipe calculations I used 2% aa, giving an IBU contribution of ~15)
-1.44 g/L (0.19 oz/gal) East Kent Goldings boiled for 30 minutes (I used 5% aa, giving about 14.5 IBUs)
-1.44 g/L (0.19 oz/gal) Saaz at flameout (for the calculations I treated this as a 15 minute whirlpool addition and assumed 4% aa, giving ~4 IBUs)

After primary, the beer would be dry hopped at about 2 g/L (0.27 oz/gal) with East Kent Goldings. This dry hop would last the duration of the aging (so about 2 months). Depending on how long you intend to age, you might want to transfer to a new vessel. I think on homebrew scales, for 2 month aging after primary and with a mixed culture, it would be fine to not transfer it.

Fermentation & Aging
I think anything from roughly 2-6 months grain to glass could fit, but personally I think I’d lean on the shorter end of this range for this beer. Roughly 3 months seems reasonable to me as a starting point. Given this time frame, if you have a mixed culture that gives fairly rapid attenuation and is good flavor-wise by 2-3 months then that would be good here. But otherwise it might be advantageous to use a more constrained mix of microbes and/or a pure culture. Other aspects of this recipe seem to point toward this being less acidic/vinous than other saisons of the time.

An advertisement from a brewer selling lambic for blending
from Petit Journal du Brasseur, 1924.
For the coupage component, this 1911 recipe does not specify how much lambic to use to cut the saison. The journal notes that the brewer would know best whether or not coupage would be a good idea as the brewer knows the taste preferences of their customers. Presuming you wanted to cut this beer with an aged, complex, acidic beer, the Petit journal du Brasseur provides some ideas in other articles from the late 1800 and early 1900s. An article from 1914 suggests to start with 5-6% lambic and work up from there, considering the taste preferences of the customers. An article from 1902 recommends using between 1% and 10% lambic pre-fermentation. And finally an article from 1898 recommends using 2-3% lambic pre-fermentation for an artificial aging effect.

The dry hopping recommended here would give a long contact time. I’ve seen suggestions along this line in other recipes and it isn’t something I had looked into much to get an idea how widespread it is and how it is generally accepted. Personally I would have said to lean away from such a long dry hop time but I wanted to get some input from others so I asked the Milk the Funk group. There were plenty of people there who had done long dry hops as in this recipe and were happy with the results (including some experienced home brewers that I trust as well  as some professionals making good beer). So I think a long dry hop as in this recipe could work out fine from a flavor point of view.

More importantly, the discussion highlighted to me something that I had underappreciated - the antimicrobial influence of the dry hop. I think including dry hops may be as much (or more) for preserving the beer from bacteria as for the direct flavor impact. This microbial control, as I'll get to below, makes me think this beer was intended for earlier consumption than some other saisons of this time period. Thanks to those who shared their experience in the MTF thread, and especially to Dan, Topher and Tommie for their thoughts/experience on the impact of hops here for continued antimicrobial protection.

Comparison with 1905 recipes
The hopping rate for the boil presented in this 1911 recipe is the same as the hopping rates presented in the 1905 recipes (~3 kg/100 kg grist in the boil). While these all come from the same overall source (Le Petit Journal du Brasseur), their consistency in these three responses from 1905-1911 for brewers using fundamentally different brewing techniques builds some confidence that this info can be trusted/is representative of at least what some brewers were doing. Though the timings of the additions and the hop origins are quite variable, even though the total amount is the same. In brief, here is what the recipes suggest:

1905 Turbid (total boil time of 8 hours):
  • 1 kg Alsace hops / 100 kg grain boiled for 8 hours
  • 2 kg Alsace hops / 100 kg grain boiled for 30 minutes
1905 Infusion (total boil time of 5 hours):
  • 0.62 kg Poperinge (Belgian) hops / 100 kg grist as first wort hops
  • 1.24 kg Poperinge (Belgian) hops / 100 kg grist boiled for 4 hours
  • 1.24 kg Poperinge (Belgian) hops / 100 kg grist boiled for 1 hour
1911 Infusion (total boil time of 3 hours):
  • 1.5 kg Poperinge (Belgian) hops / 100 kg grist boiled for 2 hours
  • 0.75 kg East Kent hops / 100 kg grist boiled for 30 minutes
  • 0.75 kg Bohemian or Bavarian hops / 100 kg grist at flameout
  • 0.2 kg East Kent hops / HL beer for dry hopping
The greater focus on high quality hops (German, Czech and English) and the greater focus on later hops in the 1911 recipe would both result in more hop character, which would obviously result in considerably different beers.

Grist and Mashing
All recipes are 100% malted barley (though the 1911 recipe optionally includes some sugar). Much like the hopping information, the uniformity here supports industrial saison around 1900 was a 100% barley beer, or at least that this was regularly the case. As discussed above, the grist suggestions also make sense for a beer that may see less aging. Both of the 1905 recipes recommend 100% Escourgeon. This 1911 recipe suggests either 50% French malt (the barley isn’t specified, but I would guess a spring 6-row based on Belgian barley growing at the time and the absence of the winter 6-row specification) or 50% Escourgeon. The remainder appears to be a Turkish malt. Additionally, if the 1911 beer was meant to be aged for less than 3 months, the recipe would optionally include 10-15% sugar. From everything I’ve seen, Escourgeon was the recommended grain for beers meant for aging at this time.

The section of the article giving dry hop amount, minimum
aging time, and the option of coupage with lambic.
The mash outlined here is much more simple than most Belgian mashes I’ve seen for the time, especially for beers for aging. Even comparing to many modern Belgian brewers this saison mash is quite simple.

Aging and Saison
The specific recipe presented in this 1911 article seems to be geared toward a saison that wouldn’t see as much aging as others of the time. I say this in part due to the hopping (more late hops, the dry hopping) and the malt, as discussed above. Additionally, the boil was shorter here and long boils were thought to benefit beers for longer aging. This 1911 recipe even puts additional emphasis on only boiling 3 hours, suggesting it was shorter than typical or what other brewers might expect. And the recipe mentions optional coupage with lambic. If this beer were going to be aged longer and allowed to acidify, then cutting it with a beer which had developed aged, vinous and acidic character would not be necessary or especially advantageous. But it seems here that the journal is providing this option as a way to add some aged character to the beer. Finally this 1911 response gives two slightly different recipes (with and without sugar) depending on if the beer will be aged for more than 3 months or not.

In comparison, the brewer for one of the 1905 questions notes a 5-6 month aging period and the other wants to brew somewhere around March (estimating the timing the question was submitted based on the time of the published response) for a beer to be served in August. So, from what I’ve seen in terms of hopping, process and specific aging times suggested, this 1911 recipe sits on the younger end of circa-1900 industrial saison and would likely produce a beer with comparatively more hop flavor. As such, when I’m looking at old recipes, this is what I keep in mind as a “hoppier” (more hop flavor, not necessarily more bitterness) saison from ~1900 rather a more vinous, longer-aged saison. Perhaps this difference  puts this recipe somewhere between a traditional historic acidic & vinous saison which had been aged 6+ months and the modern, more microbially pure, young and hoppy saisons.

Monday, October 22, 2018

A Recipe for Kriek from 1907

It’s been quiet on the blog for a while, but now I’m getting some time to write again. I wanted to start off with some more historic beer research – this time with info about kriek from Petit Journal du Brasseur in 1907. This volume includes two short sections on kriek production: one is an article from Robert Jordens and one is an answer to a brewer’s question.

Schaerbeek Cherries near Beersel, Belgium.
To start with, I think I should give a bit of general background. I'll be using kriek here to refer to lambic with sour cherries, rather than the cherries in general or any other base beer with sour cherries; however, the Dutch word "kriek" simply means sour cherry. The articles by Jordens notes that kriekenbier, beer with sour cherries, is made elsewhere but that kriekenlambic (much like lambic) is native to Brussels and the surrounding region. This article also refers to kriek lambic as “Belgian Burgundy”.

Oude Kriek and Kriekenlambic do have some legal protection (see also: here), which sets out ranges of fruit, some process/fermentation requirements, and some parameters of the wort. In addition, the "Oude" designation requires secondary refermentation in the package, conditioning on lees, and some characteristics (e.g. minimum acidity) of the final beer. Both designations appear to allow the use of cherry juices or concentrates and, interestingly, set a maximum cherry percentage which at least some commercial producers using the designations exceed. I found these surprising, and perhaps there is some updated legislation surrounding these.

A barrel at Cantillon with a painted square
denoting it has a square bung.
Schaerbeekse cherries are recommended. The article notes that some use Cerise du Nord (perhaps these are what you can now find called griotte du nord or Chatel Morel), sometimes mixed with Schaerbeek cherries, but that Cerise du Nord were not usually used alone as they are less fine and more acidic. The cherries are used whole (with pits) and fresh. Specific ratios of cherries are discussed below. The texts also recommend adding a sugar syrup (1/4-1/3 L per HL of beer) and a small amount of Ceylon cinnamon (10g / HL) with the cherries. The inclusion of cinnamon here is quite interesting. Cherry pits can give a character often described as almond-y, and which I perceive as also being cinnamon-y. So the inclusion of a bit of cinnamon, to “enhance the cherry flavor" (original French: "…cannelle de Ceylan pour relever l'arome de la cerise”) makes sense. In case you aren't aware, there are multiple types of cinnamon. Most cinnamon available, either ground or as sticks is Cassia cinnamon. Ceylon cinnamon sticks are visibly quite different and have more of a woody and complex characteristic. Ceylon cinnamon is also sometimes called "true cinnamon". Randy Mosher's Radical Brewing talks about the differences in these two a bit as well. Back to the krieks - I’m not aware of any commercial krieks currently being made with this sort of addition, but I think it would be cool to see at a light level. And, with producers expanding their current offerings, especially with fruit lambics, I wouldn't be surprised to see something like this in the future.

The Jordens text notes taking care in choosing which lambic to use for kriek production, with preference being given to more mellow lambic and lambic that is clear. The Q&A article states that 3 year old lambic is too old to use on its own, and gives this ratio for lambics of different ages: 20% 3 year old, 50% 2 year old and 30% one year old. The cherries are then left to macerate for 4-5 months in wood, with one source noting that some brewers agitate the barrels for a month after active fermentation. At this time, seeing square bungs in barrels was common. This made it easier to get fruit in and out. Some barrels with square bungs can still be seen in some lambic cellars, though they are a rare find compared to the common round-bunged barrels now in use.

Square bungs on the front barrels - at Oud Beersel.
After 4-5 months of contact time with the fruit, the kriekenlambic would be bottled and bottle conditioning would last around 6 months, with the bottles stored at 15-17° C (59-62.6° F) or cooler. In this time the bottles would develop carbonation. There is no mention of blending in young lambic or adding additional sugar solution for carbonation. The bottles were ready to drink after about 6 months, such that the final beer would be ready around the same time as the production of the next batch. Jordens notes that bottles would age well for up to 5 years.

Edit 22-Oct-18: It was helpfully pointed out that I didn't include any recipe info for the base lambic. I overlooked this as I've written about it before, but I should have included it here as well. These sources didn't specify, but the lambic would likely have been at least 40% unmalted then, perhaps toward 50%. The remainder would have been malted barley, with the malt pale but likely darker than modern pils and made from winter 6 row barley (escourgeon). Hopping would have been a mix of aged and current harvest hops. I've written a good deal about historic lambic hopping here so check that out if you want more info there, and see this post (with some other ancillary info here) for additional historic lambic production (though from a bit earlier - ~1850).

Fruiting Ratios
These sources recommend 160-200 g of cherries per L beer (1.34-1.70 lb/gal). To put this in to context, many modern krieks generally have somewhere between 200-300 g/L (e.g. Cantillon and 3 Fonteinen), though in some cases this can be as high as 400 g/L (Boon, Oude Beersel, some 3 Fonteinen). To confuse things, the fruit ratio can be and is calculated differently by different producers. For example, 250 g/L could mean:
  1. For 1 L of beer used in maceration, you add 250 g fruit. This can unambiguously be used, as it is in this article and as noted in this comment (in the context of fruiting ratios in the barrel of roughly 1 kg/L). But this may not be what is reported in the final ratio on packages.
  2. For ~1 L total volume, you have 250 g of fruit (or roughly 750 mL of beer + 250 g fruit, such that the aging vessel is 25% full of fruit) (e.g. here).
  3. For a beer and fruit mixture, in the final product after losses and blending, you get 1 L for every 250 g fruit used (e.g. here). If you aren't blending after aging, this is similar to method #1. The key key difference is losses when removing the lambic, and anyone that has aged a beer on fruit knows that the volume they get off of the fruit is less than what they put on. The first method doesn’t account for this. To me this method seems like the best for reporting final fruit ratios, but it is also the least direct from a brewing/fermenting point of view since you don’t reach the quoted ratio until the end when you know the volume you get off of the fruit and what you blend it down to (if you are blending).
Maceration in oak at 3 Fonteinen:
480 kg cherries and 500 L lambic.
At least the described ratio is clear in this historic article - 160-200 g per liter of lambic. Fruiting ratios are a bit smaller if expressed in methods 2 and 3 than method 1. For example, this historic kriek at 160-200 g/L by method 1 is 138-167 g/L by method 2.

Comparison with modern kriek
Fruit Ratio
Without knowing exactly which method different producers are using, and without knowing the losses assumed in these recipes to convert to method #3 above, it isn't possible to make an exact comparison with modern production. Even without this option, we can see that these fruiting ratios are on the low end or are lower than typically found in modern production (200-300 g/L or more, and with at least some producers using methods 2 or 3 from above to calculate ratios). In addition, with modern production, it is common to age beer at a higher fruit ratio and blend back to the desired level before packaging. There is no mention of blending back in these articles, but going with the assumption that there was no blending back of these fruit ratios from ~1907, these are still lower than modern usage.

I know of a couple modern beers with cherries from lambic producers that are around or below these ratios. Girardin Kriek is reportedly 150 g/L. Cantillon Kriek used 200 g/L cherries, which could be at the high end of this historic range depending on which method to quantify the ratio is used. Additionally, Cantillon Zwanze 2014 (technically not a lambic since it was Iris as a base) used a rate of 120 g/L. While there were other assertive characters to this beer on top of a spontaneous fermentation base (dry hopping and the stronger malt character of Iris), the cherries were definitely present. I think working at these lower fruit ratios are worthwhile and could be a good way to let other interesting characteristics come through while still having some cherry. Especially when the base has more character and/or when other additions are made.

In disclosure, this suggestion serves my own goals/preferences. I prefer a complex base lambic to a fruit-forward lambic. So if I am choosing something for myself to enjoy, it will almost always be unfruited lambic. And, in general, I have rarely had a fruit beer which I thought was better than (or even equal to) the sum of its parts (in fairness though, I don't know exactly what the lambic tasted like before going onto fruit). Not that I am unhappy to drink fruit lambic, but good lambic and good fruit are almost always better to me than good fruit lambic. However, given the general commercial popularity of fruit-forward beers over their base constituents, I may be in the minority here.

Spent cherries from a maceration in steel
at 3 Fonteinen.
Maceration & Lambic Age
These articles recommend an average lambic age of 2 years and 4-5 months maceration time. Modern production methods can vary considerably, and these historic lambic ages and maceration times are within the range of modern producers. Fitting with the lambic-cherry balance suggested by the lower fruiting ratio in the ~1907 recipe, the use of lambic on the older side suggests that the lambic portion of krieks from the beginning of the 1900s may have had more character. Presuming of course that this source is representative. For comparison, here are some modern commercial examples:

3 Fonteinen – Maceration lasts for around 6 months to 1 year (see here and here), depending on the specific product - the 3 Fonteinen Oude Kriek has a maceration around 6 months (see also herewhile maceration for the Schaerbeekse Kriek may last up to or more than 1 year (see also here, with bottle dates suggesting a typical maceration of 6-10 months assuming fresh fruit is used and harvest dates in June/July). The lambic used is roughly 1 year old.

Cantillon – Maceration lasts around 1-2 months and 2 year old lambic is used (see here and here). This is blended back with a small amount of young lambic for bottle conditioning in Cantillon Kriek, while Lou Pepe Kriek is primed with sugar for bottle conditioning.

Others - Boon reports using lambic that is 1 year old for their Oude Kriek, and Lindemans reports using lambic that is at least 6 months old and a maceration time of 6 months for their Oude Kriek Cuvée René. According to Lambicland by Webb, Pollard & McGinn, Hanssens uses 1 year old lambic and a maceration time of roughly 1 year to produce their Oude Kriek.

Tuesday, March 6, 2018

Bière de Saison (1905) recipe - turbid mash

This is part two of a pair of bière de saison recipes presented in Petit Journal du Brasseur, 1905. In the first post I gave a recipe for a bière de saison made from an infusion mash along with some general background info and more specific context for grains, hops, and how the brewing equipment would cause the process to be different from modern equipment. I'll skip repeating that background/context information here, so after a quick bit about turbid mashing then I'll jump into the recipe. This will be followed by a quick comparison of the two recipes to highlight the common ground which serves as a foundation of the beers as well as the room for variability, and some notes on hopping and how I've presented it in my modern homebrew recipe interpretations.

Two boil kettles at Brasserie à Vapeur.
Turbid Mashing
I've talked about turbid mashing a fair amount on this blog. So in order to avoid repeating too much of that, I'll skip most of that. If you're interested in some of those other posts, here are a few: Brewing Bière de GardeThoughts on Johnson 1918Thoughts on Evans 1905Homebrew Turbid Mash Petite Saisons. Instead I want to address a terminology question that I've been asked a few times regarding turbid mashes where a saccharification rest is performed after the turbid wort is added back. Basically the question is this: if you add the turbid wort back before a final saccharification rest, is this still a turbid mash (and/or why isn't it a decoction mash).

For starters, mashes where turbid wort is withdrawn and added back before a saccharification step are given the same name in French (moût trouble) as the turbid mash process that we may be more familiar with from traditional lambic - where the turbid wort is added back to the mash to be filtered through the grain bed after the first mash runnings are collected. And in the original sources in French these different mashes are not given different modifying descriptions. So the Belgian and French brewers treated turbid mashes where the wort is added back before and after the first runnings the same for terminology. Secondly, I think there is a key difference between decoction mashing and turbid mashing that could lead to a couple different distinctions in the outcome of following these processes. This is the transfer of only mash runnings compared to a mixture of runnings and grain to the kettle for heating.

Two boil kettles at Brasserie Dupont.
When transferring only mash runnings (and usually a significant amount of them) this should disproportionately remove enzyme activity from the mash. And then subsequently denature these enzymes when the runnings are heated. Perhaps with the remaining mashing process (prolonged saccharification rests) this doesn't end up being a problem. We at least know that this sort of mashing worked, so it must not have been too problematic. Also, when turbid mashing with adding wort back before a final saccharification step, the turbid wort usually skips at least one intermediate mash rest. So proteins may be less converted, whereas in decoction mashing the pulled mash is usually added back for the very next step, and therefore wort does not miss as many steps. Finally I think that transferring mash runnings would result in different color development than the use of a thick runnings-grain mixture in decoction mashing. Maybe these differences aren't all dramatic, but I think they still make turbid mashing distinct from decoction mashing and similar in many (but not all) respects to turbid mashing without a sacch rest for the turbid wort (as known from lambic production). Also, I think it should be noted here that not all lambic producers add the turbid wort back after collecting the first runnings.

As a bit of a side note, it would not have been uncommon for Belgian breweries to have multiple boil kettles in the 1800s and early 1900s, While this isn't needed for turbid mashing, for example turbid mashing where the turbid wort is added back before a final saccharification step (as outlined in the procedure here), it would make turbid mashing easier. The other main purpose for these kettles would have been for making a small beer alongside the normal brew with the later mash runnings. So while this recipe uses two kettles as outlined in the text, a second boil kettle could be helpful but not necessary when brewing a recipe like this at home or commercially.

OG: Not specified, but ~1.050 would be a reasonable assumption
100% Escourgeon malt
Alsace hops from the most recent harvest, 3 kg/100 kg grain

There is a lot in the mash that isn't specified (for example, the amount of turbid wort taken out). For this section I'll just present the mash as it is presented in the text and below, where I modify the recipe for a modern homebrew setup, I'll make some assumptions about the liquor to grist ratios and turbid pull volumes.
  1. Hydrate the grain to reach a temperature of 35° C (95° F). Rest 30 minutes.
  2. Remove turbid wort and send it to the second boil kettle.
  3. Infuse with boiling water (this is done by underletting in the commercial brewery) to reach a temperature of 53-54° C (127-129° F). Rest for 10 minutes.
  4. Remove turbid wort and send to the second kettle.
  5. Infuse to reach a temperature of 63-64° C (145-147° F).
  6. Take turbid wort immediately to the second kettle. Then rest for 40 minutes at this temperature.
  7. Boil the turbid wort for 20 minutes and add it to the mash tun (at the end of the 63-64° C / 145-147° F) rest to reach a temperature of 73-74° C (163-165° F). Rest 45 minutes.
  8. Lauter and collect mash runnings in the primary boil kettle. Sparge at 75° C (167° F).
The boil lasted 8 hours, with 1/3 of the hops added at the start of the boil and 2/3 added 30 minutes before the end of the boil. The brewer specifies their total amount of hops (40 kg) but neither their total amount of grain nor their batch size. The journal comments that they are therefore not able to address if this hopping rate is reasonable in their response, and suggests a total hopping rate of 3 kg per 100 kg grain. Based on the infusion recipe, if the OG and efficiency are similar, this would be just under 450 g per HL (0.6 oz/gal) for pre-boil wort, and something like 530-630 g per HL (0.71-0.84 oz/gal) for finished wort, depending on the cooling method.

A Baudelot Chiller. This one, at Liefmans, is quite large.
Smaller ones (not necessarily in use) can be seen at De Dolle or a Vapeur.
Again, as with the other recipe, the cooling method is not specified. But Baudelot chillers or coolships would have been the norm. If you are unfamiliar with Baudelot chillers, the hot wort runs down the outside of a stack of pipes while cold water flows through the pipes, leaving the wort exposed to air as it is cooling. The wort is then collected in a trough at the bottom and sent to the fermenter(s). Both Baudelot chiller and coolships leave cooled wort open and exposed to air. Though there are obvious important differences in time here, a Baudelot chiller is still not an especially sterile way to cool wort.

Fewer details are given for the fermentation of this beer than the infusion recipe, but I suspect it followed something similar to the infusion recipe (pitching around 20° C / 68° F, primary fermentation in barrels or open tanks followed by aging in barrels, and either option with aging on the order of 5 months before serving). The article mentions the beer would be served in July or August.

Modern Homebrew Adaptation
Batch Size: 19 L (5 gal) pre-fermentation wort
OG: 1.050
ABV: ~6%
IBU (theoretical, Tinseth): 24
Total Efficiency: 75%

4.1 kg (9.0 lb) Continental European Pale Malt
-This could be swapped for a 6-row malt, though if so it might be better to select a malt without a super high enzyme potential. You may be able to source something from a local craft maltster like the following: Double Eagle (see their Rustic Ale)Skagit Valley Malting (look for something made from Alba barley), and Riverbend Malthouse (I've heard they make a malt form 6-row, but couldn't find any info about it on their website).

The Q&A from PJB 1905 regarding this recipe.
100 g (3.5 oz) Stisselspalt (2.0 % aa). Given the specific mention of Alsace hops I think this makes the most sense, but other landrace hops or perhaps some more modern French hops with a similar profile would work well. You could adjust hopping rates down if going with hops with higher alpha acid levels. See also the notes at the bottom regarding hops and how I have modified these from the original recipe (and maybe adjusted down the hopping rate too far). The more I think about it, the more I think I've over-adjusted. But I'll keep this at 100 to keep it consistent with the other recipe. In brief, the original recipe calls for ~125 g (4.4 oz) of hops, so do that if you want to follow the original recipe more closely.

Mash: As noted above, this is an approximation of the recipe based on some volume assumptions (no addition or turbid wort volumes are noted). I think this should work based on past turbid mashes I’ve conducted, but I haven’t had a chance to try this out. So let me know if you run into any odd problems and you think there is an error in these numbers. I’m erring a bit on the wet side for the mash. Especially when it comes to the second and third turbid portions. You could remove more turbid wort, making the mash drier, if you wished. Without conducting it first myself I feel I should err in this way. But I think a drier mash/pulling more turbid wort at later steps would more likely reflect what was historically done.

As is always a good idea when conducting a new mash schedule (especially a turbid mash) or changing your equipment, it is best to have extra cold and boiling water on hand to adjust the temps as needed. And also it is a good idea not to max out you equipment to allow room for any adjustments.
  1. Dough in by adding 4.1 kg (9.0 lb) malt to 8.5 L (9.0 qt) at 38.3° C (101° F). This should give you 2.1 L/kg (1.0 qt/lb) at 35° C (95° F). Rest 25 minutes. You could also add water to grain, but with a drier mash I find it easier to add grain to water.
  2. Take the first turbid pull. I am guessing this would be around 1.7 L (1.8 qt), leaving you with around 1.67 L/kg (0.8 qt/lb) remaining in the kettle. Start heating the turbid pull, being careful not to scorch it.
  3. Add 3.7 L (3.9 qt) boiling water to the mash to reach 2.57 L/kg (1.23 qt/lb) at 54° C (129° F). Rest 10 minutes.
  4. Take the second turbid pull. I’m guessing around 3.0 L (3.2 qt) would be about right, leaving you with 1.84 L/kg (0.88 qt/lb).
  5. Add 6.3 L (6.67 qt) water at 78.3° C (173° F) to reach 3.34 L/kg (1.6 qt/lb) at 64° C (147° F).
  6. Immediately after this new temperature is reached, take the final turbid pull. This should be around 4.26 L (4.5 qt), leaving you with roughly 2.3 L/kg (1.1 qt/lb) in the mash tun. Heat the turbid portion to boiling. Let the mash rest at 64° C (147° F) for another 40 minutes.
  7. Add back the turbid portion. By my calculations this should be around 8.8 L (9.3 qt) and about 85° C (185° F) is the right temperature to reach 73-74° C (163-165 F). This should give you a mash around 4.5 L/kg (2.15 qt/lb). Rest here for 45 minutes. This may require letting the turbid wort cool a bit before adding it, or mixing some cold water in.
  8. Lauter and sparge as normal. Sparge water was listed as 75° C (167° F).
A schematic of the mash schedule, adapted for a homebrew scale with assumptions regarding volumes.
Boil: If you want to stick with this recipe then you're doing an 8 hour boil. This is quite long and you could probably shorten it if you wanted. Especially if such a long boil wasn't necessary to hit your target numbers. This will change melanoidin formation, but I think going for 3-5 hours would probably be a reasonable compromise here. And of course you could still make a beer following these guidelines with a 60-90 minute boil, but there would be some differences. Split the hops between the start of the boil - 1/3 of the total hop dose, or 33 g (again this can be adjusted based on aa) - and 2/3 of the hops, or 67 g, with 30 minutes left in the boil. See the note at the end about hopping rates in these homebrew recipes.

(Edit 16-Mar: As brought up in this FB discussion, doing a full-strength boil for 8 hours on a homebrew system might not work out too well. It is possible that in the original commercial brewery this was a simmer, though at the time at least some breweries were doing full strength boils for this much time. But on a homebrew setup, a boil of this length may not result in the beer you would want due to over-concentration of the wort and associated darkening/fermentability changes. So especially as a homebrewer, there is a strong case to be made for shortening this boil. I might start with something around 4 hours, and adapt from there.)

Cool the wort as you prefer - open in a kettle/coolship or with some sort of chiller.

Fermentation: I would take the same approach to fermenting this beer as I suggested for the other saison recipe. So that would include pitching a mixed culture that you like with yeast and lactic acid bacteria. I’d aim for something that includes some more hop-tolerant bacteria if you can. And I personally prefer to do mixed primary fermentations with everything in there from the start. Age the beer for on the order of 6 months, perhaps a month or two longer, before packaging. And make sure that the FG is stable. Oak would probably be for the ideal fermentation vessel, or at least for aging, but glass or stainless would also work fine.

Comparison of the Infusion and Turbid Mash Recipes
To me much of the important substance of both recipes is the same - 100% winter 6 row barley, roughly 3 kg hops from the general region (Belgian or Northern French hops) per 100 kg grain, a long boil (>5 hours) and aging until late summer/early fall (so about 6-8 months from brew to serving the beer). Both recipes also include a fair amount of hops added later in the boil where they could be more flavor-active, even though the beer will be aged for a while. In my experience with beers for aging with noble hops or similar, this can hold up pretty well. So I expect hop flavor from these hops does carry through to the finished beer. The infusion recipe lists 40% with one hour left and the turbid mash includes 2/3 of the hops with only 30 minutes left. These 'late' hops will see a fair amount of boil, which may come as a surprise to people used to more of the modern N American brewing process, but there should still be a flavor impact with noble-type hops at these boil and aging times.

While the two recipes call for basically the same total hop load, the splitting and timing of additions creates some interesting distinction. The infusion recipe calls for 60% of the hops to be boiled for at least 5 hours, and the remaining 40% are boiled for an hour. Additionally, the infusion recipe mentions Bavarian hops for the last hour. It looks like I may have forgotten to include this in the infusion recipe post itself, and that post will be updated to include this. This could be a non-trivial point for flavor, bitterness and microbiological progression, so I'm sorry about that. Other sources at this time mention these hops are more antibacterial than Belgian hops. This may be due to varieties as well as growing conditions or general hop quality. So this hop origin choice combined with the timing of the addition and the split favoring longer boils in this recipe may lead to a more bitter and less acidic saison, when comparing the two recipes. Furthermore, in the recipe calculations I've used a lower aa hop which would suppress the calculated IBUs, resulting in a beer that, on paper, seems less bitter than it should have been (see below for more on this).

On the other hand, the turbid mash recipe calls for only 1/3 of the hops to be boiled for more than 30 minutes. This would strongly favor carrying hop flavor through compared to the infusion recipe. Consequently this beer would likely have been less bitter (as is reflected in the theoretical IBUs, as the TM recipe calculated to ~30% less bitter than the infusion recipe) and could lead to a beer with more acidity along with the hop flavor. This shows the spread of saison at the time (something Yvan de Baets notes in his history of saison chapter in Farmhouse Ales), that historic saisons would have prominent bitterness or acidity.

On the mash side, I think the nature of these two mashes illustrates the brewing mentality to these beers pretty well. There is definitely not one mash to brew saisons, and these two mashes have some strong differences in terms of process. But there are also some core details that are fairly similar, and which are similar to some saison mashes still conducted today (see this post, for example). Both mashes have a rest around 53° C (~130° F) and saccharification steps that, especially for modern saison, are quite high - both include saccharification steps at or above 71° C (~160° F).  Furthermore, these were not short saccharification rests, so they definitely served a purpose. But the differences between these two mashes highlights some variability in process: doing a low temperature soak of the grain or not, spending an extended time in protein rest temperatures or just a quick rest, one or two saccharification rests, etc. Finally, the saccharification temp difference between these mashes and modern saison could reflect some differences in the brewing and the nature of saison. If you were aging it for 6+ months with a mixed culture then perhaps maximizing fermentability to Saccharomyces c. wouldn't be as much of an issue.

Hop, bitterness and my (possibly flawed) adjustments
For both of these recipes, I have dropped the hopping rate down a bit in my homebrew adaptations. There are many complicating factors that could make my decision to drop this down better or worse. To be honest, I forgot I had done it until I was writing this second post. One of the main things I was thinking about was hop aa levels increasing over time, mostly based on varieties but also a bit on quality of hops. But I hadn't considered that the hopping rates are referenced to malt amounts, and grain has changed quite a bit as well such that less grain is needed now to get the same extract. This would act to reduce the hopping rate per volume, and would result in my calculation of hopping rates being artificially low, so my adjustment to further lower the hopping rates may have been flawed. This may be counteracted a bit by my homebrew-level total efficiency of 75%, which is lower than many commercial breweries. (Edit 27-Mar-18) I also didn't consider that efficiency of hop use drops on smaller scales as well, which may suggest that I was overly-cautious in scaling back the hops as I did for this homebrew recipe.

Anyway, I'll leave the rates in these recipes as 100 g, but I feel less confident in this now. As I haven't had a chance to brew these, I can't see if I think the resulting bitterness from what I've listed is reasonable. If you want to try to come closer to the exact rates in the text that would be about 125 g per 19 L batch, and please report back if you go with this rate. It should be easy to adjust as the recipe is based on percentages at different times. As I noted above, I'm feeling less solid about my choice to scale the hops back a bit, but I think there are arguments to be made for and against this and it is hard to balance them all out with the uncertainty in each. Whatever you chose to do, I wanted to let you know my thinking and the uncertainty that remains.

Regarding the hopping rates and bitterness, I want to note a few things. First, this should be taken as a rough estimate. I’ve simply chosen a low aa modern hop, and variability in this value would result in a fair amount of variability in bitterness in the beer. Finally, there are other components that would contribute to perceived bitterness than isomerized alpha acids (e.g. tannins and beta acids). And by taking a larger amount of low acid hops (possibly poorly stored hops by modern standards) and putting them through a prolonged boil, I think you are going to get a higher perceived bitterness than the same amount of total alpha acid from a high aa hop. So I’d expect these beers to appear a fair bit higher than 30-35 IBU. And finally, as noted above, I've dropped the hopping rates by about 20% from those presented in the original recipes.

So on the whole I would treat both of these beers as more bitter than the theoretical IBUs presented here would suggest. And I would caution anyone trying to hit the same IBUs here but with high aa hops and trying to come out with a beers that would be perceived similarly or trying to brew with more historical accuracy, as the use of lower rates of high aa hops would probably further soften the beers. And I think this would move the beers further from their original nature. If you want to brew with high alpha bittering additions that's fine, as long as you recognize that this would create a different beer less in line with the history. And of course, there's nothing wrong with that.