Monday, November 25, 2013

Corking your homebrew

After promising few, if any, early posts on actual homebrewing process and recipes, here's a bit of my process. I know there are already some resources out there for folks who are interested in bottling their beers with a cork and cage, but here’s a pretty good rundown of my method. Hope it helps if this is something you are interested in doing.

Why would I want to cork and cage a beer? If you’re already sold on the desire to cork, you can skip down to the equipment section. For me there is one main reason – the ability to cork and cage a beer solved my never-ending search for enough high pressure (thicker glass) bottles. Bottle conditioning saisons and other high carbonation beers in normal beer bottles makes me nervous, especially when involving Brettanomyces and other higher attenuation and slow growing microbes that could slowly increase the CO2 level in a beer over time. I’ve never had any bottle bombs but I’d much rather put high carbonation beers into high pressure bottles. I had been collecting Belgian 330 mL bottles and the miscellaneous ‘normal’ cap size (26mm) 750 mL bottles (some of Upright’s beers, Jolly Pumpkin, Anchorage, Logsdon, etc.). However I've noticed with the thicker lip on these bottles that even though they are a normal cap size, I’d often get a bottle that I wouldn’t fully trust the seal of the cap and sometimes I would have to undo and re-cap bottles a couple times to get a proper closure. Corking solves this problem and I never doubt that a bottle is properly sealed.

In addition, I think it looks really good. To some folks it might not be worth it (~$0.35/closure, versus a couple of cents for a normal cap), and maybe if I had an inexhaustible supply of high pressure capped bottles and I never had any doubts with the seal, I wouldn’t C&C bottles. But since neither of those are the case I’m happy to cork. And I do like the way it looks. When giving beers to friends, it makes your homebrew look that much more professional. It shows that you really take pride in brewing and care about presenting your beer well. Alright, that’s probably enough rambling on why I like corking… On to the process.

Equipment: I have an Italian floor corker that was given to me by my friend Dave in my local homebrewing club (BrewVIC). I've seen the Colonna corker/capper in action and I would definitely recommend going for a step up to the Italian corker. You'll notice the standard #7 bung on the corker, but think any size bung will do, and the hole for the airlock fits perfectly with the corker. My corks and cages are from For a while I has using cages from my local homebrew shop but the wire was thinner gauge and was more likely to break while I was putting the cage on or taking it off. They also didn’t quite fit right, requiring me to hand-bend the tops for each cage, so I went back to the morebeer cages. The other tools/equipment I keep around when corking are a screwdriver for twisting the cage on and a large cookbook as a spacer (this will make more sense in a bit). The book idea was prompted by a piece of wood that my good friend Dylan used in his set up, and pretty much any solid spacer of about the right thickness will do.

Process: This corker isn’t designed for the most elegant process with Champagne and/or Belgian high pressure bottles because like most corkers it isn’t set up to leave some of the cork sticking out. But on a homebrew scale this is a pretty easy problem to get around. Sanitizing bottles works the same as you would do for normal bottling. I use starsan and a bit of foil over the top so I can shake them and keep dust out. I let my bottles dry in a tote with holes drilled in the top to hold bottles. This is another idea I’ve adopted from Dylan and I seriously recommend it. It cost me about $5 and 1 hour to set up (all you need is a hole saw and a drill, and maybe sandpaper to smooth the edges), and it works really well.

I put the full bottle in the corker with a book between the and the spring-loaded bottom holder. I spray the cork quickly with star san before putting it in the corker. This may or may not be important (or advisable), but I don't notice any problems with it and it makes me feel better about the cork. Once you start to lower the arm to cork a bottle, the bottom bottle holder is locked in place, which will be important when it comes to leaving some cork sticking out. And also, remove the foil! I've forgotten to remove the foil at this step and that's a real bummer.

Lower the arm until the bung reaches the the cork compressor. You'll notice the active depth of the cork pushing rod is adjustable and after a bit of trial and error you'll figure out what amount of external cork works best for you. I don't have a measurement for what I leave, but see the picture and description below. Then I raise the arm enough to remove the bung, but don't raise it all the way (this is important) and I remove the book. With the arm partially lowered the spring-loaded bottom will stay in place, giving you enough room to push the rest of the cork through while lowering the bottle.
Example of my level of external cork

Alright, so now we have the corking part of corking and caging done. On to the caging. One of the first things I noticed when comparing my early attempts to commercial cork and caged beers is that my corks didn't have the nice mushroom shaping. Part of this was likely due to the cork being in the bottle for a shorter time, but not vertically compressing the top part of the cork plays into it as well. So I started leaving a bit more cork sticking out. This also helped a great deal with removing the cork from the bottle. You may feel kind of like a fool when you excitedly show your friends your cork and caged homebrew, then spend forever trying to get the cork out and finally give up and use a corkscrew. Pushing the corks too far into the bottle proved to be the main culprit here (but increasing carbonation also helps when removing corks), so leaving more cork sticking out of the bottle helps in two ways. I leave enough cork out that the cage won't quite reach down below the lip of the bottle without vertically compacting the cork.

With the cage on the bottle, I pull the bottom cage loop out to the side while shaping the legs so they are where I want them to sit on the final bottle. You can adjust a bit later but it is easier to adjust them at this point. Then while pushing down with a pretty good amount of force with one hand, I twist the bottom cage wire clockwise in half turns while pulling the wire away from the bottle the whole time. Note for the vertical pressure part - in this interview with the Brewing Network (15 January 2006) at ~1 hour and 18 minutes in, Vinnie Cilurzo of Russian River starts talking about corking his bottles. They have a corking machine that mushrooms the corks for his normal bottles; however he has to cork the large format bottles by hand. In order to mushroom the cork for the 3L bottles, he pushes on the cork with a piece of wood under his entire body weight. So this vertical pressure helps the cork mushroom, also getting the cage low enough for it to sit under the lip of the bottle. Pulling the cage out while twisting helps the loops form cleanly. This looks better and it increases your chances of not breaking the wire while removing it. Generally I've heard recommendations of 6x1/2 turns. I kind of play it by ear and if the cage is still a bit loose I may do an extra 1/2 turn, or if I didn't twist the loops very cleanly I may only have 5. But too many and the wire may snap. Finally, bend the loop up out of the way and you're done!

My first couple runs were a bit more rough, with corks going a bit too far into the bottles and poor wire twisting causing some cage bottom wires to snap while I was removing the cages. But after a bit of practice and some cork depth adjustments you should have the process running smoothly.

Feb 2015 edit (see below as this is outdated):
I had to edit this post to include an excellent trick that I picked up from my friend Jeffery (the same one with whom I have this 60 gallon barrel) regarding mushrooming the corks. He pointed out that a bench capper does a really good job of this, simply push down on the cork with the capper for a few seconds. This will then hold its form long enough to cage. That means when you're twisting the cage you don't have to push down so hard (saving some sore palms, and I also had this fear that one day the neck would crack from the pressure while mushrooming the cork with my hand  leading to serious injury, and this prevents that as well) and you can focus on setting the cage and twisting it well. It looks better and is easier this way.

The finished product
Mushrooming with cage in place

Oct 2015 edit: I've been meaning to update this for a while. I only separated the mushrooming and caging for a short time. It is much easier to place the cage on and then mushroom with the bench capper as described above. Then I hold the bench capper arn down with my left shoulder/armpit and I have both hands free to orient the cage and twist the wire. This is the best way I've found to far to get a good looking finish and make sure the cork is properly mushroomed and the cage is properly in place.

Also, now I typically don't use the book and simply depress the pedestal with my foot after putting the cork into the bottle. And finally, I've gradually been leaving more and more cork out. Some day I should take a measurement, but the cage regularly reaches to around the middle or base of the upper lip of the bottle but not to the second cage lip without cork compression.


  1. The book and bung are really good ideas. I did it the hard way the first time, and put the corks in a bit too far. Which I really should have known better as you had mentioned you did that as well. I used a much larger "twister" than a screwdriver. I really can't see any advantage to more than 2-3 twists as the force of the cork is up not out. I think the bottle would explode before it untwisted due to pressure.

  2. Tim, I had a commercial beer where the cork shot and cage shot off as I completed undoing the first twist. That 6th turn was what kept it on. With all that said, the beer has some serious sanitary issues.

  3. I've had commercial beers go when the cage was loosened a bit as well. For some specific breweries, I always take the cage and cork off at the same time because I don't trust the cork to stay in long enough for me to get the cage off.

    Tim, I don't think I see a problem with doing fewer twists as long as the bottom loop is tight against the bottle, but I may be wrong. The force definitely won't be able to untwist the cage but as Dave said, if you get massively high pressures it doesn't take much slack in the bottom wire to release the cage. As you can see the screwdriver I used has a fatter end for exchangeable tips (it is a bit bigger around than a pen) so it needs about 6 twists to take up all the extra slack in the bottom wire.