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Old 10-17-2012, 09:04 PM   #1
Nov 2011
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I'm just getting getting set up to start kegging and was wondering about using Corny kegs as a fermenter. Would appreciate any input/advise, pros & cons. Thanks!

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Old 10-17-2012, 09:13 PM   #2
Golddiggie's Avatar
Dec 2010
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I've done it before, but wouldn't do it again. For one thing, you'll get maybe 4-4.5 gallons out of a corny keg (5 gallon keg). For another, you need to modify the keg in order to ferment in it. At the very least, you pull the gas post, slip a short piece of tubing over the fitting, to secure the airlock to. Or you get one of the fermenting lids, or make one yourself. Personally, more trouble than it's worth.

I DO ferment in adapted sanke kegs though. I use tall 1/4 bbl kegs for my normal size batches (of beer). I have an adapted 50L keg for larger batches too. I also have several 1/6 bbl kegs that I use for mead and such (smaller volumes). I've adapted these to include a gas post on the top of them. I then use one of my sanke fermenter caps (my own design) so that I can ferment in them, have a thermowell in the middle, and then use CO2 to push the finished beer out of the keg. I have dip tubes cut to leave a certain amount behind in the kegs, so transfers are pretty easy.

If you can't score some sanke kegs for fermenting, then I would advise continuing to use what you are now.
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Old 10-17-2012, 09:28 PM   #3
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May 2011
La Porte, TX
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I do pressurized fermentation in corny kegs without any modifications to the keg.
You must use fermcap to do this or you will loose too much beer for this to be an effective fermentor.
I plug in my "blow off catcher" into the gas in line and install a spunding valve for pressurized fermentation.
Lots of threads on how to do this, I also use the same setup for a traditional fermentation just without the spunding valve and a little sanitized (or pre-boiled water if I want to top crop yeast) water in the "blow off catcher" to create an air lock.

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Old 10-17-2012, 10:19 PM   #4
Jan 2009
Boston, MA
Posts: 72
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I've probably done a dozen batches in cornies. Use some fermcap, remove the gas post and slip some tubing over the threaded post and attach an air lock, you'll be fine. Do it once or twice and see how it works for you.

The down side for me was cleaning the keg when done. Getting all that trub out was brutal.

I'm back to better bottles now.

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Old 10-18-2012, 12:31 AM   #5
Nov 2011
Posts: 100
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Guys, thanks for the input & info. I was wondering if their would be enough room in a corny to ferment a 5 gallon batch. I saw this blow off valve and it got me thinking about using corny kegs for fermenting.

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Old 10-18-2012, 01:34 AM   #6
Sep 2012
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Has anyone had any experience carbonating in one of these like a giant bottle conditioning?

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Old 10-18-2012, 02:43 AM   #7
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Jul 2009
Keller, Texas
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I've done some 3 and 4 gallon batches in cornys. I'm currently using one for a secondary for a sour beer. It's a very tight fit with five gallons. I have to be careful about opening the lid to avoid getting it in the beer.

With fermcap you should be able to fit a full five gallon batch in it.

Yes, cornys can be naturally carbonated.

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Old 10-18-2012, 05:24 AM   #8
helibrewer's Avatar
Nov 2011
Santa Rosa, CA
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Originally Posted by edds5p0 View Post
Has anyone had any experience carbonating in one of these like a giant bottle conditioning?
The closed pressure fermentation guys carb this way without having to add priming sugar or external CO2. There's an entire thread dedicated to this procedure.
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Old 10-18-2012, 06:53 AM   #9
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Nov 2010
utrecht, netherlands
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i'm now a habitual corny fermenter since my temp control system is based around one, and it fits perfectly with my 20L system
the size limitations concerns are valid but indeed you can maximize space with fermcap, that stuff is a dream, and by adding a bit of pressure with a spunding valve. i don't think cleaning is a problem at all; a rinse in hot water (with a hose) and an overnight oxyclean soak, all that gud comes right off
i either ferment with no pressure, with the out dip tube removed (replaced by an in tube) and a blowoff tube on one of the ball locks, or with the out tube in place and crank up the pressure towards the end to carbonate in the keg, then pressurized transfer to a lagering/serving keg.

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Old 10-18-2012, 02:43 PM   #10
Jul 2010
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I just did this for the first time 2 weeks ago. Instead of ferm cap (didn't have any) I split my batch into two 5gal cornys. I have slightly under 3gal in each keg. I pulled out the liquid dip tube and post, and just put 1/2'' ID tube over the liquid outlet, and secured it with a hose clamp. With about 2 gallons of head space, I got no blow off out of the keg.. seemed to work great. No permanent modifications were made to the kegs.

My problem now is trying to figure out how to get the beer out, and leave the yeast cake in tact so I can then wash the yeast. Tonight I will attempt to push it with CO2. My plan is to bend a dip tube (this is where I'll be guessing though since I have no idea how thick the cake is) so that I will just collect the beer at first. Then I will take a straight dip tube, insert it, add my sanitized "wash" water to the keg, swirl, and hopefully be able to push the yeast out. I'm not sure if this will work as smoothly as I'm hoping for though.... I'd love to hear some tips from the guys who have done this before.

As of now, I would definitely continue to use kegs. I brew by myself for the most part, and lifting 2.5-3 gal in a keg over the wall of my chest freezer ferm chamber is a lot easier then lifting a full glass carboy.

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