sugar for priming keg
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ShutTheFermenter
Active Member
I've never used sugar to carbonate in a keg but when I bottle I use 5oz per 5 gallons.What was your bad luck with CO2?
jmcquesten
Well-Known Member
That is too much.
I chilled keg to 5 deg then set gas 35psi and rolled and wobbled keg around til it stopped gurgling waited couple hours . It just did not taste good.. plenty of head though
ShutTheFermenter
Active Member
Was it a new recipe? You're sure everything was clean and sanitized?
V-Fib
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The issue might be force carbing it. When I keg carb with CO2 I set my PSI to my serving pressure and let it sit for 7 to 14 days. I also carb with corn sugar and just use an online calculator. When I do that i still let it sit for 7 to 14 days at room temp.
I'm trying sugar at the moment with one keg and another is in fridge cooling for another crack and fast carbing.
For priming in kegs use about half the sugar you use for bottling.
Can you explain why you would do this? The headspace to beer volume ratio is pretty much the same for a full keg vs. a bottle (about 6%.) How do you generate the same amount of CO2 with half the sugar, just because it is in a keg?
I don't mean to single you out, as I have seen this advice all over the place, but no one can explain the basis for the recommendation.
Brew on
This is the easiest way to over carbonate a keg, and is probably what happened to you. Excess carbonation can give your beer an unpleasant "carbonic bite."
If you want to burst carb by the "shake, rattle & roll" method, with no chance of over carbonation, use the pressure from the chart that gives you the volumes of CO2 you want at the current temperature of the beer.
Brew on
Can you explain why you would do this? The headspace to beer volume ratio is pretty much the same for a full keg vs. a bottle (about 6%.) How do you generate the same amount of CO2 with half the sugar, just because it is in a keg?
I don't mean to single you out, as I have seen this advice all over the place, but no one can explain the basis for the recommendation.
Brew on
I don't know, really. It is, as you say, common advice so it gets passed on. If it is not related to head space then perhaps bottling causes more of the CO2 already in the beer to come out of solution due to the extra handling.
Ales usually have about 0.85 volumes of dissolved CO2 in them at the end of fermentation (varies with final ferm temp.) To get 2.5 volumes of final carbonation, you need to add enough priming sugar to create 2.5 - 0.85 = 1.65 volumes. If you only put in half the sugar, you would only create an additional 0.825 volumes of CO2. If you could make a case that the extra handling of bottling vs. kegging eliminated ALL of the residual CO2 in the starting beer, then to get 2.5 volumes of final carbonation, you have to prime with enough sugar to create 2.5 volumes. However, all of the priming calculators I have seen recommend only enough sugar to generate about 1.6 - 1.7 volumes, so the bottle priming calculators are NOT assuming any significant loss of residual CO2 due to "extra" handling.
Brew on
Doug, your analysis sounds right. Myth busted? The only other thought I have is that it is an attempt to avoid yeast build-up in the keg. At least with kegging we have the ability to change the CO2 level post packaging which eases the need for the same level of precision needed for bottling.
timcadieux
Well-Known Member
There are lots of carbonation calculators available to help you figure this out.
