Priming kegs with sugar.. How much and why?

Homebrew Talk - Beer, Wine, Mead, & Cider Brewing Discussion Forum

Help Support Homebrew Talk - Beer, Wine, Mead, & Cider Brewing Discussion Forum:

This site may earn a commission from merchant affiliate links, including eBay, Amazon, and others.

DustinHickey

Well-Known Member
Joined
Mar 29, 2010
Messages
290
Reaction score
3
Location
Long Island NY
Hello,
I have recently started kegging and have one question. I have a kegerator with 2 taps and only room for 2 kegs in the fridge. This is all fine and good but since I always want a stout and an ale on tap I want to prime my kegs with sugar so I don't have to wait a week while a keg carbs up in the kegorator.

Ok, here's the question.

How much priming sugar do I use in a keg?

I have heard 1/2 the amount calculated for bottles and I have also heard to use the same amount as calculated for bottles. Some people report too much carbonation and some people say it works fine. I always use a priming calculator to determine the volumes but I am afraid of overcarbing because of hearing about this whole "use half the amount" rule.

First off, what is the reason behind using half the amount? I know papazian states to use less but why? pressure is pressure is it not? whatever pressure is in your keg when you finaly hook it up to the co2 shouldn't change because of the set pressure of the regulator. Does it have something to do with the 5PSI or so it takes just to seal the corny keg? Does it have something to do with the amount of head space in the keg as opposed to the total head space in a 5 gallon batch of bottles?

If so, this brings up another question. Say you rack from your fermentor into the keg and you only have about 4 or 4.5 gallons in the keg. How do you calculate priming sure then?

Also, say it takes me 5PSI to get one keg sealed and other times it takes 8PSI? How do you account for this added pressure to the pressure that will accumulate from the priming sugar?


I have only kegged 2 beers so far, one was a belgian specialty ale which Is currently pouring only foam right now, (force carbed it) I think I overcarbed this one because of a faulty pressure gauge reading. And another is a stout that I haven't tried yet. I primed this one with 77 grams of corn sugar for two weeks and am hoping that was the correct amount. It will run on beer gas through a stout tap.

Please let me know if anyone can help with this.

Thanks,
Dustin Hickey
 
you say you don't want to wait a week for a keg to carb with force carbonation. but it takes at least that long if not longer to prime with corn sugar.

if you rack only 4 or 4.5 gallons of beer into the keg you would add 4/5 or 4.5/5 of the amount of sugar you would for a 5 gallon batch.

if you pressurize to say 5psi at 50F. figure out how much carbonation that gives you and subtract that from the amount of carbonation your trying to add with the sugar. say for instance that 5psi at 50F gives you 0.25 volumes of CO2 (probably would give you less in real life) and you want 2.5 volumes of CO2 in your beer. 2.5 − 0.25 = 2.25 so you would calculate the amount of sugar for 2.25 volumes.
 
Hey Tipsy,
You misunderstood my first point. I can't force carb a new keg when I already have one running in the kegerator. I would have to wait until that one was done and then force carb for a week. Thus no beer for a week.

As far as the second part : but what is the correct amount for a 5 gal batch? 1/2 the amount calculated for bottles or the full amount? if half, why?

The last part makes sense. I will take that into account.
 
you say you don't want to wait a week for a keg to carb with force carbonation. but it takes at least that long if not longer to prime with corn sugar.

I think what he means is that he can only have 2 kegs on gas at any given time, and he wants to be able to change out kegs without waiting for them to carb.
 
I've only done 3 or 4 kegs, and all of them were primed with the normal amount of priming sugar for bottles (5oz). They were all lighter ales so I wanted a good carb level, but I didnt' think any of them were overly carbed at all. Just to note, I use the poor man's kegging rig - CO2 charger and picnic tap.
 
We've been talking about this over here:

https://www.homebrewtalk.com/f35/natural-carbonation-corny-keg-84178/

My understanding is that it isn't just about how much beer and how much CO2 you want, but that having all that beer in one big keg instead of a bunch of little bottles means you need less sugar and less CO2 produced.

I postulate that there is an equation that could be developed that would look something like this:

Required Amount of Sugar =

Desired Volumes of Carbonation X Amount of Beer in Container / Volume of Headspace in Container
 
Hi bad coffee. Ive used many calculators but none that are designed for kegging. Thats stricktly for bottling but people say to use less than that for kegs and im trying to figure out if its true and why.
 
I prime my kegs with sugar also, and started out using the same amount I would for bottling. I now use about 75% of the amount I would for bottling (using this calculator), and have been very happy with the results. The ~30psi of CO2 used to seat the lid will add some carbonation, and since I can always add carbonation to an undercarbonated keg very easily, it's good to err on the low side.
 
Has anybody tried to prime beer in a full sized keg? Not just corny kegs? Thanks

I primed a full size keg with the same amount of sugar I would use for bottling and it was WAY overcarbonated. I am currently kegging a batch with half the amount, I'll post the outcome.
 
Back
Top