Natural Carbonating 2.5 Gallons in 5 Gallon Keg

[beerdrinker]

I'm wanting to start naturally carbonating my kegs for a few logistical reasons on my end. However my latest batch was only 2.5 gallons vs the normal 5 gallon batch.

With the extra head space I'm concerned it might pose some issues. First with the amount of priming sugar needed, would additional sugar be needed to hot the same carbonation level. Second, would the natural carbonation process be able to consume the extra oxygen in the headspace, or would I need to hook up the CO2 and purge the oxygen.

Cheers!

[beerdrinker]

Hey, if I'm naturally carbonating in a keg for the sugar need to be boiled?

I know with bottling the sugar needs to be boiled so that its balanced bottle to bottle. However in the keg I don't see the need of boiling the sugar, has anyone had success jet putting in sugar?

[AsthmaticBowl]

Hey, if I'm naturally carbonating in a keg for the sugar need to be boiled?

I know with bottling the sugar needs to be boiled so that its balanced bottle to bottle. However in the keg I don't see the need of boiling the sugar, has anyone had success jet putting in sugar?

I believe the main reason for boiling the sugar in a small amount of water is for the purpose of making sure that any contaminants are killed off. Other than limiting that risk there is no other purpose to the boiled sugar solution.

-Not sure about your head space question, but personally I would just cut the priming sugar in half and if your carb level is a little low once it has primed, you always have the option of forcing in a bit more, since it is already in the keg. Better to be a little under in this case than a little over.

[Stinkfist]

Thinking about it quickly I would think you would need to double the sugar... PV=nRT. You are only changing the volume in the equation.. The issue is how much of the volume is liquid and how much is air, either way you will need extra sugar to account for the extra volume so you keep the same pressure. If it was me I would probably put in about 1.75 X the amount you were going to put in. But again it is an estimate. Good luck

[BDawg]

No, it's actually a SMALLER amount of sugar needed when carbonating in a bigger container.

The guy in this old thread on Homebrewtalk does it often and uses 1/3 the normal amount.

http://www.homebrewtalk.com/f35/using-c ... keg-80656/

[Stinkfist]

No, it's actually a SMALLER amount of sugar needed when carbonating in a bigger container.

The guy in this old thread on Homebrewtalk does it often and uses 1/3 the normal amount.

http://www.homebrewtalk.com/f35/using-c ... keg-80656/

I am assuming this is because he first puts in 30 Psi to seat the lid...if that is the case I could see why you would use less