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Help! How much CO2 to carb a corny?

Good Morning
I just hooked up my first corny to tank and realized a drop in pounds, like 15. I’m pretty sure I don’t have any leaks. Is it normal to see this when setting a keg to carb? I’d assume some amount of decrease due to the CO2 xferring into the corny. How many pounds does it take to carb a corny? I’m off to work and don’t want to come home to an empty tank.

PS, thanks!

I can’t tell a 15lb drop on the high side of my regulator gauge.

You should be able to carb/serve 6-10 5 gallon kegs with a 5lb tank.

Thank you. When a beer is racked to a corny it’s flat. In 7-14 days with the “set it forget it” procedure, it’s carbed. During this transition, what would be the +/- number of psi that is utilized to get the beer to the drinkable carbonation level? There must be a certain amount of psi that transfers from bottle to the corny.

PSI isn’t transferred, that is just the pressure the tank is at due to the C02 vapor. Pounds of CO2 would be transferred, if you get 10 kegs carbed and served out of 1 - 5 lbs tank it’d be around a 1/2 lbs per keg to carb and serve. You’re not going to see the pressure of the tank change much if at all. It’ll move a fair bit with temperature as that will change at what pressure liquid C02 will transition to gas. The pressure on the C02 tank tends to stay the same until the liquid C02 is exhausted at which point pressure will drop. Ends up meaning once you see the tank side pressure dropping the C02 tank will be empty fairly soon.

To answer the question, it takes about 60 g CO2 to carbonate, and about 35 g to dispense. (Assuming 68°F fermentation and carbing to 2.4 vol at 12 psi.) So with no losses, you could carb and serve about 4-5 5 gal kegs per pound of CO2.

Like Flip said, the vapor pressure of the CO2 in the tank depends on temperature. The pressure won’t start dropping (unless the temperature drops) until the tank is ~10% full. Here’s a chart of vapor pressure as a function of temperature.

Here is a link to your carbonation chart that will tell you how mant pounds of CO2 to carb your beer at depending on temp of your beer while carbing, depending on the style and how many volumes of CO2 you want in your beer.


Happy to report no leaks. Pressure it maintained. First kegged beer is a week or so away from pouring the first pint. Thank you for all for your assistance. Mike

I set mine at 10psi. Beer is ready to drink in 7days. :cheers:

Fingers crossed on 7 days. I wonder if I swish the corny a few times a day if it will pick up speed.

Once the air is purged you can absolutely shake the crap out of it. I’m usually pouring after about three days.

[quote=“Steppedonapoptop”] just hooked up my first corny to tank and realized a drop in pounds, like 15.[/quote]Do you have the CO2 tank in the cooler with the beer? If so, the “drop” is just the CO2 getting cold and reducing pressure in the tank, but there’s no loss of gas.

My initial worry yesterday, was loss of gas. And that’s mainly due to a brain fart I didn’t want to mention. When I hooked up gas to the corny yesterday morning, I fit the hose onto the threads of the lock. I was in a hurry. So I sweated the whole day wondering if the kit included a barb/flare and when I got home, I found it, installed it and clamped it. Tight seals! Even a brain fart can be re-thunk…

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