Carbonating my first brew, low on Co2 in tank - Home Brew Forums
Register Now For Free!

Home Brew Forums > Home Brewing Beer > Bottling/Kegging > Carbonating my first brew, low on Co2 in tank

Thread Tools
Old 04-27-2010, 02:02 PM   #1
Mar 2010
Cedar Park, Texas
Posts: 232
Liked 1 Times on 1 Posts


I am carbonating my first brew, and after a day, the Co2 tank is in the red zone (the regulator says to order more Co2), but the pressure is still at 10psi. I guess my question is if the regulator is really keeping 10psi or not when the amount of Co2 in the tank is low. To me it seems like it is keeping the 10psi, since I turned it down to 0, then back up to 10psi. Why does the regulator respond so poorly when turning the knob? I can turn and turn and turn and nothing happens. I have to go all the way down to 0, then back up.

Reply With Quote
Old 04-27-2010, 02:06 PM   #2
lschiavo's Avatar
Sep 2009
Upper Peninsula of..., Michigan
Posts: 4,910
Liked 1140 Times on 773 Posts

The pressure will stay in the line until you bleed the tank so your regulator will not respond just by turning the knob down. The high pressure guage is a much higher value than the low side. You may still have 10psi if the tank is nearly empty. Mine tank when full has about 600psi.

Reply With Quote
Old 04-27-2010, 02:38 PM   #3
Aug 2009
Twin Cities, MN
Posts: 2,509
Liked 36 Times on 35 Posts

Is your tank in the fridge? If so, even when full, it will read "red". Also, 1x 5# tank should last 4-6 kegs of carbonating and dispensing.

Here's a copy-paste of an earlier explanation of mine:

CO2 in a tank is mostly liquid, with a bit of vapor on top. The gauge is reading the vapor pressure, which you can think of like the pressure that the liquid CO2 is making while trying to boil. As you pull CO2 out of the tank (dispensing beer), more liquid CO2 boils into vapor to replace what you take.

The vapor pressure of the CO2 depends on temperature. So, at 70F, it will read like ~850 PSI, (going from memory here, but you could look these up). At 38F, it will read 500 PSI. It will CONTINUE to read that pressure until the tank is almost empty, at which point all of the CO2 liquid will have boiled, and the vapor pressure will start to drop as you use the last bit of vapor.

What this means is, your tank will stay at 500-600 PSI the entire time it's in the fridge, until JUST before it runs out, (before you use up all your CO2), at which point it will drop very quickly to 0 PSI.

The gauge is not like the gas gauge in your car. It basically only tells you if you have CO2 or not, not how much you have left.

If you don't use your CO2 for 20 years, (don't pull any pints), and don't have any leaks, it will stay at 500-600 PSI that entire time, (if in the fridge), and at any time if you remove it from the fridge it will jump back up to 850 PSI. As you use it, and keep pulling pints, and keep pulling CO2, it will stay at 500-600 PSI until it suddenly drops to 0, at which point you need a refill.
Itchy Dog Brewery.

(As of 10-24-2011)
Primary - Steppe 112 PA, 2x Monday RyePA
Aging - None :-(
On tap - Big Dog, Apfelwein, Steppe 112 PA

My invisible AG sculpture, with no actual sculpture and a tiny footprint.
My Kegerator goes offroading!
My Coors Home Draft dispenser for boating/beering on the go.

Reply With Quote
Thread Tools

Similar Threads
Thread Thread Starter Forum Replies Last Post
Can you brew all grain without the hot liquor tank? saffellm All Grain & Partial Mash Brewing 26 12-14-2009 09:53 PM
Just moved 1st brew to Brite tank. FoeKillerCreek Beginners Beer Brewing Forum 4 12-07-2009 04:45 PM
Force Carbonating without CO2 tank insaneferret Bottling/Kegging 5 04-10-2009 10:41 PM
Force carbonating with brew gas BrizolBrewer Bottling/Kegging 4 12-08-2008 12:38 PM
Hot water tank as a brew pot....? kenmc Kettles, Mash Tuns & Hot Liquor Tanks 4 03-31-2007 09:34 PM

Forum Jump