6 Common CO2 Questions Answered

CO2 Regulator Single Gauge

CO2 is an essential factor to consider when dispensing draft beer and it’s typically the component that has the most questions associated with it. It’s unclear why people are easily intimidated with CO2, but it could be because chemical compounds and subscripts remind them of their high school chemistry class.

Without getting too technical, here are the answers to the most frequently asked CO2 questions:

1. How do I know what pressure my CO2 is set at?

Your regulator, which is the component that connects the tank to the air hose, will have either one or two gauges on it. If it only has one, then that’s the one you’re looking for. If it has two, look for the gauge that shows a range of about 0-60 PSI (pounds per square inch). This will be your regulated pressure gauge. The number the arrow is pointing to on this gauge is how much pressure is being delivered to your keg.

2. How do I know how much CO2 is left in my tank?

This is why it is worth considering a double gauge regulator. A double gauge regulator has a regulated pressure gauge as well as a high pressure gauge, which measures the amount of CO2 left in your cylinder. Without a double gauge regulator, it is a bit of a guessing game. Rather than waiting till you completely run out, it is good to know how many kegs can be dispensed per CO2 tank to know when the best time to refill is.

3. How many kegs can I dispense before needing to fill my CO2 tank?

If you’re using a 5lb. CO2 tank, you can dispense 2 to 4 full sized kegs before having to refill. The cooler the ambient temperature, the closer you’ll get to 4.

4. What pressure should my CO2 be set at?

Most American breweries advise for a CO2 pressure between 12-14 PSI. The brewery or distributor you received your keg from should have a pressure recommendation, and if you receive your keg from a third party, it’s best to call the brewery and ask. An inaccurate pressure can result in either under or over carbonation, which translates to either flat beer or an overly foamy beer.

5. Should my CO2 tank be inside or outside of the Kegerator?

Although it doesn’t make a significant difference either way, most CO2 tanks are mounted outside of the refrigeration compartment. This allows for a better use of space inside the refrigerator to fit kegs. Distance between the tank and the keg is not important as long as you have a reliable air hose. What is important is that your CO2 tank remains upright and is kept away from heat sources.

6. Where can I get my CO2 tank filled?

Local welding supply stores, locations that fill fire extinguishers, local home brew shops, and sporting stores that sell paint ball guns are among the most likely places to get your CO2 tank filled.

Diagram for Regulating Keg Compression:

Hopefully this answers all of your CO2 questions. If not, please leave your question in the comments section below and we’ll answer you as soon as we can. Now, let’s get back to what’s really important – drinking beer.


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Jeff Flowers

About Author

Jeff Flowers has been a self-described beer geek for over a decade now. When he's not chasing his daughter around, you can usually find him drinking a fresh brew and wasting too much of his time on both Google+ & Twitter.


    • Jeff FlowersJeff Flowers says

      Hi Bob,

      Yes, that is correct. Once you have everything set up and all of the lines have been securely attached, you will turn the CO2 tank on, find the right pressure for your beer and keep it that way until your keg is empty.


  1. jeff odonnell says

    I left my co2 tank on for a week or so and i went back and and now the full co2 tank is completely empty. Where are the easiest ways to detect a leak?

    • Joe Domiano says

      Ive had the same issue before. For me since Im doing homebrew kegging, I find that the gas ball locks dont have a perfect seal and if they are not hooked up to a keg, they are a source for a leak. I usually put the valve in the off position just after the regulator. I forgot to do this last week as i was cleaning my beer lines and kegs and now my CO_2 is out again :/ Gotta stop by the welding supply store to refill so I can keg my new batch and carbonate it.

    • dennis says

      Yes but you must (Must!!!) Remember to turn the gas back on or you’ll pump the native Co2 out of the tank and all you’ll have is a keg of flat beer.

    • dennis says

      Sure do. Hard plastic if it came w/ it silicone or rubber otherwise. Gas rated Teflon tape on the threads can’t hurt..

  2. Brandon Roberts says

    I wasn’t sure about where I was supposed to set my co2 at. Which this site helped me figure that problem out. Also, I’m glad you talked about using a double gauge regulator in order to figure out how much co2 is left in the tank. Thanks a ton! You were a big help.

    • Joe Domiano says

      I suggest using the brewersfriend app to determine the amount of CO_2 pressure needed for the type of beer you have on draft. Different beer types should be carbonated at different PSI or volumes of CO_2 per mL. Temperature plays an important role in this so know what temperature your kegerator stores liquid at. You can do this by putting a thermometer in a glass of water and let it sit in there for a few hours to see what temp it equalizes at.

  3. dennis ducker says

    Does C02 in a 5 lb tank go bad? I have a tank that has had C02 in it for approximately 10 years…..NEVER BEEN USED. Don’t want to infuse anything bad into a fresh keg of brewski!!

  4. Troy Duron says

    I have a double gauge regulator and the high pressure gauge is right at 500 psi (the gauge goes up to 3000.) The beer is coming out too foamy, does this mean my co2 is running low?

  5. Jenny says

    Did the soapy water trick looking for a leak in the co2 line. Couldn’t find one. Also had the regulator checked, and it’s fine. Co2 lasts 24-48 hours and I’m on my 4th bottle. its brand new. Please help!

  6. alvaro says

    how i safely empty a 456gr co2 tank for sending via airplane in mail?

    which are the procedures for sending a co2 tank via mail airplane?

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