Why the Grade of CO2 Gas you are Using is Important

by Josh Pringle

One of the things we love to do at CO2Meter is talk about the new applications customers have shared with us by phone or email. We always say “now we have heard it all”, and then, someone calls with a new application. The innovation from our customers is endless.

Part of that innovation process for our customers includes questions like “How much gas should I use?” or “What concentration of CO2 do I need?” These are critical in every application that supplements with CO2 or gets the gas as a byproduct. The one question we rarely hear from customers but that is hyper-critical to success is “what grade CO2 should I be using”. That’s right – there are different grades or “purities” of CO2 that are produced and used. Do you know what grade gas you are receiving from your gas provider? Have you ever thought to ask?

To the right is a quick reference chart listing CO2 purity in descending order.

The biggest difference between the grades are the amounts and kinds of impurities that are allowable in the CO2. As you ascend the list the amount of impurities like ammonia, benzene, oxygen, carbon monoxide, and others allowed to be in specific grades of gas are lessened. While nobody wants to ingest benzene or ammonia those hydrocarbons are far more dangerous when working with lasers than with lagers.

The grading of 99.90% CO2 purity for beverage grade gases is now mandated by the Food and Drug Administration. The FDA regulations allow for the other .09% of the gas to be made up of other hydrocarbons.

Industrial applications like welding utilize 99.5% pure CO2. In welding, higher purity CO2 produces better welds because the process is heating less impurities in the process. Those impurities have been found to produce less stable welds.


No matter what your business or application is contact your gas supplier and ask:

  • What grade/purity CO2 are you delivering to me?
  • Can you provide me with a certificate that states the purity?

Any qualified gas provider will be able to not only answer those questions immediately but they should also be able to demonstrate the gas quality as well. Do not settle for purity any less than what your application calls for.

If you are unsure of your gas quality or call your suppliers analysis in to question you can contact an outside laboratory for third party testing services. You can contact www.airbornelabs.com as an example.

Also consider testing the water in your process as well. Brewers and vintners are keenly aware that water purity is just as important to end quality as the gas that they are using in your process. In fact, hydrocarbons like benzene are more likely to appear in the water in your process then in the gas you are using.


If you are interested in further details about beverage gas and its chemical composition please visit the International Society of Beverage Technologist, which CO2Meter, Inc. is a member of, at www.bevtech.org.

Posted by CO2 Meter on February 04, 2015.
Subscribe to our News feed Subscribe

More news