What Is Food Grade CO₂?

Food grade CO₂ is carbon dioxide purified and tested to a level safe enough to put directly into food and drink. In practice that means at least 99.9% pure, with tight caps on specific contaminants measured down to parts per million and even parts per billion.

The number alone isn’t the whole story. What earns CO₂ the “food grade” label is proof: the gas has been sourced, purified, and tested to a recognized food-safety standard.

That’s the line between food grade and the cheaper industrial supply. Industrial CO₂ might look and behave identically coming out of the cylinder. It just hasn’t been held to the same purity limits or verified the same way, which makes it a bad bet for anything a person is going to swallow.

Which Standards and Regulations Define Food Grade CO₂?

In the U.S., food grade CO₂ falls under the FDA, which lists carbon dioxide as Generally Recognized as Safe (GRAS) in 21 CFR §184.1240. That regulation requires the gas’s purity to be suitable for its intended use and handled under current good manufacturing practice, rather than pinning a single number to it.

The hard numbers come from the Food Chemicals Codex (FCC), the compendium the FDA points to for food ingredient specifications. The FCC monograph for carbon dioxide sets a purity floor and caps a list of impurities, and meeting it is the baseline for selling CO₂ into food and beverage production.

Most suppliers go further than that baseline. The International Society of Beverage Technologists (ISBT) publishes a more granular specification, and it has become the working standard across the industry: a minimum purity of 99.9% and maximum limits for more than 30 individual impurities, including:

• Moisture: 20 ppm maximum, since water invites corrosion and off-flavors
• Oxygen: 30 ppm maximum, to protect flavor and shelf life
• Benzene: 20 ppb maximum, because a known carcinogen has no place in something people consume

ISBT is a voluntary consensus standard rather than a legal requirement, but it’s the one most producers certify against, because purifying a single stream to the strictest spec is simpler than running two. That’s why food grade and beverage grade are typically sold as the same product in the U.S. market, and why the certificate you want to see names ISBT.

In Europe, carbon dioxide carries the food additive number E290 and is approved under Regulation (EC) No 1333/2008, with the European Industrial Gases Association (EIGA) setting comparable purity and handling requirements.

Where Does Food Grade CO₂ Come From, and How Is It Purified?

Most food grade CO₂ starts as a byproduct of another industrial process, then gets cleaned up to hit spec. The most common sources are fermentation (the CO₂ that breweries and ethanol plants give off), ammonia production, and natural CO₂ wells.

The source matters because it decides what has to be purified away. Fermentation CO₂ is naturally fairly clean but can carry traces of whatever it fermented. A well or an ammonia stream brings its own set of possible contaminants.

From there, the raw gas runs through purification: compression, drying, filtration, and often activated-carbon and distillation steps that strip out hydrocarbons, sulfur compounds, moisture, and other impurities. Only after it’s tested against the standard does it get called food grade.

What Is Food Grade CO₂ Used For?

Food grade CO₂ shows up anywhere carbon dioxide touches something people eat or drink, including:

• Carbonation: the fizz in soda, sparkling water, and beer comes from food grade CO₂ dissolved into the liquid under pressure.
• Modified atmosphere packaging: CO₂ displaces oxygen in sealed packs of meat, produce, cheese, and baked goods, slowing spoilage and holding back bacteria.
• Chilling and freezing: as dry ice or in cryogenic systems, CO₂ flash-freezes and transports food at temperatures around −78.5°C (−109.3°F).
• Extraction: supercritical CO₂ pulls flavors, oils, and compounds out of hops, coffee, and botanicals without leaving a solvent residue behind.

In all of these use cases, CO₂ is in direct or near-direct contact with something consumable, which is why the standards are different from, say, a welding shop’s CO₂ requirements. 

What Are the Risks of Using Non-Food-Grade CO₂ in Food or Drink?

The risk is that industrial CO₂ can carry contaminants you’d never want in a beverage, and you often can’t taste, see, or smell them until they’re a problem. Because so much CO₂ is captured as an industrial byproduct, the raw gas can contain hydrocarbons like benzene, sulfur compounds, and other trace impurities depending on where it came from.

Food grade purification and testing exist to catch them. 

Industrial CO₂ is held to looser limits and never verified for consumption, so nothing confirms it’s clean enough to put in a drink.

At best, impurities throw off flavor: an off taste in a soda, a metallic note in sparkling water. At worst, they’re a real safety issue, which is why “CO₂ is CO₂” is a dangerous assumption on a bottling line or in a kitchen.

How Do You Know You’re Getting Real Food Grade CO₂ From Your Supplier?

Ask for the paperwork. A legitimate food grade supplier provides a Certificate of Analysis (COA) showing the batch was tested and meets ISBT or equivalent limits. No COA means no proof, and you shouldn’t assume the gas qualifies without it.

Beyond that certificate, a few things separate a good supplier from a not-so-good supplier:

• Traceability: they can tell you where the CO₂ came from and tie each delivery back to a tested batch.
• Standards compliance: they meet a recognized food-grade standard, like FDA GRAS (21 CFR §184.1240), ISBT, or CGA, and can point to the food-safety controls at the plant that back it up.
• Reliability: they keep you supplied at all times, because a bottling line or a kitchen that runs out of CO₂ stops running.

The paperwork tells you the gas is safe. The relationship tells you it will be there when you need it. You need both.

Food Grade Is Worth It

Food grade CO₂ costs a little more than industrial because it’s the version that is proven to be safe for consumption. On a bottling line or behind a bar, that proof is what stands between you and a recall, an off-batch, or a customer complaint, which makes it very cheap insurance.

Lawrence Haynes

Lawrence is the Marketing Director at WestAir Gases & Equipment in San Diego, CA