Carbon Dioxide
The short version
The bubbles of every carbonated beverage — also used in modified-atmosphere packaging.
It's widely considered safe at the amounts used in food, so we mark it green. The Safety section below has the details.
Where it comes from
The fourth most abundant gas in the atmosphere. Food-grade CO2 is sourced from natural underground deposits, ethanol fermentation, ammonia production, or direct atmospheric capture. Used by humans since the 19th-century commercialization of carbonated water.
How it's used
The carbonation in all sparkling beverages — beer, sparkling wine, soft drinks, sparkling water. Also used in modified-atmosphere packaging to extend shelf life of fresh meat, produce, and baked goods. Used as a propellant in some food sprays.
Safety profile
Considered safe at all food use levels. CO2 dissolved in water gives carbonic acid (mildly acidic) — contributes to the slightly acidic pH of carbonated beverages. Excessive intake can cause bloating; no chronic safety concerns at typical exposure.
Physical & chemical properties
Colorless gas at room temperature, denser than air. Highly soluble in water under pressure — the basis of all carbonation. Slightly acidic in aqueous solution (pH ~5).
Regulation worldwide
Permitted globally without restrictive limits for food and beverage use.
Educational information only. Not medical or dietary advice.