What is beverage-grade CO2?

Beverage-grade CO2 is carbon dioxide purified to the standard required for food and drink, defined by the ISBT CO2 Quality Guidelines: a minimum purity of 99.9% v/v with strict ceilings on trace impurities such as benzene, total sulfur, acetaldehyde and oxygen.

Beverage-Grade CO₂ Analysis & ISBT Compliance

Beverage-grade CO₂ is carbon dioxide pure enough to carbonate food and drink. The standard is set by the ISBT (International Society of Beverage Technologists) CO₂ Quality Guidelines, which require a minimum CO₂ purity of 99.9% v/v and cap about a dozen trace impurities, benzene chief among them. ASTG builds the analytical systems that verify that specification continuously, on the live stream, with an audit trail. Our AirBreather platform measures benzene to 0.5 ppb, roughly 40× below the ISBT limit, and covers more than 40 impurities across the ISBT, CGA and EIGA specifications. It carries Coca-Cola approval NA-KO-102.

AirBreather CO₂ Analytical Systems

ASTG AirBreather CO₂ analytical system cabinet with touchscreen dashboard and CBAS remote laptop

AirBreather Systems™ was developed by ASTG at the request of one of the world's largest gas manufacturers, who wanted to modernize gas purity verification. It took five years to build, including two years of field trials and one year of in-service validation. The result is a robust, maintenance-friendly system that gives fast, reliable purity verification.

AirBreather uses new technologies for quality control, quality assurance and safety. Complete systems lower cost of ownership and increase throughput, with a performance envelope superior to any other technology.

Download the data sheet (PDF) · Get a quote

Watch: AirBreather Systems overview

What the ISBT CO₂ guidelines require

The ISBT guidelines are the commercial baseline for beverage-grade CO₂. They list each controlled impurity, set a maximum limit for it, and name the method used to measure it. ISBT is not a regulator, but a producer who cannot demonstrate compliance will struggle to sell into the beverage market. The headline limits:

Parameter	ISBT limit	Rationale
CO₂ purity	99.9% v/v min.	Process
Moisture	20 ppm v/v max.	Process
Oxygen	30 ppm v/v max.	Sensory
Acetaldehyde	0.2 ppm v/v max.	Sensory
Aromatic hydrocarbons (as benzene)	0.020 ppm v/v (20 ppb) max.	Regulatory
Total volatile hydrocarbons (as methane)	50 ppm v/v max.	Sensory
Total sulfur (as S)	0.1 ppm v/v max.	Sensory
Ammonia	2.5 ppm v/v max.	Process
Nitric oxide / nitrogen dioxide	2.5 ppm v/v max.	Sensory
Phosphine	0.3 ppm v/v max.	Regulatory

Two lines are set on safety grounds rather than preference: aromatic hydrocarbons, measured as benzene, at 20 ppb, and phosphine. Benzene is the limit that defines the rest. It is a known carcinogen, it is regulated rather than merely undesirable, and at 20 ppb its ceiling is among the tightest on the list. A system that resolves benzene with room to spare is usually one you can trust across the whole specification. For the full rationale, see What the ISBT CO₂ Quality Guidelines Actually Require.

How ASTG verifies beverage-grade CO₂

AirBreather measures the full ISBT picture on one platform, continuously. Speciated aromatics run on a dedicated GC-PID, which resolves benzene, toluene, ethylbenzene and xylene (BTEX) individually at 0.5 ppb each rather than reporting one combined 'total aromatics' figure. That lets you trace a contaminant back to its source. Sulfur and methanol are measured by FTIR (total sulfur to 0.020 ppm, methanol to 0.5 ppm), and oxygen runs on a dedicated sensor, because infrared cannot see it. The system reports more than 40 impurities across the ISBT, CGA and EIGA specifications and returns results in about four minutes. It runs on compressed air alone, with no carrier, span or calibration gases, and validates internally. It carries Coca-Cola approval NA-KO-102. See Beverage-Grade CO₂ Benzene Monitoring.

For CO₂ producers

AirBreather protects the certification your customers depend on. It runs continuous analysis at up to 40 sample points, uses Sample Safety Tech to prevent cross-contamination, and reads recycled and alternative CO₂ sources, which matters more as producers qualify new feedstocks against a tightening supply. It also uses less sample gas than any comparable system.

For bottlers

AirBreather protects quality at the point of use. Tanker offload runs through the DIP-1 driver interface, with automated fill panels and purity alarms. The Secure COA module issues certificates of analysis with full 21 CFR Part 11 audit trails, everything runs remotely through CBAS, and service intervals are one year.

Why detection margin matters

Meeting a limit on paper is not the same as proving it on a live stream, batch after batch. The value of a monitoring program is the margin between what the instrument can detect and the limit it is measured against. AirBreather's 0.5 ppb benzene detection sits about 40× below the 20 ppb ISBT limit. That headroom is what turns a pass from an assertion into a defensible result when an auditor asks.

Beverage-grade CO₂ FAQ

What is beverage-grade CO₂?

Beverage-grade CO₂ is carbon dioxide purified to the standard required for food and drink, defined by the ISBT CO₂ Quality Guidelines: a minimum purity of 99.9% v/v with strict ceilings on trace impurities such as benzene, total sulfur, acetaldehyde and oxygen.

What are the ISBT CO₂ quality guidelines?

They are the beverage industry's reference specification for CO₂ quality, published by the International Society of Beverage Technologists. Each controlled impurity carries a maximum limit and a defined analytical method, grouped by sensory, process and regulatory rationale.

What is the ISBT limit for benzene in beverage-grade CO₂?

Aromatic hydrocarbons, expressed as benzene, are limited to 0.020 ppm v/v (20 ppb) on regulatory grounds. ASTG's AirBreather detects benzene to 0.5 ppb, roughly 40× below the limit, with full BTEX speciation.

How is beverage-grade CO₂ tested?

Each impurity has a defined method. The most reliable programs measure continuously on the live stream (speciated aromatics by GC-PID, sulfur and methanol by FTIR, oxygen by a dedicated sensor), corroborate the safety-critical results, and issue an auditable certificate of analysis.

Does ASTG's AirBreather meet ISBT, CGA and EIGA requirements?

Yes. AirBreather measures more than 40 impurities across the ISBT, CGA and EIGA specifications and carries Coca-Cola approval NA-KO-102.

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