ISBT and EIGA requirements for beverage-grade CO₂

For a bottler, CO₂ is a food ingredient rather than a technical gas. Which parameters are limited, why a supplier certificate is not enough, and what a minimum laboratory looks like.

Carbon dioxide that goes into a drink is a food ingredient. It is judged not only by purity but by a list of trace impurities, some of which are limited at parts-per-billion level because they are detectable by taste and smell long before they are dangerous.

Who sets the requirements

• ISBT, the International Society of Beverage Technologists, whose specification is the de facto industry standard for beverage CO₂.
• EIGA, the European Industrial Gases Association, whose document is aligned with ISBT and is what European suppliers refer to.
• In Ukraine, the relevant DSTU standards and food safety requirements under HACCP apply on top of that.

What is actually controlled

The typical set of limits looks roughly like this. Exact values should always be taken from the current revision of the specification, since it is periodically updated.

• CO₂ purity — not less than 99.9% by volume.
• Moisture — up to about 20 ppm.
• Oxygen — up to about 30 ppm.
• Carbon monoxide — up to about 10 ppm.
• Total hydrocarbons — up to about 50 ppm calculated as methane, with a tighter limit on non-methane compounds.
• Benzene — at the level of tens of parts per billion.
• Sulphur compounds — around 100 ppb in total; these are what give the classic off-smell.
• Acetaldehyde, ammonia and nitrogen oxides — units of ppm and below.

Why this matters even if you do not produce CO₂

Responsibility for the finished drink lies with the bottler. A supplier certificate confirms the quality of a particular batch at the moment of shipment; it says nothing about what happened during transport, or whether the product was loaded into a tank that previously held a technical grade. That is why incoming inspection is a separate control point in a HACCP plan, not a formality.

A minimum laboratory

• CO₂ purity analyser.
• Moisture or dew point analyser.
• Oxygen analyser.
• A sampling system for both the liquid and the gas phase — sampling from the wrong phase is the most common source of false results.
• Calibration gases and consumables, with a schedule for verification.

A full set covering every ISBT parameter is expensive, and not every plant needs one. A common approach is to keep continuous monitoring of the critical few parameters on site and send samples to an external laboratory for the full profile at an agreed frequency.

How often to test

The practical scheme is layered. The critical parameters — purity, moisture, oxygen — are checked on every incoming delivery, because that is where contamination enters. The full profile, including benzene and sulphur compounds, is ordered from an external laboratory at an agreed interval, typically quarterly, and additionally whenever the supplier or the source of the gas changes.

What to do with an out-of-spec batch

• Do not connect the tanker to the tank until the incoming result is in — a rejected batch mixed into the tank contaminates the whole vessel.
• Record the result, notify the supplier, keep the sample.
• If the product is already in the tank: stop take-off, decide with the supplier on emptying and cleaning, and check the finished goods produced since the last clean result.

This is exactly the scenario an auditor asks about, and having a written procedure for it matters more than the number of analysers on the bench.

We help define the mandatory set for a specific process, supply the analysers and sampling systems, and audit an existing laboratory against ISBT and EIGA requirements.