Whether it’s soda, sparkling water, or the more recent popularity of carbonated coffee, tea, or juice, CO2 is essential for creating those bubbles necessary to ensure a beverage is consistent and safe.
Don Pachuta, PhD, president of Airborne Labs International, Inc., Somerset, N.J., says the quality of CO2 used in beverage applications was historically often overlooked with minimal testing done. This changed radically, however over the last 20 years.
“Robust CO2 quality control not only ensures the desired pleasurable sensory impact of the beverage but also for its freedom from potential ‘health impacting’ harmful effects that can arise from various undesirable impurities in the CO2,” he says.
Moreover, as more “non-traditional” sources of CO2 are explored and employed, the issues of CO2 quality maintenance become more challenging as new potential source-specific impurities must now be carefully studied, and related impurities identified, removed, monitored, and subsequently controlled by appropriate purity standard-setting bodies. These include such as the Compressed Gas Association (CGA), International Society of Beverage Technologists (ISBT), European Industrial Gases Association (EIGA), FDA, and other governmental or international standard-setting groups.
“It must be understood that all CO2 quality assurance processes involves a complex, multistep supply-manufacturing-delivery-storage-beverage manufacturing chain, which starts with the composition of the original feed gas source of CO2 through its final infusion into a beverage product,” Dr. Pachuta says. “For reasonable economics, CO2 supplies need to be produced and stored relatively local to their end users. The key is that many diverse and new non-traditional types of possible localized CO2 sources are continually being evaluated for economic, consistent, and sustainable supply reasons.”
Recent reported shortages of beverage-grade CO2 this last summer in Europe and other areas highlighted the need for a more stable and local CO2 production picture.
Guidelines in Place
The CGA publishes several industry consensus standards on the production, storage, and transfer of CO2. CGA published its first CO2 commodity specification in 1973 and periodically updates it and other CO2 standards and guidelines to address new uses and feed gas sources. These specifications provide limiting characteristics and identify recommended testing methodologies for the analysis of potential contaminants in liquid, gaseous, and solid CO2 for various uses.
ISBT has a set of guidelines that establishes production and feed gas considerations, finished product impurity levels, and analytical method recommendations for beverage-grade bulk CO2.
Larry Hobbs, executive director of ISBT, says the CO2 guidelines established by the organization’s Beverage Gases committee were created by a group of experts that included members of the beverage industry as well as the suppliers and the producers of CO2.
“Their work took several years to complete and the result has been to improve the quality and consistency of CO2 used in the beverage industry,” he says. “As a general practice, suppliers provide certificates of analysis upon delivery for ingredients, including gases such as CO2 to certify that the material meets the standards established in the contract with the customer. These are backed up by a lot of analysis by the shipper as well as whatever internal sampling and testing programs the customer may have.”
Major gas suppliers like Air Liquide and Airgas (which recently merged), Linde and Praxair (which recently merged), and Matheson produce and sell CO2, and all perform quality testing and periodic third-party testing at approved labs.
John Willenbrock, technical manager for CGA, says CO2 is manufactured in accordance with a company’s standard operating procedures that are developed to meet customer expectations and, in the U.S., for compliance with the Food Safety Modernization Act (FSMA) and FDA’s implementing regulations. Interestingly, CO2 is not only an ingredient in beverages but is also classified by the FDA as a drug among other uses. That’s why it’s important the criteria meet the CGA’s standards identified for beverages and also with CO2 standards for other intended uses.