TECHNOLOGY
CO2
THE IMPORTANCE OF RECOVERED CO2 QUALITY
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n increasing number of breweries are investing in CO2 recovery technology, both in North America and around the world. Rising costs for liquid CO2, along with recent availability issues, have drawn serious attention to the importance of collecting and using CO2 from their own fermentation process. Much of the success in the craft brewing industry is related to producing artisan products that stand out from the many products brewed by the major breweries, which often have similar characteristics. By combining exceptional ingredients and their unique brewing processes, craft brewers offer beers and ales with flavours and aromas that please customers who are looking for something special. With this hands-on experience and knowledge, craft brewers are highly skilled at sourcing ingredients. While this depth of knowledge applies to ingredients like malt and hops, this is not always true for CO2. Craft brewers certainly know how to manage carbonation levels in their products to compliment the aromas and flavours they want but have not had to concern themselves with quality of CO2 until they start researching recovering their own CO2 – and it might come as a bit of surprise but not all CO2 supply is created equal.
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ISSUE 33 | 2024/25
WHEN IT COMES TO CO2 RECOVERY, THE QUALITY OF THE CO2 AND THE IMPACT THIS CAN HAVE ON YOUR BEER, THERE IS MUCH TO LEARN. THANKFULLY LENZIE KINYON, PROFESSIONAL BREWING CONSULTANT AND DALUM CONSULTANT IS ON HAND TO EXPLAIN MORE. It is imperative that craft brewers understand that when recovering CO2, they need ensure the system or technology they are considering can achieve beverage-grade CO2 so that their new recovered supply doesn’t contaminate the beer being produced and impact their ability to deliver a desired product to their patrons,
ucts, including oxygen that is in the headspace of each fermenter.
By moving away from purchased CO2, brewers are giving up the purification that is part of the commercial CO2 manufacturing process. Purification must now be done by the new recovery system being purchased. Liquid CO2 from that system must be pure enough to carbonate without adding unwanted flavours and aromas.
The chart provided here demonstrates the profile of the gas from fermentation at a brewery that has installed a Dalum CO2 Recovery Unit. On the left is the raw gas from fermentation coming into the CO2 recovery plant – as you move right you can see the non-CO2 components being eliminated as the purification and condensation process progresses. The stages include a water scrubber, compressor, dehydrator, and condenser.
The purity claims made by various recovery system suppliers should be compared to the purity recommendations for food and beverage use gases that are published by one or more industrial gas groups. These include the:
ISBT – International Society of Beverage Technologists EIGA – European Industrial Gas Association CGA – Compressed Gas Association
Brewery raw CO2 contains many organic compounds naturally formed during fermentation. These compounds include mercaptans, esters, aldehydes, sulfides, alcohols, and other fermentation prod-
Unless these compounds are removed by the recovery system, they may pass through and become defects in the flavour and aroma of the brewery products they come in contact with.
The result is CO2 purity of 99.98599.995% pure. Higher than ISBT benchmark meaning it’s high enough purity to use in beer, sodas etc. Dalum had a customer who tested both their CO2 from a commercial source and the CO2 from their recovery unit and the recovered CO2 actually tested at a higher purity which is reassuring for brewers exploring this technology. It’s difficult to appreciate the purity without understanding the risks associated with unwanted “contaminants “from CO2. Risks of “contaminated” CO2 include;
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