CO2 Inline Polishing Filters for the Beverage Industry

Carbon Dioxide is the only industrial gas used as an ingredient in the production of carbonated beverages. It is therefor subject to the highest quality requirements by beverage manufacturers due to the potential risk of contamination of the beverage by the gas.

Carbon Dioxide is produced as a by-product (or co-product) of a chemical or industrial process, fermentation, combustion or separated from a waste stream. It can also occur naturally from underground geo thermal activity.

All sources of carbon dioxide have source specific impurities that can be present in variable concentrations, the levels are reduced by gas purification plants operated by Industrial gas producers, however small traces can still be present. It is also possible that contamination of purified product can occur through handling and distribution or cross contamination of the product.

Out of specification carbon dioxide can have a detrimental impact on the flavour, stability and appearance of the beverage as well as a negative consumer experience due to an off taste or unpleasant aroma.

In recent years beverage producers have taken steps to protect themselves from this quality risk. In addition to established quality control requirements such as Certificate of Analysis and Conformity, as well as detailed analysis of the finished product, beverage producers have installed multi-stage CO2 polishing filtration systems in their own plants after the CO2 has been vaporized.

These create an in-plant multiple barrier to stop the trace impurities from entering the beverage production process, they also protect the brand owner from quality incidents that could occur if there has been a failure in the external supply chain's quality system.

These 5 stage filtration systems are cartridge based that use a modular design philosophy, this overcomes many challenges with loose filled carbon filters. Cartridges are easy to replace, clean to handle and do not require any special tools or extraction equipment. This makes them easy to maintain by the beverage producer. The modular design also makes it convenient to increase or decrease in increments as the need for greater demand flow and capacity increases or decreases. An optional stage 6 provides further filtration performance down to sterile levels, this is suitable for brewing operations that share their CO2 with a soft drink producer.

Recently a new manufacturer Sure Purity Ltd, launched the Carboguard series of CO2 polishing filters, these feature further improvements to the multi-stage filter performance of other manufacturers. The range of potential impurities is vast and continues to grow as new source specific impurities are discovered. The Carboguard range provides the greatest level of protection from the widest range of potential impurities, thus offering the greatest peace of mind to beverage producers of carbonated beverages. These systems not only protect from the more commonly found impurities but also some of the newer source specific impurities being discovered. High levels of protection of up to 10x the limits set by ISBT, EIGA and CGA is possible with the CARBOGUARD system.

Carbonyl Sulfide is a particularly troublesome impurity and difficult to remove with traditional purification, Sure Purity led a development team to create an advanced adsorbent material that permanently removes COS, in the event that traces remain in the CO2 being delivered the levels post polisher were found to be undetectable using the latest Sulphur analytical methods and equipment.

This work has led to two major soft drink brands approving Carboguard for use by their bottling operations globally.

Ultimately the move to include multi-stage CO2 polishing filters provides the peace of mind beverage manufacturers can rely on and trust.


Gary Robson

Managing Director

Sure Purity Ltd

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