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P-38. Wort stripping: An innovative system for the controlled reduction of unwanted aromatics featuring optimized trickle-film formation and stripping gas utilization

Presenter: Roland Feilner, Krones Ag, Germany.

There is a huge variety of wort-stripping systems on the market at present, utilizing highly disparate technologies in order to reduce the amount of unwanted volatile substances, which are formed post-boil primarily during the whirlpool rest period. The focus lies mainly on dimethyl sulfide (DMS). Many of these systems achieve the desired reduction by generating large surface areas in the form of thin-film stripping. These processes are integrated in the copper, a separate tank, or directly in the whirlpool. Other vendors utilize pressure reduction or thermal end-treatment. A new concept featuring a reduced carbon-footprint, easy retrofit options, and without the use of vacuum or thermal energy is described . The innovative design enables the entire internal surface area of the external stripping tank to be covered with an even, turbulent trickle film. Besides generating an efficient, uniform, and turbulent layer, a stripping-gas control function is provided for maintaining the driving gradient between the gas and liquid phases and for influencing the quantity of the substances to be expelled. In industrial-scale trials, DMS reduction rates of up to approximately 70% could be achieved. The very flexible system can be integrated very easily in each existing boiling system, between whirlpool and wort cooling station. There are several rudiments to use the benefits of the new system. One is the reduction of the primary energy at wort boiling up to 50%, because it’s possible to reduce DMS additionally to the minimized boiling process. Second is the reaction regarding bad malt quality, resulting in higher DMS content after wort boiling by keeping the boiling system on a constant low energy level followed by wort stripping. Third is the reduction of the boiling time accessory to the minimized energy boiling process. The stripping gas control function enables reaction to specific malt quality terms and wort parameters at a very low energy level combined with high beer quality and unchanged beer character.

Roland Feilner (born in 1981) finished his apprenticeship as brewer and maltster, after which he studied food science technology in Weihenstephan, graduating in 2006 as an engineer. His career entry at Krones AG, Germany, started with membrane filtration of beer. At the same time, he worked as a process and development engineer for thermal product treatment, especially for juice and beer pasteurization. In addition, the vacuum degassing of beverages and juices was one of his main development areas. Currently he is responsible for new developments in wort treatment and process technology in the Krones R&D Division.