Wort Stripping: An Innovative Option for the Controlled Reduction of Unwanted Aromatics Featuring Optimised Trickle-Film Formation and Stripping Gas Utilisation

Abstract

There is a huge variety of different wort stripping systems on the market at present, utilising highly disparate technologies in order to reduce the amount of unwanted aromatics such as dimethyl sulphide (DMS), which are formed post-boil primarily during the whirlpool rest period. 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. In this way, the reduction in free DMS is currently running at approximately 40%. Other vendors utilise pressure reduction or thermal end-treatment. A new concept featuring a reduced footprint, easy retrofit options and without the use of vacuum or thermal energy is described below. 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. This allows a DMS reduction rate of up to approximately 70% to be achieved.