Lesson 6 - Design of Fermentation Vessels

As we have seen, there are many different fermentation systems available for use and, therefore, we need some criteria in order to make an informed decision over which to choose.

Brewing has a long history and this is reflected in the variety of fermentation systems that have been developed over time. Traditional designs are often quite small by current standards, are made from traditional materials such as wood or slate, and often have strong geographical associations with particular beer styles. Linked to this are the different types of brewing yeast associated with particular beer styles, especially their cropping behaviour and how this impacts on fermenter design.

Many traditional fermenter designs continue to be used, often because it is considered that they have a critical influence on beer quality and in any case can be useful marketing tools. Some traditional designs continue to be built, although often with modifications to improve performance; for example, the conversion of open square vessels into closed versions to improve hygiene.

The development of the modern industrial brewing industry has been accompanied by the introduction of generally bigger vessels, usually closed designs, made from stainless steel. Some of these designs are linked to particular periods in the brewing industry. For example, the introduction of vessels such as the Rainier and Asahi types, both of very large capacity and designed especially for uni-tank processes, responded to the high demand for particular beer brands in the USA.

Currently, the cylindroconical fermenter is the most popular design. It can be used for most beer styles but is especially suitable for producing pilsner-style pale lager beers, which account for most of the world’s leading brands, using intensive processes such as high gravity brewing.

Criteria for fermenter selection are summarised in the following table:

Table: Criteria for selection of fermenter type