Fermentation is the process by which fermentable carbohydrates are converted by yeast into alcohol, carbon dioxide, and numerous byproducts. The byproducts have a considerable effect on the taste, aroma, and other characteristic properties of the beer. Fermentation is dependent upon the composition of the wort, the yeast, and fermentation conditions. There are two types of fermentation Systems, the "classical" and the industrial method. The "classical" method means the use of open or closed fermentation vessels and/or different vessel during fermentation and maturation. This process needs a lot of space, tanks, cooling Systems, fermentation and maturation time. All of this causes a lot of costs, so that the breweries tried to find new fermentation Systems. However, the factors that affect fermentation are time, wort temperature, volume, fermenter design, pressure, agitation and currents in the wort.

Survey of different fermentation systems