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The addition of hops also serves to precipitate out undesired protein material which is then removed in the whirlpool, to stabilize the head in the finished beer and to improve the shelf life of the product. After a period of boiling of about one hour, the original extract value is calculated - this is the ratio of dry material to liquid - and the hot wort (cast-out wort) is cast out via the whirlpool. Protein components that have precipitated out within the wort pan settle out in the whirlpool in the form of a hot trub cone.
Cooling of the wort by means of a heat exchanger is necessary because the wort in the whirlpool is still almost at the temperature at which boiling is performed. The heat exchanger is designed in such a way that the recovered heat is returned to the energy cycle. During cooling of the wort, the so-called cold trub precipitates out which consists mainly of undesirable hops bittering compounds and low molecular weight proteins which have combined with tannins from the raw materials.
The fermentation of our prospective wheat beer is carried out in open fermenting vats. The cooled wort (pitching wort) is placed into individual fermenting vats where it is pitched with top-fermented yeast cultivated in our in-house yeast cultivator. This guarantees consistent quality. Maintaining the health of the yeast is a prime necessity for the master brewer. That's why he takes such care to maintain ideal conditions in the fermenting cellar.
Picture: Open fermenting vat (Schneider Weisse).
This is also where the so-called main fermentation takes place. Precise temperature control is of the essence here. Top-fermented beers are mostly kept at a warmer temperature than bottom-fermented ones. This reduces the time required for main fermentation accordingly. It is in the fermenting cellar that the malt sugars obtained during wort production are fermented into alcohol and carbon dioxide by the yeast. At the end of main fermentation the top-fermented yeast rises to the top and is skimmed off. The ratio of initial yeast to the yeast yield is about 1:4. The original pitching wort has now become "young beer".
When it is bottled, the young wheat beer contains only very little carbon dioxide.
