Bier & Gezondheid
http://www.bierengezondheid.be/index.php/articles/en/cid=17/aid=3020/


QUESTION & ANSWER

26/11/2008
TOP-FERMENTED AND BOTTOM-FERMENTED BEERS

Question: What is top-fermented beer? And what is bottom-fermented beer?

Valerie

Answer: The term top-fermented beer and bottom-fermented beer has to do with the type of yeast used in the brewing process. Bottom-fermented beers (Saccharomyces cervesiae) require fermentation running at a temperature of between 5 °C and 10 °C, the yeast cells produced sinking to the bottom of the tank. However, top-fermented beers (Saccharomyces carlsbergensis) are produced at 15 °C to 20 °C, the yeast cells rising to the top. Wheat beers (witbier or Weizenbier), trappist beers and manor house beers (kasteelbieren) belong to the category of top-fermented beers, while pilsner, lager-type beers and bock beers are bottom-fermented beers.