bottom fermentation - a slow kind of alcoholic fermentation at a temperature low enough that the yeast cells can sink to the bottom of the fermenting liquid; used in the production of lager

chemical action, chemical change, chemical process - (chemistry) any process determined by the atomic and molecular composition and structure of the substances involved

top fermentation - a violent kind of alcoholic fermentation at a temperature high enough to carry the yeast cells to the top of the fermenting liquid; used in the production of ale; "top fermentation uses a yeast that ferments at higher temperatures than that used for bottom fermentation"

vinification - the process whereby fermentation changes grape juice into wine