bottom fermentation

from WordNet (r) 3.0 (2006)

bottom fermentation
    n 1: 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

from The Collaborative International Dictionary of English v.0.48

Bottom fermentation \Bot"tom fer`men*ta"tion\
   A slow alcoholic fermentation during which the yeast cells
   collect at the bottom of the fermenting liquid. It takes
   place at a temperature of 4[deg] - 10[deg] C. (39[deg] -
   50[deg]F.). It is used in making lager beer and wines of low
   alcohol content but fine bouquet.
   [Webster 1913 Suppl.]