A relatively new (it wasn't really practical until refrigeration equipment became available in 1876) way of beer fermentation at low temperatures (typically 5-10 degress Celsius) where the yeast particles will sink to the bottom of the brewing vessel. The beer is 'lagered' (aged) for a period of 60 to 90 days.

All bottom-fermented beers are known as lagers, a term which in some countries (incorrectly) have come to mean a light, mild beer. Pils/Pilsner, Export, Bock, Doppelbock, Hell, and Maerzen are all bottom-fermented beers.

See also top-fermentation.