Definition

Noun: A slow, cool-temperature alcoholic fermentation process during which yeast cells settle to the bottom of the fermenting vessel. This method is characteristic of brewing lager beers.

Usage

This term is used specifically in the context of brewing and microbiology to describe a fermentation technique. * The traditional method for making lager relies on bottom fermentation. * Bottom fermentation typically occurs at temperatures between 7°C and 13°C (45°F and 55°F).

Advanced Usage

• Technical Process: The term describes the behavior of yeast strains, which are less active at cooler temperatures and tend to flocculate (clump together) and settle after fermentation is complete.
• Contrast with Top Fermentation: It is often discussed in contrast to "top fermentation," which uses different yeast strains at warmer temperatures, resulting in yeast that rises to the top, and is used for ales.

Variants and Related Words

• Bottom-fermenting (adjective): Describes yeast or the process itself.
  • Bottom-fermenting yeast is essential for lager production.
• Lager fermentation: A common synonym referring to the beer style produced.
• Fermentation: The broader biochemical process of converting sugars to alcohol and gases.

Synonyms

• Lager fermentation
• Cool fermentation

Antonyms

• Top fermentation
• Ale fermentation

Noun

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