Kellerbier (cellar beer)

Kellerbier is an unfiltered, naturally cloudy beer that matures in a cool lagering cellar after primary fermentation and receives little or no added carbon dioxide. It still contains yeast and fine protein particles, which make it look hazy and contribute to a full-bodied, often slightly yeasty taste.

The style is not strictly defined. There are pale and dark versions, mostly bottom-fermented, ranging from mild to distinctly bitter. The foam is often less abundant and the impression softer and rounder than in filtered beers. Because of the yeast content, shelf life is shorter, so cooling and prompt consumption are advisable. It is closely related to Zwickelbier, and the two terms are used almost interchangeably in some regions.