Sour Beer Glossary

Sour Beer: beer which has an intentionally acidic, tart, sour, or funky taste

American Wild Ale: all encompassing term for beers brewed in America using yeast or bacteria in addition to brewer's yeast for fermentation. Such beers may be similar Lambic or Oud bruin, and are typically fermented using a strain of brettanomyces for part or all of the fermentation. 

Barrel Aged: the process of aging a beer in used wine or spirit barrels. If there are microbes left in the barrel it can lead to a sour beer.

Berliner Weiss: cloudy sour wheat beer made with a mixture of yeast and lactobacillus. Modern versions may contain fruit.

Blending: the mixing together of different batches of beer to create a final product

Brettanomyces (aka "brett"): a strain of yeast that commonly lives on fruit. It can also ferment beer, although it works more slowly than Saccharomyces. It is also far less predictable than Brewer's yeast and can often lead to funky and sour flavors

Cool Ship: large, open air container used to cool down wort (recently boiled, unfermented beer). The open nature allows the percolation of wild yeasts and bacteria

Farmhouse Ale: a loose style mostly defined by local ingredients and a sense of terroir provided by native yeasts and microbes, often through the use of open fermentation

Flemish Red Ale: sour, reddish brown ale. Fermented with brewer's yeast and bacteria, then aged in wood and blended together to create the final product. Very few hops are used. It’s sometimes considered the most 'wine like' of all beers

Foudre (foo-der): large wooden vats, much larger than a barrel, used for fermenting and storing beer and wine. the porous nature of the wood allows for oxygen and microbes to affect the beer, often turning it sour.

Fruit Beer: often sour. Beers that have fruit added and are allowed to ferment with the wild yeast (usually brettanomyces) and sugar present in the fruit.

Gose (go-Suh): lactobacillus soured wheat beer with coriander and salt. Modern versions may contain fruit

Gueuze: a blend of 1, 2, & 3 year old lambics

House Culture: a custom mix of brewer's yeast, wild yeast, and bacteria that a brewery uses for their sour beers

Inoculate: The introduction of a microbe like yeast or microorganisms such as lactobacillus into surroundings capable of supporting its growth.

Kettle Sour: the process of using bacteria to sour a wort (unfermented beer) before it is fermented. Allows for the use of traditional brewer's yeasts and hops.

Killer Sour: a sour beer that kicks ass, takes names, and generally runs train through other, lesser, sours.

Lactobacillus (aka “lacto”): A bacteria, not a yeast. Converts sugars to lactic acid. This lowers the liquid’s pH, making it sour. It’s a relatively clean taste for drinkers, since lacto doesn’t produce much besides lactic acid

Lambic: a spontaneously fermented sour blonde ale, typically from the Zenne region of Belgium

Mixed Fermentation: the process of using brewer's yeast along with additional methods (bacteria, brettanomyces, open fermentation, etc...) to create a more complex beer

Open Fermentation: fermented in manner that allows the percolation of wild yeasts and bacteria. A cultured yeast is usually added to the mix as well

Oud Bruin or Flanders Brown Ale: reddish brown ale, soured through the use of yeast and bacteria, usually in stainless steel instead of wood as opposed to Flemish red ales which are aged in wood

Pediococcus (aka “pedio”): A bacteria, not a yeast. Produces lactic acid like lactobacillus. But many people find the resulting sourness harsher than that of lacto. It gives Brettanomyces more fuel to work with, so they’re often used together. It’s the bacteria that sours beers like lambics and Flemish reds.

Primary Fermentation: The first stage of fermentation carried out in open or closed containers, during which time the bulk of the fermentable sugars are converted to alcohol and carbon dioxide gas.

Saccharomyces or Brewer's Yeast: various strains of cultured yeast responsible for fermenting beer

Secondary Fermentation: a second, slower stage of fermentation in which the beer continues to develop.

Spontaneous Fermentation: fermentation that occurs without manually adding yeast. It only involves yeast and bacteria naturally occurring in nature. Often induced via cool ship or a barrel

Wort: unfermented beer