species
Pediococcus
A hop-tolerant lactic bacterium central to lambic and Flemish sours, notorious for a slimy intermediate stage.
Unlike most Lactobacillus, Pediococcus tolerates hops, which is how it survives in lambic despite the high aged-hop rates. It produces lactic acid slowly and also large amounts of diacetyl.
It characteristically passes through a "sick" phase where it produces exopolysaccharides that make the beer viscous and rope-like. In a mixed fermentation, Brettanomyces subsequently consumes both the diacetyl and the polysaccharides — which is why time is not optional in these styles.
Behaviour
| Scientific name | Pediococcus damnosus |
|---|
Used in
- Lambic
Spontaneously fermented Belgian wheat beer, matured in oak for years — funky, acidic, dry and unlike any other beer.
- Gueuze
A blend of young and old lambic, refermented in bottle — intensely complex, bone dry and Champagne-like in its carbonation.
- American wild ale
A broad New World category of mixed-fermentation and barrel-aged sour beers, often fruited, with no fixed base style.
Evidence
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Pediococcus produces a viscous ropy phase in mixed fermentation that Brettanomyces subsequently breaks down, so ropiness in a maturing sour beer is a normal stage rather than a spoiled batch.
Backed by a source
Sources: Yeast: The Practical Guide to Beer Fermentation — print; Journal of the Institute of Brewing