organism group
Mixed fermentation
Deliberate fermentation with several organisms — typically Saccharomyces plus Brettanomyces and lactic bacteria — usually over months in wood.
The full record
Mixed fermentation has its own catalogue entry with the detail this page summarises — mechanism, temperatures and what goes wrong.
Mixed fermentation — Ferment with a deliberately chosen combination of organisms — Saccharomyces with Brettanomyces, Lactobacillus and/or Pediococcus — over months or years.
The organisms work in succession rather than together: Saccharomyces consumes the simple sugars first, lactic bacteria then produce acidity, and Brettanomyces works through the remaining dextrins over a much longer period. The sequence is why these beers take a year or more.
Behaviour
| Apparent attenuation | 85–100% |
|---|
Used in
- Flanders red ale
A deep red sour ale matured for years in oak foeders, balancing sharp acidity against dark fruit and a vinous depth.
- Oud Bruin
An East Flanders aged brown ale, maltier and less sharply acidic than Flanders red, with raisin and caramel depth.
- American wild ale
A broad New World category of mixed-fermentation and barrel-aged sour beers, often fruited, with no fixed base style.