Brettanomyces
The wild yeast of lambics, sours, and farmhouse beers. Slow, complex, and unforgiving once it's in your equipment.
What it tastes like
Brettanomyces (or 'Brett') is the wild yeast that defines lambic, gueuze, Flanders red, and most aged American sours. It works slowly — months or years rather than weeks — and produces deeply complex character: barnyard, leather, tropical fruit (mango, pineapple), funk, light tartness. It's also the most polarizing yeast in craft brewing: some brewers spend years building dedicated Brett-only equipment (separate hoses, fermenters, even rooms), because once Brett gets into your stainless and rubber, it doesn't leave.
Best in these styles
Fermentation profile
Brett is slow. Primary fermentation may not produce noticeable character — wait 3-12+ months for full development. Many brewers ferment primary with Saccharomyces (US-05 or saison strain) to do the initial sugar-eating, then pitch Brett as a secondary fermentation in a separate vessel. Over months, Brett breaks down complex sugars Saccharomyces leaves behind, dropping FG further and developing characteristic funky character.
Available as
Brettanomyces is sold under multiple supplier brand names — same or near-identical strain.
| Format | Supplier | Product code | Notes |
|---|---|---|---|
| Liquid | White Labs | WLP650 Brettanomyces Bruxellensis | 100B cells |
| Liquid | White Labs | WLP645 Brettanomyces Claussenii | 100B cells |
| Liquid | Wyeast | 5112 Brettanomyces Bruxellensis | 100B cells |
| Liquid | Wyeast | 5526 Brettanomyces Lambicus | 100B cells |
| Liquid | Omega | OYL-202 All The Bretts | Various Multi-strain Brett blend |
| Liquid | Imperial | Suburban Brett B15 | 200B cells |
Comparable strains
If you can't source this strain, these alternatives bring overlapping character or fermentation behavior.
History
The name 'Brettanomyces' means 'British fungus' — first isolated from English stock ales in 1904. For decades it was considered a beer-spoiling contaminant, until Belgian lambic brewers (and later American craft brewers) recognized that the slow funk development was a feature, not a flaw. Russian River, Allagash, Hill Farmstead, and Jester King helped establish American wild ales as a legitimate category in the 2000s-2010s.