Brettanomyces (often abbreviated Brett) is a genus of wild non-Saccharomyces yeast, which:

• Ferments residual sugars that are non-fermentable by conventional yeasts

• Produces specific aromatic compounds:

  • 4‑EG (4-ethylguaiacol) → smoky, clove, leather notes

  • 4‑EP (4-ethylphenol) → medicinal, brett, wood, spice notes

  • Organic acids → adding light acidity

• Used alone or in co-fermentation with Saccharomyces, it makes it possible to:

  • Create wild, complex and aged beers

  • Develop aromatic profiles that evolve over time

Brettanomyces is therefore the “funky” yeast par excellence, bringing complexity and unique character to craft beers, particularly those aged in barrels.