Brettanomyces (Brett)

🔍 Quick Summary

Brettanomyces is a wild yeast that can add earthy complexity or barnyard funk depending on who’s sipping and how much is in the glass.

🛠️ What It Is

Brettanomyces, often called “Brett,” is a genus of yeast that can grow in wine, especially in red wines aged in barrel. Unlike Saccharomyces (the yeast responsible for primary fermentation), Brett is usually considered a spoilage yeast, though in small amounts, some winemakers and drinkers see it as a feature, not a flaw.

Brett can enter the winery via grape skins, old barrels, or contaminated equipment. It thrives in low-nutrient, high-alcohol environments and is notoriously hard to eradicate once established. It’s more common in low-intervention or natural wines, where sulfur use is minimal and filtration is avoided.

Brett doesn’t ferment sugar the same way as typical yeast—it produces volatile phenols that have distinctive aromas, some charming, others polarizing.

👅 Flavor & Style

Color

  • Minimal direct effect on color

Aromas & Flavors

  • Common Descriptors:

    • Band-Aid

    • Barnyard

    • Horse blanket

    • Leather

    • Smoke

    • Clove or medicinal notes

  • In Small Amounts: Can add savory depth and complexity

  • In Excess: Overwhelms fruit and masks varietal character

Structure

  • Tannin & Acidity: Not directly altered, but perception may change

  • Mouthfeel: Sometimes adds a drying, astringent edge

Common examples:

  • Southern Rhône blends (like Châteauneuf-du-Pape) – known for a “gamey” edge

  • Old World Syrah from the Northern Rhône – smoky, leathery notes may come from Brett

  • Traditional Rioja – subtle Brett can enhance the savory signature

🎯 Why Winemakers Use It

While often seen as a flaw, some winemakers tolerate or even invite small Brett populations for added complexity—especially in age-worthy reds.

  • Flavor effects – Introduces earthy, spicy, or umami-like notes that can deepen a wine’s profile

  • Structural impacts – Can shift the wine’s aromatic center from fruit-forward to savory

  • Technique variation –

    • Low Sulfur: Less SO₂ = higher risk of Brett

    • Old Barrels: More porous, harder to sanitize, more Brett-prone

    • Sterile Filtration: Used to remove Brett before bottling (not always favored in natural winemaking)

Tradeoffs:

  • Perception is personal—some love it, others find it offensive

  • Hard to control once it takes hold; it can ruin entire batches

  • In large amounts, Brett mutes varietal character and freshness

Brett is the punk rocker of the cellar—unpredictable, unruly, and sometimes brilliant in the right band.

🔗 Related Topics to Explore

  • 🍷 Oak Aging – A common breeding ground for Brett

  • 🧪 Native Yeast Fermentation – Natural fermentations increase Brett risk

  • 🧂 Sulfites in Wine – The key control method for Brett management

  • 🍇 Syrah – A variety that often hosts Brett-like complexity

  • 🧼 Sanitation in Winemaking – The frontline defense against Brett

🤓 Deep Dive Topics

  • Brettanomyces – Wikipedia

  • Wine Faults – Wikipedia

  • Fermentation in Winemaking – Wikipedia

  • Sulfites in Wine – Wikipedia

  • Microbiology of Wine – Wikipedia