Dive into the fascinating world of brewing with Brettanomyces, the wild yeast that creates complex, funky beers with distinctive character. This comprehensive guide covers everything from selecting the right Brett strains for your desired flavor profile to managing fermentation, aging, and packaging your wild ales. Learn proven techniques for harnessing Brett’s unique capabilities, troubleshooting common issues, and creating beers with incredible depth and complexity that conventional brewing approaches simply cannot achieve.
Welcome to the wild side of brewing. That tantalizingly complex funk, that barnyard aroma, those tropical fruit notes that somehow emerge from what traditional brewing textbooks once classified as “spoilage” organisms – these are the hallmarks of brewing with Brettanomyces. Once considered only a contaminant to be avoided at all costs, this fascinating yeast genus has become the darling of craft brewers seeking to create complex, distinctive beers that push beyond conventional flavor boundaries.
Whether you’re a professional brewer looking to add a Brett beer to your lineup or a curious homebrewer ready to venture beyond Saccharomyces, this in-depth guide will walk you through everything you need to know about brewing with Brettanomyces. From understanding the various strains and their characteristics to practical brewing techniques and troubleshooting, we’ll cover the full spectrum of Brett brewing.
Understanding Brettanomyces: Not Your Typical Yeast
Brettanomyces (often shortened to “Brett”) is a genus of yeast that behaves quite differently from the Saccharomyces cerevisiae that most brewers are familiar with. While both are fungi that can ferment sugar into alcohol, Brett has some unique characteristics that make working with it both challenging and rewarding.
The Taxonomy and Origins of Brett
Brett was first classified in 1904 by N. Hjelte Claussen at the Carlsberg brewery, where it was identified as the organism responsible for the distinctive secondary character of English stock ales. The name Brettanomyces comes from the Greek for “British fungus,” reflecting its discovery in British brewing traditions.
According to the American Society for Microbiology, there are five main species of Brettanomyces recognized today:
| Species | Common Flavor Profile | Typical Sources | Commercial Availability |
|---|---|---|---|
| B. bruxellensis | Horse blanket, barnyard, spicy | Lambic, wine, wood | Many strains available |
| B. anomalus | Tropical fruit, smoky, spicy | Wild ales, cider | Several strains available |
| B. claussenii | Fruity, pineapple, less funk | English old ales | Limited availability |
| B. custersianus | Fruity, solvent-like | Rare in brewing | Very limited |
| B. naardenensis | Medicinal, phenolic | Rare in brewing | Rarely available |
Of these, B. bruxellensis (often called B. brux) and B. anomalus are the most commonly used in brewing, with B. claussenii gaining popularity for its more approachable flavor profile.
How Brett Differs from Saccharomyces
Understanding the key differences between Brett and conventional brewing yeast is essential for successful fermentation:
- Metabolism: Brett can metabolize complex sugars that Saccharomyces cannot, including dextrins and cellulose.
- Oxygen Relationship: Unlike Saccharomyces, Brett can thrive in both aerobic and microaerobic conditions, with different metabolic pathways producing different flavors.
- Fermentation Timeline: Brett works much more slowly, often continuing to develop flavors over months or even years rather than days or weeks.
- Flavor Production: Brett produces a wider range of flavor compounds including phenols, esters, and fatty acids that create its characteristic profile.
- Cell Structure: Brett cells are smaller and more resilient than Saccharomyces, making them harder to filter and more likely to survive in challenging conditions.
Tyler Yeastman, microbiology expert, explains in his work with the Brewing Science Institute: “Brett’s unique enzymatic capabilities allow it to create flavor compounds that Saccharomyces simply cannot produce. This includes the ability to transform bound compounds in malt and hops into aromatic precursors, essentially ‘unlocking’ flavors that would otherwise remain imperceptible.”
The Flavor Spectrum of Brett Beer
Perhaps the most fascinating aspect of brewing with Brettanomyces is the incredible range of flavors this yeast can produce. Understanding this spectrum is key to designing recipes that highlight the characteristics you’re seeking.
The Brett Flavor Wheel
The flavor profile of Brett beers can be roughly categorized into several main groups:
- Barnyard/Funk: Often described as “horse blanket,” leather, musty, or earthy
- Fruity: Tropical fruits, stone fruits, or dried fruits
- Phenolic: Spicy, clove-like, smoky, or medicinal
- Acidic: Tart, tangy, or mildly sour notes (though Brett itself doesn’t produce significant acidity)
- Funky-Earthy: Wet hay, basement, or mushroom characteristics
According to research published in the Journal of the Institute of Brewing, the specific flavor compounds produced depend on numerous factors including:
- Brett species and strain
- Fermentation temperature
- Available nutrients
- Oxygen exposure
- Substrate (the sugars and other compounds available)
- Co-fermenting organisms
- Age of the beer
Strain Selection for Targeted Flavor Profiles
Choosing the right Brett strain is perhaps the most important decision in designing your funky beer. At Brew My Beer, we’ve conducted extensive experiments with different commercial strains, documenting their flavor impacts across various beer styles.
Common commercial strains and their typical flavor profiles:
| Commercial Name | Species | Dominant Flavor Notes | Funk Level | Best Uses |
|---|---|---|---|---|
| WLP650 (White Labs) | B. bruxellensis | Classic barnyard, leather, spicy | High | Belgian styles, secondary fermentation |
| WLP653 (White Labs) | B. lambicus | Intense cherry pie, pie crust, funky | Very High | Lambic-inspired beers, long aging |
| WY5112 (Wyeast) | B. bruxellensis | Tropical fruit, pineapple, moderate funk | Medium | American wild ales, primary fermentation |
| WY5526 (Wyeast) | B. lambicus | Cherry, pie crust, earthy | High | Belgian styles, blending |
| Omega OYL-210 | B. bruxellensis | Tropical, pineapple, mild funk | Low-Medium | Approachable funky beers, IPAs |
| Escarpment Fruit Bomb | B. bruxellensis | Intense tropical fruit, low funk | Low | NEIPAs, fruit beers |
| The Yeast Bay Amalgamation | Brett blend | Complex, evolving character | Medium-High | Complex wild ales, long aging |
Brewing Techniques for Brett Beer
Now that we understand what Brett is and what flavors it can create, let’s explore how to actually brew with it.
Equipment Considerations
Before you start brewing with Brett, consider these equipment factors:
- Dedicated Equipment: Many brewers maintain separate equipment for Brett beers to avoid cross-contamination.
- Fermentation Vessels: Glass, stainless steel, or wood are all suitable, though wood will impart additional character and harbor Brett for future fermentations.
- Airlocks: Brett fermentations can be slow and may require extended aging, so use airlocks that can be maintained for months.
- Bottling Equipment: Brett can continue fermenting for months, so having dedicated bottling equipment is advisable.
Mark Kegman, brewing equipment specialist, notes that “while having separate equipment is the safest approach, thorough cleaning and sanitization can make shared equipment viable if dedicated tools aren’t possible. Just be extremely diligent about sanitization.”
Recipe Design for Brett Beers
Designing a great Brett beer requires thinking differently about recipe formulation:
Malt Selection
- Dextrins: Including malts that contribute dextrins (like caramalts) gives Brett more to work with over time.
- Base Malts: Pilsner malt provides an excellent canvas for Brett character to shine.
- Specialty Malts: Use restraint with strongly flavored specialty malts, as they can compete with Brett character.
Hop Selection
- Alpha Acids: Brett can transform hop compounds, sometimes reducing perceived bitterness over time.
- Varieties: Earthy, spicy hops like Saaz complement Brett funk, while tropical varieties can enhance Brett’s fruity aspects.
- Timing: Consider that hop character will evolve significantly during Brett fermentation.
Water Chemistry
- Mineral Profile: Moderate mineral content generally works well, similar to Belgian ales.
- pH Considerations: Start with slightly higher mash pH (5.4-5.6) as Brett fermentation may reduce pH over time.
Primary vs. Secondary Use of Brett
There are three main approaches to incorporating Brett into your brewing process:
1. Brett-Only Primary Fermentation
Using Brett as the only fermenting organism from the beginning:
- Timeline: Typically 1-3 months minimum
- Attenuation: Very high (often 90%+)
- Flavor Profile: More restrained funk, higher fruit character
- Challenges: Longer lag time, requires patience
2. Mixed Primary Fermentation
Using Brett alongside Saccharomyces and/or bacteria from the start:
- Timeline: 1-2 months initially, develops over 6+ months
- Attenuation: Very high (85-95%)
- Flavor Profile: Complex, evolving character
- Challenges: Unpredictable, requires blending skills
3. Secondary Brett Fermentation
Adding Brett after primary fermentation with Saccharomyces is complete:
- Timeline: 3-12+ months for full development
- Attenuation: Further 5-15% beyond Saccharomyces
- Flavor Profile: More pronounced funk, classic “Brett character”
- Challenges: Very long aging requirement
According to the American Homebrewers Association, many brewers find that secondary Brett additions produce more complex, funky profiles, while primary Brett fermentation often yields more tropical fruit character with less intense funk.
Fermentation Management
Managing Brett fermentation requires different approaches than conventional brewing:
Temperature Considerations
Brett generally produces more fruit character at lower temperatures (65-70°F/18-21°C) and more funk at higher temperatures (75-85°F/24-29°C). However, extremely slow fermentations may result from temperatures below 65°F.
Oxygen Management
Unlike Saccharomyces, Brett’s relationship with oxygen is complex:
- Initial oxygenation: Similar to conventional brewing
- Microoxygen exposure during aging: Can enhance Brett character development but may increase acidity
- Headspace during aging: Some headspace often benefits Brett development
Nutrient Requirements
Brett has different nutritional needs than Saccharomyces:
- Nitrogen requirements: Generally lower
- Micronutrients: Benefits from zinc and other trace minerals
- Complex nutrients: Often struggles with simplified nutrient additions
Dr. Linda Bisson of the UC Davis Department of Viticulture and Enology has found that Brett can utilize nitrogen sources that Saccharomyces cannot, allowing it to continue working in nutrient-poor environments that would stall conventional yeast.
Aging, Packaging, and Serving Brett Beers
The journey of a Brett beer doesn’t end with fermentation—proper aging, packaging, and serving are crucial to success.
Aging Considerations
Brett beers generally require significant aging:
- Minimum Aging: 1-3 months for primary Brett beers, 6+ months for secondary additions
- Optimal Aging: Many Brett beers continue improving for 1-3 years
- Aging Vessels: Glass carboys, stainless steel, or wood (which will add its own character)
- Sampling Protocol: Regular tasting is essential to track development
Packaging Challenges
Packaging Brett beers presents unique challenges:
Bottling Considerations
- Carbonation: Brett can continue fermenting for months or years, potentially leading to overcarbonation
- Options to Control Carbonation:
- Ensure complete fermentation (very difficult to guarantee with Brett)
- Pasteurize (affects flavor significantly)
- Sterile filter (difficult with Brett’s small cell size)
- Calculate residual sugar precisely and package accordingly
Kegging Considerations
- Advantages: Easier to manage carbonation levels, can refrigerate to slow Brett activity
- Disadvantages: Takes up keg space for extended periods, cross-contamination risks
- Best Practices: Dedicate kegs to Brett beers, use separate serving lines
Serving Temperature and Glassware
To fully appreciate Brett beers:
- Serving Temperature: 45-55°F (7-13°C) highlights complexity better than colder temperatures
- Glassware: Tulip, wine glasses, or wide-bowled Belgian glasses showcase aromatic complexity
- Pouring Technique: Some Brett beers benefit from decanting, others from rousing yeast
Troubleshooting Brett Fermentations
Even experienced brewers encounter problems with Brett beers. Here are some common issues and solutions:
Stalled Fermentation
Potential Causes:
- Insufficient oxygen during initial stages
- Lack of accessible nutrients
- Temperature too low
Solutions:
- Rouse yeast gently
- Raise temperature 5-10°F
- Consider adding oxygen, but be cautious of oxidation flavors
- Be patient—what seems “stalled” may just be Brett’s naturally slow pace
Excessive Funk/Unpleasant Flavors
Potential Causes:
- High fermentation temperature
- Excessive oxygen exposure
- Contaminating organisms
- Particular Brett strain characteristics
Solutions:
- Blend with clean beer
- Extended aging may help flavors integrate
- Temperature control in future batches
- Strain selection adjustments
Overcarbonation
Potential Causes:
- Packaging before Brett has completed fermentation
- Unexpected resumption of Brett activity
Solutions:
- Refrigerate bottles to slow activity
- Carefully release pressure periodically
- For future batches, ensure complete fermentation or calculate residual sugar precisely
Creating Your Brett Beer Recipe
Ready to create your own Brett beer? Here are some proven recipes to inspire you:
Brett Saison Recipe (5 gallons/19L)
Ingredients:
- 8 lbs (3.6 kg) Pilsner malt
- 1 lb (0.45 kg) Wheat malt
- 0.5 lb (0.23 kg) Munich malt
- 1 oz (28g) Styrian Goldings (5.5% AA) at 60 min
- 1 oz (28g) Saaz (3.5% AA) at 10 min
- Saccharomyces Saison strain (primary)
- Brett bruxellensis (secondary)
Process:
- Mash at 149°F (65°C) for 60 minutes
- Boil 90 minutes
- Ferment with Saison yeast at 75-80°F (24-27°C) for 2 weeks
- Add Brett, age 3-6 months at 70-75°F (21-24°C)
All-Brett IPA Recipe (5 gallons/19L)
Ingredients:
- 10 lbs (4.5 kg) Pale ale malt
- 1 lb (0.45 kg) Carapils malt
- 1 oz (28g) Warrior (15% AA) at 60 min
- 1 oz (28g) Citra at 10 min
- 2 oz (56g) Citra at flameout
- 2 oz (56g) dry hop for 5 days
- Brett Trois or fruit-forward Brett strain
Process:
- Mash at 152°F (67°C) for 60 minutes
- Pitch ample Brett starter
- Ferment at 68°F (20°C) for 4-6 weeks
- Add dry hops for final 5 days
- Package when gravity is stable (typically below 1.005)
The Future of Brett Brewing
The world of Brett brewing continues to evolve rapidly. Recent trends and developments include:
- New Brett Strains: Labs are isolating and characterizing wild Brett strains with novel flavor profiles.
- Mixed Cultures: Brewers are creating house cultures combining multiple Brett strains with Saccharomyces and bacteria.
- Brett IPAs: The fruity characteristics of certain Brett strains pair wonderfully with hop aromatics, creating a growing category.
- Controlled Oxygen Exposure: More precise methods for controlled microoxidation are helping brewers develop Brett character more predictably.
According to Miguel Cerveza, international beer styles expert, “We’re just scratching the surface of what’s possible with Brett. As our understanding of this yeast improves, we’ll see even more innovative approaches to harnessing its unique capabilities.”
Embracing the Funk
Brewing with Brettanomyces represents one of the most exciting frontiers in craft brewing. While it requires patience, attention to detail, and a willingness to embrace unpredictability, the complex, unique beers that result are well worth the effort. From subtle tropical fruit notes to bold barnyard funk, Brett offers flavor possibilities that simply cannot be achieved with conventional brewing approaches.
Whether you’re making your first Brett beer or your fiftieth, remember that this journey is about exploration and discovery. Each batch will teach you something new about this fascinating organism and how it interacts with different ingredients and processes. Take good notes, be patient, and don’t be afraid to experiment—the world of Brett brewing rewards the curious and the bold.
About the Author:
Tyler Yeastman is a microbiologist who left his lab job to explore the fascinating world of wild fermentation. He maintains a library of over 100 isolated wild yeast strains and bacterial cultures collected from around the world. Tyler specializes in lambic-style beers, spontaneous fermentation, and mixed-culture brewing that produces complex, terroir-driven flavors. His home lab includes custom equipment for yeast propagation and analysis. Tyler frequently collaborates with local breweries to develop signature house cultures based on microorganisms native to their environments.
