Brettanomyces and Saccharomyces Co-fermentation
Funky mixed fermentations, for the purposes of this article, refer to fermentations that contain Saccharomyces and Brettanomyces. They do not contain lactic acid bacteria such as Lactobacillus and Pediococcus. As such, these beers may have a lightly tart flavor, but are not described as being sour (see the Mixed Fermentation page). The flavor of funky beers is often dominated by the array of flavor compounds produced by Brettanomyces (see Brettanomyces metabolism). Generically speaking, these flavors range from tropical fruits, stone fruits, smoke, barnyard animal funk, bitterness that lingers on the palate longer than hop bitterness and is accompanied by undertones of fruit, horse blanket, sweat, body odor, etc.
Brewing Methods
Conceptual graph of dynamics of funk expression and inoculation timing of Brettanomyces. Y-axis for each microbe group depicts relative activity which combines in a conceptual sense: growth, attenuation and production of flavor compounds. Plot drawn by Drew Wham based on concepts discussed in American Sour Beer [1]
| Technique | More Funk | Less Funk | Note |
|---|---|---|---|
| Inoculation timing | After Saccharomyces has finished fermentation | At the start of Fermentation | See figure 1 |
| Brettanomyces Inoculation cell count | Lower cell count | Higher cell count | Significantly interacts with the timing of inoculation |
| Strain of Saccharomyces | Phenol positive strain | Phenol negative strain | Pof+ strains of S. cerevisiae form 4-vinylguaiacol by enzymatic decarboxylation of ferulic acid |
| Ferulic Acid | More Ferulic Acid | Less Ferulic Acid | A precursor of 4-vinylguaiacol |
| Time since Inoculation | Aged Beer | Young Beer |
References
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