Sourvisiae® is a bioengineered ale yeast strain (Saccharomyces cerevisiae) capable of producing lactic acid during fermentation to provide brewers with an easy, reproducible, and mono-culture product for sour-style beer production.
Sourvisiae® is a revolutionary new yeast strain which allows brewers to ferment and sour their beers in one simple step; reducing cross-contamination risks, lowering costs, cutting total process time, and allowing brewers to obtain a consistent product. Sourvisiae® accomplishes this though a single genetic modification: a lactate dehydrogenase gene from a food microorganism which enables the yeast to produce high levels of lactic acid, the main compound that gives sour beers their flavor. The brewing process is conducted without any modifications; Sourvisiae® is pitched just like conventional yeast and ferments in a normal fermentation time. Sourvisiae® does not produce other flavor compounds associated with Brettanomyces, Lachancea, or Lactic Acid Bacteria, providing a cleaner and more reproducible souring process, with much shorter fermentation times.
Sourvisiae® is suitable for use in producing all styles of sour beer.
Brewing Characteristics - Primary Fermentation
In Lallemand’s Standard Conditions Wort at 20°C (68°F) Sourvisiae® yeast exhibits:
- Vigorous fermentation that can be completed in 5 days
- Medium to High Attenuation and Medium to High Flocculation
- Highly acidic and slightly fruity flavor and aroma
- The optimal temperature range for Sourvisiae® yeast when producing traditional styles is 15°C (59°F) to 22°C (72°F).
- Fermentation rate, fermentation time and degree of attenuation are dependent on inoculation density, yeast handling, fermentation temperature and nutritional quality of the wort.
- Because of the resulting low pH and highly acidic conditions, we do not recommend re-pitching this yeast.
Note: Attenuation may appear low due to the formation of lactic acid.
When sugar is consumed to produce lactic acid there is no change in the density/specific gravity of the wort, because lactic acid has a higher density than ethanol (roughly equivalent to the sugar that was consumed). Therefore, the amount of residual sugar in the finished beer is lower than the final density would imply. Production of lactic acid does not result in a loss of CO2.
Flavor & Aroma
This yeast produces a very acidic beer, with final beer pHs in the range of 3.0 and lactic acid in the range of 8 – 15g/L. The resulting flavor and aroma profile of the beer is a slightly fruity acidic beer.