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Sourvisiae Lactic-Producing Yeast (500g)



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® contains 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. Sourvisiae® allows the brewer to ferment and sour the beer in one simple step, reducing cross-contamination risks, lowering costs, cutting total process time, and allowing brewers to obtain a consistent product. 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.


Attenuation 76-82%
Fermentation Range 15 - 22°C (59 - 72°F)
Flocculation High
Alcohol Tolerance 12% ABV
Pitch Rate 50-100 g/hL
Species Bioengineered (GMO) Saccharomyces cerevisiae


Microbiological Properties

Classified as Saccharomyces, a top fermenting yeast.
Typical Analysis of LalBrew Abbaye™ Yeast:

Percent Solids



5 x 10 CFU per gram of dry yeast

Wild Yeast < 1 per 10 yeast cells



< 1 per 10 yeast cells

Brewing Properties

In Lallemand’s Standard Sonditions Wort at 20°C (68°F), Sourvisiae® yeast exhibits:

  • Vigorous fermentation that can be completed in 4-7 days.
  • Medium to High Attenuation and High Flocculation.
  • High levels of lactic acid (no acetic acid) with slightly fruity
    flavor and aroma.
  • This strain is POF negative.
  • Final pH of 3.0-3.2 and lactic acid concentrations of 8-15g/L.
  • The optimal temperature range for Sourvisiae® yeast when
    producing traditional styles is 15 - 22°C (59 - 72°F).

Attenuation may appear lower due to the formation of lactic acid. Production of lactic acid does not result in a loss of CO2. When sugar is consumed to produce lactic acid, there is no change in density. Therefore, the amount of residual sugar in the finished beer is lower than the final density would imply. Lag phase, total fermentation time, attenuation and flavor are dependent on pitch rate, yeast handling, fermentation temperature and nutritional quality of the wort.