Lallemand Sourvisiae Brewing Yeast

Sourvisiae® Sour Beer Yeast — Lallemand

Sourvisiae® makes sour beer simple. This bioengineered ale yeast (Saccharomyces cerevisiae) produces lactic acid during fermentation, letting you sour and ferment your beer in a single step — no mixed cultures, no separate souring vessel, no guesswork.

Pitch it like any conventional yeast and ferment as normal. Sourvisiae® delivers a clean, neutral base with a tangy, slightly fruity character — perfect for traditional Berliner Weisse, Gose, and modern fruited sours alike. Because it doesn't produce the off-flavors associated with Brettanomyces, Lachancea, or lactic acid bacteria, you get a consistent, reproducible sour every time.

Brewing Properties

• Fermentation temp: 15°C–22°C (59°F–72°F)
• Fermentation time: Vigorous fermentation complete in ~5 days
• Attenuation: Medium to High
• Flocculation: Medium to High
• Flavor/Aroma: Tangy, sour, slightly fruity
• Final beer pH: ~3.0
• Lactic acid: 8–15 g/L

A note on attenuation: Because sugar converted to lactic acid doesn't change wort density, final gravity readings will appear higher than expected — but residual sugar is actually lower than the number implies.

Microbiological Specifications

• Solids: 93–96%
• Living yeast cells: ≥ 5 × 10⁹ per gram
• Wild yeast: < 1 per 10⁶ yeast cells
• Bacteria: < 1 per 10⁶ yeast cells

Due to the highly acidic fermentation environment, re-pitching this yeast is not recommended.