GY7B: Philly Sour

GY7B is a species of Lachancea that was discovered by the University of the Sciences in Philadelphia and cultured by Lallemand under the name WildBrew Philly Sour.

The unique characteristic of Philly Sour is that it produces both lactic acid and ethanol during its fermentation, meaning it can be used to produce sour beers without introducing bacteria.

It generates lactic acid during the first 3-5 days of fermentation with final attenuation and ethanol production completed by 7-14 days.

Souring potential depends on pitch rate and glucose concentration of the wort. GY7B can sour a beer to a pH of 3.2 – 3.6 with 3 – 8 g/L of lactic acid.

Aroma Profile

Sour with notes of red apple and stone fruit, notable peach, and honeydew melon.

Red Apple2/5
Tropical Fruit3/5
Citrus Fruit2/5
Green Apple1/5
Source: Lallemand Brewing


Apparent AttenuationHigh, 80-85%
Head retentionGood
Temperature Range20°C(68°F) – 25°C(77°F)
Alcohol ToleranceMedium-high, up to 9% ABV
Pitch Rate50 – 100g/hL to achieve a minimum of 0.5 – 1 million viable cells/mL
Source: Lallemand Brewing and WBC Connect 2020 talk

Suitable Styles

Philly Sour is suitable, according to Lallemand, for brewing Berliner Weiss, Gose, Sour IPA and American Wild Ales.
While not style-accurate Philly Sour can also be used to brew lambic-like ales.

More information

Lallemand: WildBrew Philly Sour

The Brü Lab Episode 003 | Lactic Acid Producing Yeast w/ Dr. Matt Farber

33 – GY7B: a novel yeast species capable of bacteria-free sour beer production