This blend of lactic acid producing Lachancea thermotolerans isolates is unique from any yeast we’ve ever isolated, and represents the second time we’ve hit bioprospecting pay dirt with AltBrau. In addition to creating an acidic character that is much more complex, multi-dimensional and reminiscent of a traditional long-aged sour as compared to a kettle sour, here are some interesting facts about Berkeley Hills Sour Yeast Blend:
Optimally ferments and produces consistent acidity across a temperature range of 64-70 ºF
Attenuation and ester profile tuneable based on percent of fermentables as glucose:
62% (all malt base) - red apple
72 % (malt base + 10% glucose) - red apple/stone fruit
75% (malt base + 20% glucose) - stone fruit
Final pH tuneable based on percent of fermentables as glucose:
3.45-3.50 (all malt base)
3.30-3.35 (malt base + 10% glucose)
3.25-3.30 (malt base + 20% glucose)
Final pH is 0.1-0.2 units higher for any wort composition in open fermentation as compared to closed tank fermentation, while the attenuation remains unchanged
Produces similar results in the same wort composition across a range of pitch rates (1.0-2.5 million cells/mL/ºP)
Can be serially re-pitched and reused with consistent results
Metschnikowia reukaufii is a nectar specialist that was isolated from flowers in the Berkeley Hills of California, collected on a bioprospecting hike with Tim Decker of AltBrau. Evolutionarily, this yeast evolved to produce a more odorous and attractive nectar for pollinators by enzymatically altering otherwise inodorous nectar compounds including glycosides.
While only attenuating to 20-25% in brewer’s wort and not utilizing maltose or maltose derivatives, in malt-based co-fermentations it has been shown to drop gravity and pH of the fermentation faster, accentuate and modulate the flavor and aroma profile and soften the perceived bitterness of the finished product.
