Ok, I can buy that WLP051 is actually Mendocino/Hopland Yeast. But if that strain itself came from New Albion, what is WLP076? (https://www.whitelabs.com/yeast-bank/wlp076-old-sonoma-ale-yeast)
It is probably the culture as it appeared when Jack received it from U.C. Davis. Yeast strains mutate in use, resulting in different performance characteristics. For example, here are the characteristics of BRY-96 as cataloged by Siebel:
BRY: 96
Reception Date: 4/1/1967
Type: Ale
Melibiose: No
37°C Growth: Yes
Glucose: Yes
Maltose: Yes
Maltotriose: Yes
POF: No
High Att. %: 87%
Low Att. %: 84%
Fermentation progress: Slow
Significant flavors: Red/green apple, pineapple, alcoholic
Aromatic compounds: Ethyl acetate, Acetaldehyde, Ethyl propionate, Propanol
BRY-96 is definitely Chico's mother strain. That has been confirmed from the head brewer at Chico. However, Chico behaves differently than BRY-96. For example, I would not call its fermentation progress slow. That difference was caused by selective pressure. Every time we plate a culture for "singles" and select a colony to slant or grow, we are producing a new isolate that may have slightly different brewing characteristics due to mutations that occur over time when a culture is repitched. For example, did you know that there is a W-34/78 culture in addition to W-34/70? The difference is that W-34/78 is 78th isolate from culture W-34 whereas w-34/70 is the 70th isolate. There also now appears to be a sub-isolate of W-34/70 called W 34/70-6.94; however, I could be wrong on that one. Here we have the same culture producing cells with different brewing characteristics.
From Hefebank Weinhenstephan:
W34/70 (Saccharomyces pastorianus ssp. carlsbergensis)
It is not without reason that the W34/70 is one of the best-known beer yeasts. This yeast is excellently suited for the production of various bottom-fermented beer specialities up to a gravity of 16.5°P. It is characterized by
- a fine ester note
- low contents of higher alcohols and sulphur compounds
- very good fracture formation capacity
- very good diacetyl reduction
- normal to high AV° (approx. 78-81%)
Recommended fermentation temperature: 11-12°C (10-14°C)
W34/78 (Saccharomyces pastorianus ssp. carlsbergensis)The W34/78 is a very respected yeast strain among connoisseurs. This yeast is excellently suited for the production of various bottom-fermented beer specialities up to a gravity of 16.5°P. It is characterized by
- a fine ester note
- low content of higher alcohols
- somewhat weaker fracture formation capacity
- pleasant light sulphur note
- very good diacetyl reduction
- high AV° (approx. 80-83%)
Getting back to BRY-96 mutations, the significant esters of BRY-96 are red/green apple and pineapple. However, many brewers have noted a peach ester from US-05. Is that ester the result of mutations that occur when the strain is propagated in bioreactor under aerobic conditions? The ester that smells most like peach is linalyl butyrate, which is a condensation reaction between linalool and butyric (a.k.a. butanoic) acid. Linalool is a tertiary alcohol of myrcene and myrcene is an essential oil in hops. From what I understand, it is the most plentiful essential oil found in hops. If linalool is coming from the hops, then where is the butyric acid coming from? My guess is it is either from one heck of a mutation in what it is relatively neutral yeast strain or bacterial contamination. I never got peach from US-05 the few times I pitched it; therefore, I am led to believe that it is brewhouse or yeast batch specific, which, in turn, leads to bacterial contamination probably being the culprit.