Cultivate Yeast for a Characteristic

[Dannit]

Hello all, I've "captured" a wild yeast strain which I really like--produces the most amazing dessert aromas--but it doesn't like to go past about 9%ABV. If you were going to cultivate a strain for high attenuation, how would you go about selecting for that? I'm fairly new to the hobby, but I know about and have done yeast washing and storing multiple times now with this particular strain. But it would be nice to understand what protocol would allow me to gradually select for a higher-alcohol fermenter. I've used this wild strain to make red wine, but after it fermented up to between 5-9%alcohol, I added a commercial strain to finish it off to 13-14%. It would be really nice to be able to just use this wild strain all the way to dryness. (One thing I really like about it is that, even when stressed, it does not produce nasty rotten-egg aroma like the commercial yeasts I've used.)

 

[salcoco]

talk to a organic chemist.

 

[Americanhooch]

A shot in the dark here (I'm about as far from an organic chemist as it gets), but maybe do 3-5 one gallon batches at a time, culture a sample from the batch that produces the highest ABV, then repeat using that sample's culture. After a few generations you might get a difference.

 

[1d10t]

You probably have more than one strain using the techniques you describe. Yeast mutate and drift. I think pros streak plates to get individual colonies from a single yeast and then keep propagating from those plates. Even if you could get one to be more alcohol tolerant you may lose what you like about it along the way.

 

[Syrah-volution!]

talk to a organic chemist.

In real life, I actually am an organic chemist. My advice is to talk to a biologist!