I am currently taking classes at Central Washington University for the craft beer trade. I am fascinated by wild yeast micro regions (ie: Lambic is only found with a 20km radius around Brussels).
So I want to do some experiments like placing open fermentation vessels in various locations around the Yakima Valley: Apple orchards, hop fields, cherry orchards and the like. I hope to find wild yeast that will yield unique and good tasting beer.
My questions for any who may know:
Do wild yeasts have seasons of peak activity? I’m guessing Summer to early Fall.
Do airborne bacteria have peak seasons?
Are there techniques to avoid bacterial infection while capturing wild yeasts?
I also wonder about the technique of setting over-ripe fruit out in order to capture wild yeast, then putting them in a starter to cultivate.
Anything else I’ve missed or should know? Any reference materials I should consult?
From what I have gathered in my research you want cool nights. this will increase the chances of getting yeast and reduce the chances of getting bacteria, or as much bacteria.
you are unlikely to capture ONLY yeast but bacteria can be good to (see lambic).
it seems like pre-acidifying your medium can help discourage bacteria from taking hold.
hopping your medium might help as well as yeast are more able to deal with the ant0microbial characteristics of hop oils.
you can take samples of fruit skin and place them directly in media as pretty much all fruit already has lots of yeast on it. These yeasts aren’t always great with malt sugars but you are experimenting after all.
I have a mason jar on the counter at home with some disgusting greyish brown krausen on top that came from my buddies last brew. He left the kettle out with a couple inches of wort and hop gunk sitting in the bottom for a couple days. when he went to clean it I asked him to save me a few hundred ml in a mason jar just to see what would happen. The yeast in my neck of the woods are known for producing unpleasant nail polish remover notes and that is more or less what I am getting.
I tried that with Upstate NY forest wild yeast and isolated 2 yeasts and 1 bacterial strain which I haven’t tested yet.
What was said above is true, but try it and see what you get. If something good happens, feel free to mail me a sample and I’ll isolate individual strains out
this last summer i had a fig from my tree that was sour, funky and good. next year i will try to isolate another like it and see what i can brew with it. i think the two previous posts sum it up pretty well according to my google research.
