A bit of googling didn’t turn up any hits on this . . . but has anyone tried using cheap beer + DME as medium to capture wild yeast?
The Mad Fermentationist & Bootleg Biology methods both use lightly hopped, low gravity wort. But cheap beer would already be hopped & would test for alcohol tolerance at the same time, right?
To my opinion it is not the same. Beer has low pH and no additional nutrients.
Lightly hopped wort will be a better option as hops are bacteria and mold growth retardants.
if you are going to collect your own yeast do it at the time where there is a low bacterial and mold count like in early spring or late fall.
I think that you’d want to provide the best starting environment for yeast to grow from a few cells into a population with no alcohol at the very start. They will make alcohol soon enough. Intolerant yeasts will be out-competed.
Maybe I’m way off base, but wouldn’t capturing wild yeast be like making a starter? If so, how is beer going to ferment if it’s already fermented?
Yeah, me too. Yeast wants to eat sugar. What’s left in cheap beer is less bait to attract yeast than mold.
But he said cheap beer + DME. This is not really my area because I’m usually trying to AVOID wild yeast but reading the OP, I saw cheap beer + DME so … there’s your sugar and your mild hops.
What about picking wild fruit that already has wild indigenous yeast on its skin? Or maybe you’re trying to catch yeast that is in your house/brew room??? Then I would think that yeast would be a culmination of indigenous and latent commercial that you previously use.
This ^^^^
The DME provides the nutrients to grow.
I was thinking of the beer as a way to screen out yeasts (and other microbes) that aren’t hop-, pH-, & alcohol-tolerant. Basically moving some of the screening that happens later (when you start doing test brews) to earlier in the whole process.
My overall approach is Bootleg’s Method #2.
This isn’t unlike how I step up my dregs when growing cultures from a bottle-conditioned beer. I keep about an ounce of the beer along with the yeast dregs and add an equal amount of 1.040ish wort to it. The end result is a 1.020ish starter with half the ABV of the original beer, plus a reduced pH. For hopped beers, you get half the IBU’s as well. That helps protect the culture so unwanted microbial growth is suppressed.
My only concern with airborne innoculation is that the innoculation rate is so low, that the ABV and IBU may slow the growth of your desired innoculants, too. If I were doing it, I’d consider just lowering the pH to 4.5 with some lactic acid and rolling the dice with no alcohol or hops. This would make an interesting side-by-side if you’re going to go through the effort, though. You could add a few hop pellets to one starter and boil for 10 minutes or so. Another could have a small amount of vodka or Everclear added to hit 3% ABVish. Then a control, and possibly a pH-adjusted batch.
I’ve read that some lambic producers pre-acidify their wort to suppress enterobacter. So this would be similar to that but with pre-alcoholizing, too.
But I guess an experiment wd be in order to see if it’s genius or stupid.
Because the EU made them. Enterobacter drop out pretty quickly once you get a little alcohol.
I’m not sure if there is a benefit to your proposed process, but it wouldn’t hurt anything aside from spending a little extra money versus just using a small amount of hops and a little more DME.
You gotta do the experiment and see.