I think I caught wild yeast, now what?
 

I recently found a patch of raspberries growing in my backyard and decided to pick some to try and wrangle some yeast. I was making a starter for another batch of beer so I poured about 2oz into a sanitized glass measuring cup and tossed the raspberries in. It's been about 4 days now and I saw some small bubbles on top and the gravity looks like it's dropped a little. I also tasted a little and it had a pretty good sour taste to it (like a raspberry lambic). I'm wondering what my next step is? should I let it ride a while to kill off any bugs like ecoli. Should I start stepping it up right away and get ready to brew with it? Should I plate it out and try to clean it up a bit by selecting colonies?

I'm planning a parti-gyle brew soon and thought this yeast might be a fun experiment for about a gallon of 3rd runnings.

What do you mean it looks like the gravity has dropped? Did you test it?

yes. The reason i phrased it that way is i'm using a refractometer and i'm new to using it. the OG of the starter was about 1.035, but then i threw raspberries in so i'm sure that added sugar. the reading i'm getting now after doing the correction(based on 1.035 og) is about 1.020. So i'm pretty sure it fermented but with that small change, me being new with the refractometer and maybe not doing the correction properly there's some doubt.

I poured a half gallon of wort off a batch of pale ale and mixed it with my wild yeast concoction. I have a small krausen and airlock activity. I'll give it a few weeks before I try it.

So how did it turn out??
 

I have some raspberries I'm thinking of playing with and I'm very curious to know how they worked out for you!

Did a similar thing with a variety of wild apples here last year. Fermented up a pretty tasty little test batch of cider using just the wild yeast. I did not go so far as to isolate the strain -- just wanted to see if it was viable for making cider.

i collected some wild yeast off some raspberries i got at a roadside produce stand. fermented well just had a lot of really off flavors not very desireable. i would see what kind of flavor profile you get. if it turns out well, ramp it up

I currently have a bottle of beer that used the wild yeast in my fridge. I pulled a half gallon of wort off another batch and fermented with the wild fellas. at bottling i streaked a plate and isolated a few colonies and transferred those to 2 slants. I'll try the bottled beer and I also plan on making a very boring smash beer (mostly pilsner malt and whatever hop i have a lot of) so i can really test the flavor of the yeast.

ok so i'm drinking it now. I can't pick up any noticeable flavor from the yeast. only the fact that it didn't attenuate very well. There's a light fruitiness to it but i have a feeling that's from the raspberries.

just an update. I stepped up a 1L starter of this a few weeks ago and made a 3 gallon batch of american wheat. It was 50/50 wheat and pilsner malt and only cascade hops. It was in the neighborhood of 1.050 and 25 ibus. I tried to keep this pretty bland so any yeast flavor or aroma could come right through. I don't taste much in the way of yeast flavor but it definately has a funky brett smell to it. Probly gonna keg it this weekend and bottle a few just to see if any wild flavors come through with age.

EDIT: forgot to mention in between the 1 gallon test beer and the wheat i just made the yeast was plated and I slanted some of the healthier colonies. The starter i used for the wheat came from one of the slants