Wild Yeast Question

[GarylandTerps]

First time posting here after lurking for a while. Excited to join the community for real!

I just tried harvesting wild yeast from my backyard and I think it may have worked. After about 3 days the pellicle (below) formed.



Now after a few more days it looks like a layer of yeast (?) formed on the bottom of the jar (pictured below). It's been at room temperature for a about a week. I started with around 6oz of 1.040 wort in the jar.



So my questions are:

• Does this appear to actually be wild yeast?
• Is the layer at the bottom yeast?
• From here what is the next move? Do I let it go a while longer? Do I decant the top and save the "slurry" in a smaller jar for when I'm ready to make a starter?

Thanks in advance!

 

[mashpaddled]

It looks like yeast but who really knows what you caught there. Pitch the whole thing into a larger starter and let it ferment out. See what it smells and tastes like. If it smells and tastes ok then try brewing with it.

 

[RPh_Guy]

Hey, welcome to HBT!

Does this appear to actually be wild yeast?

Check the s.g. with a hydrometer. If the density dropped significantly, then you got some alcohol-producing yeast.

I've done a bunch of wild captures from different sources. In my experience most wild cultures only attenuate about 50-55%.

Is the layer at the bottom yeast?

Could be, or just trub. See above to confirm.

From here what is the next move? Do I let it go a while longer? Do I decant the top and save the "slurry" in a smaller jar for when I'm ready to make a starter?

There are a few things to consider with an unknown mixed culture...

Does your culture reach an attenuation you consider adequate?
Does it produce flavors that are enjoyable?
Do you want it to be sour?

The progression of microbes may change over time...
Will it continue to attenuate slowly?
How hop-tolerant are the bacteria? Will it sour slowly over time even with hops?
Will it get more funky over time? Do you want it to get funky? Are you expecting Brett flavors?

Will you be bottling or kegging?
If bottling, and unless you plan to isolate to dominant strain, I recommend you let it sit for several weeks at least, or maybe a couple months to make sure the gravity is stable.

You're going to want to keep it closed to avoid mold growth. There's no reason to decant the liquid.

I'm conservative because I have trouble finding the time to brew, so I would want to know how the culture will performs before adding it to a batch, but you're welcome to do whatever works for you.

Cheers

 

[GarylandTerps]

Bumping this old thread. So I left the mason jars alone for about 5 months until this week....and things have happened lol. Attached are the pictures of both jars. Both of them do not smell awful, actually kind of pleasant honey/citrus. The floating "things" have me a bit worried. Anyone seen anything like this before? I'm thinking of decanting and throwing them each into a starter. I did a gravity reading and one has dropped from 1.040 to 1.030, the other 1.040 to 1.023.

Just looking for any advice before I make a move!

 

[RPh_Guy]

The yeast are probably in pretty bad shape, or maybe even dead after sitting for 5 months.

Interesting pellicle photos, thanks for sharing!
I don't see anything that looks like mold. It wasn't fuzzy or hairy at any point, to your knowledge?

 

[brownni5]

Not great attenuation either. Likely not a great brewing yeast.

 

[RPh_Guy]

Not great attenuation either. Likely not a great brewing yeast.

I wonder whether a low attenuation yeast could actually make a good beer with the right recipe.

 

[GarylandTerps]

There was a third jar that did get hairy so I dumped that a while back. I don't remember these being moldy to my knowledge. Might just throw it in a starter to see what happens! Appreciate the feedback!

 

[Dhagey90]

That one picture from the top that has dark spots looks suspicious to me.