Capturing wild yeast -- and apparently mold

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I've been following this thread for some time:
https://www.homebrewtalk.com/f127/howto-capture-wild-yeast-101886/
Lots of good info in there, and it inspired me to capture my own backyard yeast strain. I boiled up some water and light DME to a gravity of ~1.030, poured it into a mason jar, covered it up with some cheesecloth, and left it outside for a couple of days to take in the atmospheric goodness. Then I brought it inside and put some sanitized foil over the top. I'm basically treating it like a 1 quart starter at this point, sans stir plate.

It's a week later, and I have a nice, cloudy wort with a good 1/2" of kräusen on top. This is a good thing! Unfortunately, I also appear to have a few little fuzzy mold patches growing along the sides, right above the kräusen. I would assume this is a bad thing. The smell is a combination of sour and sweet, and the mold ranges from snow white to kind of a pinkish color.

My inclination is to push on, let the thing ferment out, and then try to be extra careful when pouring into the next starter wort to step it up. My (admittedly poor) understanding is that mold requires oxygen to grow, so I'm hoping that the CO2 and alcohol will ultimately kill the mold.

Any thoughts? Bad idea? Worth a go?
 
Scoop out the mold using a sanitized spoon. The yeast will do a good job stopping new clumps from forming, but the visible clumps will be resilient unless you physically remove them, since they already have pretty large populations.
 
Thanks for the comments and suggestions. The starter wort has more or less fermented out at this point and is beginning to clear. There's a good layer of yeast on the bottom (or what I presume to be yeast). What I think I'll do is wait a couple more days and then physically remove the mold from above the level of the liquid. Then decant off most of the liquid and pour the dregs into a fresh starter wort and see what I get.
 
If the mold is all the way around the liquid and you don't want the yeast passing through it you could always decant the liquid and remove the slurry with a turkey baster or something similar.
 
If the mold is all the way around the liquid and you don't want the yeast passing through it you could always decant the liquid and remove the slurry with a turkey baster or something similar.

Good call, I like it. Yeah, the mold is only around the top of the liquid, so I think this would be a great way to do it. Thanks!
 
I had similar issues despite the fact I attached airlocks to my starters after ~18 hours of open air inoculation. One of the starters got black mold and smeller pretty awful, so I tossed it. Luckily when I stepped the other two starters after 3 weeks (trying to leave most of the white mold behind) the yeast took over and the mold didn’t reappear.

Yesterday I brewed 5 gallons of turbid mashed, aged hop, 3.75 hour boiled Lambic wort and pitched ~quart of each of the two successful starters. Hopefully it is rocking by the time I get home tonight.

Good luck!
 
I had similar issues despite the fact I attached airlocks to my starters after ~18 hours of open air inoculation. One of the starters got black mold and smeller pretty awful, so I tossed it. Luckily when I stepped the other two starters after 3 weeks (trying to leave most of the white mold behind) the yeast took over and the mold didn’t reappear.

Yesterday I brewed 5 gallons of turbid mashed, aged hop, 3.75 hour boiled Lambic wort and pitched ~quart of each of the two successful starters. Hopefully it is rocking by the time I get home tonight.

Good luck!

Thanks for describing your experience. Sounds like you successfully got the yeast without the mold! Good luck with your lambic. I'll keep you posted on how my little experiment goes. I think I'm going to try ReverseApacheMaster's turkey baster trick to extract my yeast.
 
The turkey baster method seems to have worked splendidly. After the kräusen fell on the small "capture wort" and things cleared a bit, I used a sanitized spoon to physically remove as much of the mold as I could. Then I took a paper towel soaked in vodka and wiped the inside of the jar above the liquid to clean things even further. Then decanted most of the liquid and used a baster to remove slurry.

I then inoculated a liter of new starter wort with the slurry, and it was going crazy within two hours. The thing is still going nuts and smelling quite nice. I think I'll brew up a 2 gallon test batch this weekend and see what I've got.
 
I think I'm in a very similar boat. I created a yeast starter last Sunday (5 days ago) for harvesting the bottle dregs from a pair of Russian River beers that I brought back from out of state, but I've developed a fuzzy white spot of mold on the top of the starter. I've created yeast starters a bunch of times before, so I was really surprised to see this.

You think it's safe to decant this off the top and pitch the yeast underneath on a flanders red I'm brewing this weekend?

IMG_0186.jpg
 
That's a pretty small mold patch, so if you can pour it off, I'm sure it'll be fine. If you really want to be on the safe side, you could decant more of the liquid and add more fresh wort. I'm going to guess the mold won't reappear, but it would give you the chance to find out before pitching it into a whole batch.
 
Thanks man. The problem I'm having is I have no clue how to tell if something is mold vs. a pellicle - I spent an hour or two looking at pellicle pics last night to see if anything looked just like mine, and while a few were close, I'm tempted to think what I've got is mold. Since it's tough to tell in the pic, it's about the size of a nickel, completely white, and looks like it has hairs - kind of like cotton.
 
Thanks man. The problem I'm having is I have no clue how to tell if something is mold vs. a pellicle - I spent an hour or two looking at pellicle pics last night to see if anything looked just like mine, and while a few were close, I'm tempted to think what I've got is mold. Since it's tough to tell in the pic, it's about the size of a nickel, completely white, and looks like it has hairs - kind of like cotton.

That's mold. Anything that looks "fuzzy" is almost certainly mold, and based on the picture you posted before it looks like mold to me.
 
Yeah, I'd say that's mold, but it's certainly not much of it. I would probably decant and try inoculating fresh starter wort with the yeast sediment. My mold was pretty successfully eradicated, I think, but I also stepped the yeast up before I pitch to a small experimental batch. I would be too nervous to put it in 5 gallons of a "real" batch, I think.

Let us know what you end up doing. Good luck!
 
I'm NOT experienced at this in any way, but my suggestion would be to go to a drug store and buy the largest syringe and largest barrel you can find, don't decant or disturb the liquid in any way and just put the syringe in the bottom of the jar and suck up yeast, then use a sterlizing wipe to clean the outside of the syringe and split up the contents between a few small starters.

Just a thought... Good luck.

This is interesting stuff :)
 
Ok, I think I'll postpone this brew for a week while I sort this out.

My plan is to decant about 80% of the liquid and get the mold. Then I'll rouse the yeast with the remaining liquid and pitch it to a new jug and add about a half gallon of 1.020 wort with just a leaf or two of hops. I'm hoping the lower sugar level, relatively high yeast content, and the preservative effects of the hops will allow me to salvage it. I'll give that about a week, as long as no more mold grows I'll try and use it next weekend.
 
Aerating wort also makes it harder for the mold to take hold in the first place, so if you have a stir plate or shake the new starter every few hours, that should also help.

That said, most sour bugs don't much care for aeration (unless you count acetobacter), so you'd be selecting more for yeast than bugs.
 
Ok, I think I'll postpone this brew for a week while I sort this out.

My plan is to decant about 80% of the liquid and get the mold. Then I'll rouse the yeast with the remaining liquid and pitch it to a new jug and add about a half gallon of 1.020 wort with just a leaf or two of hops. I'm hoping the lower sugar level, relatively high yeast content, and the preservative effects of the hops will allow me to salvage it. I'll give that about a week, as long as no more mold grows I'll try and use it next weekend.

I think that sounds like a good plan of attack. Definitely keep us updated on how it goes!
 
Quick update on this...

I decanted off the majority of it, leaving what you see in the first pic. The mold poured off just fine. I did notice the starter smelled strongly sour and fruity, which I considered to be a good sign the dregs took root, and you can see the layer of yeast on the bottom. I poured that into a sanitized pitcher and cleaned and sanitized the starter jug.

While I was doing that, I then took half a gallon of water, a cup of DME, and a pinch of some simcoe hops I had laying around, and boiled that for 15 minutes. I cooled that, and added it back to the original jug (I realized I didn't want to dedicate two separate jugs as 'sour'). I then pitched the yeast and dregs from the pitcher back in, and got what you see in the second pic.

Now - I wait a week, and pray no more mold develops.

IMG_0192.jpg


IMG_0194.jpg
 
Wow! I have no mold, but I do have a pellicle!

That was quick...

Holy crap, man. Congrats on getting rid of your mold. And congrats (I think) on the pellicle. I've never brewed anything that makes a pellicle. Do they normally pop up that fast?

My little 1.5 L wild starter has fermented out, so it'll be time to brew up a test batch with it this week. This is what I'm thinking (3 gal):

3 lb light DME
0.5 lb Crystal 20
1 oz EKG 4.6% AA (60 min)
OG 1.045-ish
IBU 20-ish

Not really shooting for a particular style or anything, just something to showcase the yeast character so I can judge what I have.
 
I also caught some wild yeast, after the initial yeast got going I pitched into a larger starter, its been two weeks and I tried it today it haas good aroma but a vinegar and sour taste. I did oxygenate the starter wort. Could that have caused the vinegar flavor and if I decant the liquid steal a small amount of the slurry and repitch into a fresh, non-oxygenated wort would I get rid of the vinegar flavor
 
I also caught some wild yeast, after the initial yeast got going I pitched into a larger starter, its been two weeks and I tried it today it haas good aroma but a vinegar and sour taste. I did oxygenate the starter wort. Could that have caused the vinegar flavor and if I decant the liquid steal a small amount of the slurry and repitch into a fresh, non-oxygenated wort would I get rid of the vinegar flavor

yes, that would work, acetobacter need oxygen to make vinegar so without 02 they cant do anything

you might still get a slight vinegar nose though as brett can produce low levels of it, though in my experience it ends up being more in the nose than the taste
 
I think a slight vinegar nose would be ok. It is slight in,taste right now, not very strong, I dont mind the sour in a lambic, or flanders beer, just dont want the vinegar flavor to overpower.
 
Quick update on mine - went to use my wild starter today and it had a small spot of green mold growing on the top, nothing like the white mold I had on the initial attempt. it still smelled good sour and funky, but it's not worth the risk.

At this point, I'm just saying screw it and throwing out the starter. Just pitching a smack pack of the wyeast lambic blend instead.

Unfortunate.
 
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