What Wild Yeast and or Bacteria do i have?

[rwabdu]

I'm going to try to brew a Lambic next week. I captured some wild yeast a while ago and was going to try to use it. But how can i figure out what yeast strain I have and if it will be good for beer? I have two that seem like good cultures, but one started growing mold, how do i get rid of mold?? neither smells particularly good, one smells spicy.

also, I want to make a sour beer, if I understand correctly, I neet bret for sour beer? how do I know if i have brettanomyces and if not, how can i catch it? I'm trying to do this with wild cultures, nothing store bought.

 

[bob3000]

I havent much experiance with wild yeast but I have tried to catch my own and asked quite a few questions on this forum.
The concensus seemed to be the only way to find out way yeast you actually have is to try and isolate different collonies on agar plates and to do this would take some skill and investment in equipment.
Otherwise, you just have to ferment out an experimental batch with low IBU to see what happens.
When I captured a colony I left a jar of wort to ferement out for a couple of weeks and tasted it regulary. I noticed the taste changed several times over this time. It went from something fairly normal tasting then picked up some spicy weissen flavours then morphed into full on sweaty horse blanket.
I bottled the beer even though it tasted pretty rough and I'm going to taste a bottle every month or so to see if it changes into anything usable.

After a 2 months it is already developing a sour flavour but it also has a lot of other unpleasant off flavours.

From my understanding, if you have wild fermentation chances are you will have a brett in there along with several other strains.

 

[ReverseApacheMaster]

It is sort of crap shoot to figure out what you get. Sometimes you'll get something neutral, sometimes something really nasty. It will definitely be unrefined compared to brewing yeast since you're getting a mix of random stuff out of the air. You will most likely get brett so long as you wait months for it to appear.

In my wild culture there is no sourness. I also hopped the starter I used to catch the yeast so it would have kept a lot of sour-producing bacteria from growing. If you want sourness you may want to avoid hops.

I know a lot of people go with the open air approach (letting whatever falls in the wort grow) and while I think it probably gets the most complex and interesting blends of critters it may not produce the most enjoyable. Personally I used fruit and I'm fairly happy with what I caught. People who use fruit tend to get more neutral but pleasing results.

It's all about experimenting. You may have to take multiple samples before you find anything you enjoy.

 

[rwabdu]

Ok great thanks for the help! I got 15 agar plates (have some biochem experience) i have a few cultures that seem promising, ut my favorite grew some mold. im pretty worried about how to deal with mold. maybe if i get the alcohol high enough the mold will die? i guess ill make a batch this week and see what happens

 

[El_Exorcisto]

Molds won't actually colonize your beer since they are aerobic, so about that just run with it. As for sour, brett is a part of belgian sours but is not a required part of sour beer in general. Berliner Weisse is a sour beer that work off sacc and lactobacillus exclusively. The Belgian sours use pediococcus which can survive much lower pH than lactobacillus but also produces a lot of diacetyl.

The brett and pedio have a symbiotic relationship in the Belgian sours. As the pH drops, the brett begins to superattenuate and break starches into monosaccharides. The pedio consumes them, producing lactic acid. The lower the pH drops, the better the brett's invertase works. The brett also consumes the diacetyl, cleaning that off flavor up.

Lambic brewers also use oxidized hops that are devoid of alpha acids but high in beta acids. These beta acids protect the beer from being colonized by lactobacillus but add very little flavor. If lactobacillus takes hold too soon the pH can drop too low for saccharomyces yeast to colonize.

 

[ReverseApacheMaster]

Ok great thanks for the help! I got 15 agar plates (have some biochem experience) i have a few cultures that seem promising, ut my favorite grew some mold. im pretty worried about how to deal with mold. maybe if i get the alcohol high enough the mold will die? i guess ill make a batch this week and see what happens

Unless the mold has taken over the agar plate you should be able to remove some of the yeast from the plate and streak it on a new plate.

 

[rwabdu]

Yeah my plates have mold free colonies, but my starters have some mold growing in them. I tried to get it out with a spoon. Thinking ill try to make some new cultures tomorrow and see what I get as the weather has warmed up a little now.

So if i understand it right, if i let my beer ferment naturally, Bret will probably develop and take over if i wait 6 months?