Howto: Capture Wild Yeast

Very cool thread! Going to see what I can grab here in the Boston area!

Hi all,

This is my first posted question to HomeBrewTalk. A few months ago, I started eyeing the instructions in the first message with longing to try, and am now biting the bullet! I have a couple questions related to the yeast capture process and where / how to use it.

First, my jar of wort in the window is now just over three days old -- at the point where the lit. suggests it should have colonies of enteric bacteria and kloeckera. Today when my wife and I smelled it, it smelled like a cross between sourdough bread and yogurt. (Lactobacillus?) Is this OK at this stage? I guess I should add that part of my goal is to brew a sour beer from multiple "wild" organisms, so I'm not opposed to adding lacto per se -- only concerned if this means the capturing process will likely fail to get saccaromyces at this point.

Second, my plan to this point has been to capture some wild yeast through the open window of my appartment in Pittsburgh, PA, then add that yeast + brett from the dregs of Victory's Wild Devil (+ perhaps the dregs from other sour beers from friends, if they're willing to donate closer to brew day.) Are there any details I should pay close attention to if I do this?

Thanks for any feedback! This is the first time I'll be trying to brew a sour beer, and any feedback is much appreciated!

-- Matt

Yes, it's ok. You could have any number of things that will smell like all sorts of stuff.

MattTimBell said:

Hi all,

Today when my wife and I smelled it, it smelled like a cross between sourdough bread and yogurt. (Lactobacillus?) Is this OK at this stage?

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That's great! Low pH favors the growth of saccharomyces by preventing competition from most bacteria and molds. When I do your technique of leaving wort out to catch wild bugs, I add lemon juice until the wort is around pH 4. You've just let acidifying bacteria do the trick for you.

MattTimBell said:

Hi all,

Second, my plan to this point has been to capture some wild yeast through the open window of my appartment in Pittsburgh, PA,

-- Matt

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My only advice is to put the wort in a place where insects can have access. Yeast isn't just floating around in the air -- it is carried around from one sugar source to another by flies, beetles, and any other bug that likes to eat sugar. So remove the screen from your window, or hide the wort in the shrubs outside your apt. or in a nearby park.

Thanks, all! An update and a couple more questions:

My only advice is to put the wort in a place where insects can have access. Yeast isn't just floating around in the air -- it is carried around from one sugar source to another by flies, beetles, and any other bug that likes to eat sugar. So remove the screen from your window, or hide the wort in the shrubs outside your apt. or in a nearby park.

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As of last night, it was bubbling, although with no sacc like foam on the surface -- and I had it away from sacc carrying bugs and the time. (But, not anymore, thanks!) I wasn't aware lactobacillus made CO2, but this really smells lacto. Could that be a species of lacto, or is there something else likely in there or taking over?

Also, should I add more sugars to the fermenting mix every so often until I get sacc, as whatever is making the CO2 eats those already there? What would be a good source? It occurred to me from the comment on allowing access to sugar-loving insects that local honey might both supply food and yeasts. Would local honey be a good source, or would that likely add harmful bacteria?

Thanks again! Watching this stuff and learning about what's going on in it is fascinating!

In my experience, it's a little hard to predict what bugs are in an open fermentation. Every bug makes CO2 to some degree (for the same reasons we humans do), and even if you do have sac, they may not make the same krausen they would make if you isolated them and pitched a large number. Sac and lacto can grow at the same time in a wort -- they might even help each other (Sac poisons competitors with alcohol, lacto poisons competitors with lactic acid, they are both tolerant of the other's poison.)

If it has been about a week, I would take a bit of the fermentation and put it in the fridge (or mix with 15% glycerol and put in freezer). You can save some again in a week and keep on saving samples every week for as long as you'd like. It should start to get very sour after a month or so. Then pick a sample to grow up to pitching quantity and make your sour beer, or dilute them 1:100 or 1:1000 and grow a bit on a plate if you want to try to isolate yeast.

Honey usually contains more osmotolerant (can survive high sugar concentration) yeast like Zygosaccharomyces, but don't let that stop you from giving it a try. We once thought of Brettanomyces as a spoilage yeast, so I wouldn't rule Zygo out!

Hey folks! Thanks for the advice on how to treat the evolving yeast-capture. It's now one day over a week old, and continuing to change. I'm curious: what scents, appearences, etcetera, indicate an UNhealthy development? Yesterday, it smelt of strong cheddar; today, of cheddar in slightly rancid water. Is this autolysis of whatever was growing in it? Do I need to throw it away and start over? Take a sample from it and add that to some fresh weak wort to continue until I've captured all I want?

Thanks! -- Including for your patience with all these questions.

If you have something undesirable in there, transferring a sample to new wort will just produce the same results.

You will know when you have saccharomyces because it will smell, well, like fermenting beer. Otherwise, you just have a jar of bacteria. Now it's only been a week, so there might be yeasts waiting for their turn to play once the pH goes low enough. However, the bacteria might consume all of the sugars before the yeast can take their turn, causing no yeast growth. You may need to add more wort or sugar and aerate it to see if you get some yeast-like activity in the next few days.

My wild yeast experiment developed a wicked pellicle about 3 weeks ago. I wonder how it will come out.

Someone mentioned "evolving" the yeast. I propose the experiment below.

0. Harvest wild yeast if you don't already have a culture.
1. Pick a recipe and brewing process that you will use consistently over this experiment.
2. Brew beer with wild yeast in 5 1-gallon containers.
3. When they're ready, pick one or two that taste best to you (it will probably take several iterations for there to be a noticeable difference) and brew 5-10 more gallons with those cultures, again keeping them separate from one another. Discard or store the unused cultures.
4. Repeat step 3 until you get bored or until you've got a culture that makes something you really enjoy. Use it to brew some or all of your beers, and enjoy your home brewery's very own exclusive yeast strain!

This is essentially selective "breeding" and it's been used by agriculturists for centuries. I'm thinking this would be a very long-term experiment, on the order of years. Depending on how many strains you isolate each time through, you'd also probably wind up with tons more beer than you could ever hope to drink.

Anyone want to give this a shot??

Another, much easier way to capture wild yeast is to use un-pasteurized honey. I have a post detailing my first wild brew, using mostly yeast from some local honey from Newport, NY. Look for honey with some white foam growing on the surface. Best I can tell, the white foam is a miniature krausen.

Love this thread!

My results, using a few ounces of leftover wort from a recently brewed Old Ale. I wasn't sure what to expect using a high gravity starter, but after 3.5 days:


And after 6 days (and it smells great):

Sweet! Is the stuff on top just bubbles or is it a pelli of some sort?

ericd said:

Sweet! Is the stuff on top just bubbles or is it a pelli of some sort?

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It's a layer just sitting there, looks sort of krausen-like, but no bubbles or 'movement' to speak of. It went from pic one to a full layer covering the glass in one day, and grew in thickness after that. Anyone had similar results?

electric_beer said:

Yeah, seeing chilli BUBBLE actively was pretty nasty. However the successful capture seems too be looking good. Just gotta hope I don't get any mold!

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I hope that you collected some of this yeast for beer making! Could make a great Green Chili Ale!

~M~

It's krausen, it's the way all of our wild yeasts look as long as they arent on a plate.

I want to attempt to gather some tasty yeasties in my area. I noticed that there are a number of fruits that tend to collect yeast on there outer surface (grapes, plums, etc.) does anyone know if these are good sources of beer yeast or if I should stick to the air capture method?


Thank you!
-AjnachakrA

Culture the fruit, it is WAY more consistent than capturing from the air.

Grapes are supposed to be an excellent place to get wild yeast.

Update: Sorry it's been so long since I posted here last, but my wild yeast mead turned out excellent (I didn't step up the yeast in the sample, and it took a year and a half to grow to proper mass and ferment the test batch)

It's not as strong as the champagne yeast that I normally use (seems to be the only fermenting yeast I seem to be able to find here in Calgary, AB) but it left the mead very sweet and aromatic. It cleared beautifully (Just as good as the champagne, which surprised me)

I don't usually take gravity readings (Sorry!) but my vinometer says it's coming out at about 7 1/2% - 10% alcohol (I don't know how reliable vinometers are, but it sure doesn't taste at the normal 15% that it usually does). It oddly enough, tastes like a spring day in Calgary...

I have to say, getting weather stable enough here in Calgary for two weeks was more of a challenge then actually capturing the yeast itself. I lost a few initial attempts due to the weather suddenly getting too warm and it sprouting mold. As it was, the initial sample went to mold, but not before I extracted 10ml of yeast floating in the bottom of the capture jar with a syringe my wife stole from work for me.(I <3 my wife). Risky, I know, but the test batch (.75 gallon - a weird size I know, but I had to work with the carboys I could find) turned out fantastic.

I have since used the yeast from the test batch, swirled it around in the bottom of the little carboy, and added it to a new 3 gallon batch that I started for this purpose.

It's been four days since I started it, and I've noticed that it's forming krausen on the top of the batch. I've never seen krausen before, and it scared me because I thought it was forming mold. But research shows that it's alive and well, and it will subside as the batch ferments.

It's not producing any noticeable CO2 that I've seen (i.e. the bubbler isn't bubbling, but it's pressurized like it wants to) which, considering my inital batches were with bread yeast, and later with champagne yeast, is a little unnerving. But the fact that every morning, something new has happened in the carboy tells me that it's doing something. Good or bad, well I'll have to wait and see...

Thanks again for starting this awesome thread. It's took my mead making in an entirely new and exciting direction.

Wow! I just read all 44 pages of this today and really want to give this a go when it gets a little nicer here in Idaho. I am thinking a nice saisson made with my local yeasties would be awesome!

Is it possible to culture yeast during cold months?

it's actually easier to get a culture of yeast growing when the temperature outside is around +2°C for about two weeks straight. Much more then that and it becomes too much of a breeding ground for mold (At least, that's what happened to me)

WilliBChrist said:

it's actually easier to get a culture of yeast growing when the temperature outside is around +2°C for about two weeks straight. Much more then that and it becomes too much of a breeding ground for mold (At least, that's what happened to me)

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I captured my wild yeast at about 42 F here in DC.

I stepped it up twice and left it uncovered on the kitchen counter for a month (well, cheesecloth loosely placed on top of jar). I just pitched it into 5 gal of Belgian Pale Ale wort on Friday and it was chugging away after 8 hours. Smells good & the krausen looks just like every other primary ferm. with a laboratory yeast.

dcHokie said:

I captured my wild yeast at about 42 F here in DC.

I stepped it up twice and left it uncovered on the kitchen counter for a month (well, cheesecloth loosely placed on top of jar). I just pitched it into 5 gal of Belgian Pale Ale wort on Friday and it was chugging away after 8 hours. Smells good & the krausen looks just like every other primary ferm. with a laboratory yeast.

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yeah, you're right. I just had problems here in Calgary if the temp went above 2°C to 3°C (35°F to 37°F).

dcHokie said:

Smells good & the krausen looks just like every other primary ferm. with a laboratory yeast.

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For anyone interested, here is a pic. The BB fermenter in the background got the wild yeast (foreground is other half of the batch that got a 1.5L wyeast starter).

That looks absolutely fantastic. I wish I'd taken pictures when I stepped up to a full batch of mead now.

This is very intriguing, I might have to try this once!

just read the whole thread, amazing. going to start my own project. thanks to everyone...

Just posted an article on my blog about my adventure in yeast wrangling if anyone would like to see another success story

http://potablesandedibles.com/2011/02/homebrew-wild-yeast-experiment.html