Howto: Capture Wild Yeast

I just started my version of this experiment as well. My plan is to take the wild yeast, and streak some on a agar plate, trying to isolate the yeast colonies from the other microbs. Then, I want to do a test batch with split fermentation, one with the wild cocktail, and one with an isolated yeast colony build up from the plate. I hope to let both age fairly long, and sample down the road side by side.

I think I will follow this agar plate method as well. At one point I had what seemed like a good layer of yeast sediment in my mason jars a day or so before the mold kicked in and ruined the batch. That appears to be the best time to take a sample.

How many days in would you say that was?

It was about 3-4 days. Within two more I started growing mold, so it was a pretty short window. It was my first effort though, so who knows... Gonna set up and try again tonight..

Cool man, thanks. I will let you know how my attempt goes. I put out my wort on Wednesday so I will check on it tonight. If there is any sign of ferment, I am going to cover with aluminum foil and put in a draft free area.

So I let the wort sit out for about 4 days, and plated a few streaks on agar. It grew for about 3 days, and there are defined colonies. I see some white (what I am believing is yeast) colonies, a definite mold growth, and some funky reddish/orange growths. Anyone have any idea what the red/orange circles could be?

Awesome thread, and awesome results.

Ryan PA, can you take a picture of your agar plate? I could have a look if you want.

I did the experiment too - poured some plates, containing

-10g yeast extract
-20g peptone
-20g maltose
-20g agar
-1L water

About 100ml per plate (big ones)

Left outside overnight, closed plate in the morning, grew at room temperature. After 2 days colonies started to appear. Most of them were filamentous molds, but also some white, shiny colonies. Picked colonies, checked them under stereo microscope, looked promising. Grew them in the same media overnight, but without agar and shaking in little erlenmeyer flasks at 25C.

checked under light microscope, and they were all bacterial :/

Interesting to see what was there, all kinds of stuff, but no yeast

Next try will be more serious. I think what would be good is to use indeed a media which is not too rich as I did. Maybe something which is selective. I am not a yeast expert at all but I am quite familiar with doing microbiological work. Any tips on plates which are a little selective?

Cool man, I will try to get a pic tomorrow when I am back home. I added hops to my wort in an attempt to promote yeast over bugs, but I figured that may be a non-point.

I left the plate out a little longer, to see if I get any more colonies.

I definitely went over the top with those sugars. Next try will be less half-assed. I will also wait until it cools down more, bacteria will outgrow anything now here. Just a few more weeks, then more minimal media (no sugar, maybe just soluble starch or something), and maybe a trial with fruits thrown in.

Ryan_PA said:

Cool man, I will try to get a pic tomorrow when I am back home. I added hops to my wort in an attempt to promote yeast over bugs, but I figured that may be a non-point.

I left the plate out a little longer, to see if I get any more colonies.

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any pics yet?

Sorry, I have been slacking. I will try to get some pics up late tonight.

Has anybody tried it indoors...say in your kitchen? or around a bunch of sour beers fermenting. I've always wondered if/how much Brett leaks out out of closed fermenters.

Sorry for the delay. I think this plate may be a total loss since I took too long to try to culture from it and the mold has taken over pretty good. Even through the glare, condensation and crappy iphone resolution, you can see the orange/red spots I was talking about.

Yea same thing happened to me... waited too long... Haven't gotten around to trying again, even though right now would be perfect, as its in the low-50s every day now... I've been using all my DME for starters lately though...

Although at one point while trying this, my jars that were sitting out for a week seemed to be growing this really interesting yeast.... It almost looked like... maggots...... haha.. Yea, I wouldn't let that plate sit around for too much longer. Not a fun mess.

There seems to be all kinds of stuff. Indeed, just tape your plate of with some tape or put it in a ziplock and just dump it in the fridge when you see enough.

I put a week ago a glass outside with some low sugar malt extract from a batch I made, watered it down a little to get the sugar down. Hopefully this will work, otherwise I will just go for the bread yeast starter technique.

Are just the colonies red or is the color diffusing into the plate? Some yeasts produce red colonies - but some bacteria too. In some bacteria the red color diffuses out of the cells and you can see a halo around the colony.

It was just the colonies. I ended up making a few small starters last night with the very few isolated white colonies I could get to. I just used 30-50 ml of wort for 4 separate starters. as of this AM, there was nothing to be seen, not even a surface bubble. I will give them a day or two...

I tossed the rest of the plate since it had a "unique" aroma when I pulled the colonies. I will keep the thread posted with any progress.

I also made 2 more wort starters and put them in my sour fermentation room. i will see if I get anything in there.

One of my small starters has now been bumped up to a 500 ml starter.

I tried a different approach. I put a beaker with sterile, low sugar conc. wort outside for two weeks.

I took ~5ml of that, grew all kinds of stuff, mixed that with some water and flour, and waited 24 hrs. Did the whole sourdough refresh thing every 24hrs for 3/4 days. It started to ferment, and smelled pretty bad. I used it to inoculate high sugar medium, YPED with maltose (small scoop of dough in 300ml). Shook overnight at 30 degrees.

Did the same for a "control", just flour with water, and also the sourdough procedure. Also that started to ferment, actually faster and harder. Also added that to the high sugar medium (maltose).

Next day two cultures grew, and smelled really "bready", the same smell you get for certain yeast starters. I checked under light microscope, and the one I started from the outside culture contained 80% bacteria, 20% yeast, if not less yeast, the other one was about 50-50. The bacteria were different clearly, but the yeast seemed similar (I have seen different yeasts look different but these were indistinguishable). I plated each with an ocular hook on agar plate, to see what I got.

The reason I went for this approach is that the beaker with wort smelled super foul, and contained a lot of fungus. I just do not know how to select for yeast. Maybe where I live is just bad..

I only hope I did not get Candida milleri - since it can not metabolize maltose.

A minimal medium test will show that pretty quick, in the future.

I also went to an apple orchard, picked a few apples and tossed those in medium, as a backup.

If it does not work, I can always make some nice bread

Been thinking about trying this again now that the weather should be cooperating soon. Occurred to me that in addition to hopping the wort around 10 IBU, and adding some acid to lower the pH, I could also add some Everclear to the wort to get it up to about 3-4% ABV. Most bacteria will not grow above 3-4% ABV. The hopped, acidic wort with alcohol in it would be most friendly toward the beasties that I want to isolate -- brewers yeast and brettanomyces. Several propagations with an acid wash in between each should help to minimize any remaining bacteria and other contaminants leaving just pure yeast. If that fails, I can always streak some plates to isolate colonies of yeast from bacteria and mold.

At face value, that seems like a heck of an idea.

Saccharomyces said:

Been thinking about trying this again now that the weather should be cooperating soon. Occurred to me that in addition to hopping the wort around 10 IBU, and adding some acid to lower the pH, I could also add some Everclear to the wort to get it up to about 3-4% ABV. Most bacteria will not grow above 3-4% ABV. The hopped, acidic wort with alcohol in it would be most friendly toward the beasties that I want to isolate -- brewers yeast and brettanomyces. Several propagations with an acid wash in between each should help to minimize any remaining bacteria and other contaminants leaving just pure yeast. If that fails, I can always streak some plates to isolate colonies of yeast from bacteria and mold.

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Good idea about the alcohol. I will try that too. I actually added some lemon juice, I forgot to say that, to bring the pH down to hamper bacterial growth.

I put some pictures online for those interested, on this ghetto website:
http://jaapie.org/wp-content/uploads/beer/

The 2 week wort culture smells really sour, the other smells really estery, fruity.

I picked isolated yeast colonies of both plates, and inoculated small volumes minimal medium with maltose (hopefully no C. milleri) and rich medium to isolate the pure strain. I stocked the mixed cultures for further usage.

Would putting some salt in the capturing wort help to reduce the chance of mold forming?

this should go under the category of "Cutting brewing costs". since i live in the middle of 40 square miles of wine country, ima have to go nab some grapes and see what we'll see.

perhaps a starsan (acid) wash once fermentation started pretty good?

I have a question, how do you determine what temperature to ferment your wild yeast at?

Most molds can withstand high salt concentrations, yeast can deal with that better than bacteria (on average of course), but mold will win. I would not wash with starsan, it is pretty aggressive to anything including yeast. If you think you have yeasts streaking should work.

Wild yeast basically means that you dont know what you have, so its impossible to say what temperature would be ideal. It also depends on your wort and what you want to achieve. Yeasts are grown (mostly) optimally at 30 degrees C, but optimally for yeast is maybe not optimally for the taste and the Topt depends on the species too. I would go for between 15 and 20C just to try.

In the mean time I have two pure cultures of wild yeast going, one I made into a 2 liter starter, and the other I will do tomorrow. Cultures grow on minimal medium with maltose, but supplemented with amino acids. I am trying to grow them on minimal medium with maltose without amino acids, but have not seen anything yet. I dont know if that is a good sign or not.

Update: Wild yeast strain 2 grew in minimal medium with just maltose (nitrogenbase and maltose).
UpdateII: Wild yeast strain 1 grew too in minimal medium.

Cool thanks for the info. I've got two starters going at different temperatures (62,65) right now. I'm going to sample the starters and determine which I like better. Then go into a full scale test. Guess the taste test will tell me all I need.

How do you regulate the temperature of your starters? Just interested. Those temps are pretty close too, less then 2 centigrade, let me know if you can taste a difference.

Well actually I changed it to 62 and 68. I used my fridge that was set at the Ale Temperature (68) to do the one and then I did the other (62) one in my SoFC where I do lagers. I got temperature probes to the side of the flasks with a patch of paper towels to insulate it from the ambient air temp.

Thats great, i need something like that. I am just fermenting in my garage.

Well just got done with the taste test and I think I'll go with the 62 degree wild yeast.

The 68 degree one has a lot of sour and I taste a little hit of fuesel alcohol. I think that my be the high end of the yeast fermentation temp. It also appeared to ferment out faster that the 62 degree. Now I didn't take a gravity reading, but it showed the visual sign of going from the dark malt color to the chocolate quicker.

The 62 degree has a hint of the sour profile as the other, but taste cleaner than the 68. It has a sulfury smell with it, but it does seem any different than say a WlLP029 German Ale which my notes list a sulfur smell. White labs website say the sulfur created by their German ale will go away so I'm hoping mine will too.

So I'm going to ramp up to a bigger starter and then brew a partial this weekend with the 62 degree yeast.

Freezeblade said:

I've had great success with capturing wild yeasts from the skins of fruits for use in cider, my process is simple:

get an organic fruit (so far I've only done stone fruits and apples), try not to touch it with your bare hands as much as possible. Skin the fruit and place the skin into a 12oz bottle filled half-way with apple juice and a little yeast nutrient. cover with foil and shake it around every few hours or so (I don't have a stir-plate) and keep in a warm place. Once you see some good fermentation happening (3-4 days usually), shake around the starter again and transfer the liquids and trub to another 12oz with a bit more juice in it, leaving the skins behind, let starter ferment through for a few more days, then pitch into your wort/apple juice. After that batch is done, I usually wash the yeast to use again. I've found that the first batch is quite "dirty" and cleans up after subsequent washings and refrigerations. YMMV.

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I have an apple and pear orchard as well as 75 grape vines. That's the idea really -- take the yeast off of the skin of the fruit. The yeast is the white stuff found on freshly picked fruit. Generally speaking you want find much on supermarket bought fruit but fruit when picked direct from the tree often has a white layer on it, which will leave you can leave evident fingerprints. European prune plums are fantastic sources of yeast. I know this is the case up here. It is generally rainy, snowy, and foggy and generally never hot except that it can get humid; great conditions for airborne yeast. 50F is definitely the temperature to go hunting for yeast.

Your location certainly has an effect on the yeast and bacteria you capture. I've made plenty of sour dough starters. And, you certainly do get different results at different times of the year (especially if you also happen to have a blueberry bog at the back of your land). The Portuguese guys around here open ferment wine leaving the grape skins in contact with the juice for several days. The wine develops a 'flor'... a white scum across the top.

As a casual observance you might notice that cheese goes moldy quicker at different times of the year. Another thought I've had is wiping nectar rich flower petals onto an agar media or even throwing them into a wort sample. Buttercup flowers come to mind. I thought of this as my brother the beekeeper makes his wine from teeth of the lion flowers -- fermenting the nectar on the flower heads. It comes out like sprite or 7-Up. If it's at all easier.... just squash a pollen laden honey bee and wipe that on a plate. Wild honey is loaded with yeast too (from what I understand) the bees might be carrying it around.

Id say you get in camo and wait in a bush for awhile until some yeast show up and shoot em with your rifle ....

FireNightFly said:

Id say you get in camo and wait in a bush for awhile until some yeast show up and shoot em with your rifle ....

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I'm suitin' up right now.... Now, where'd I put that old sea bag with my gear in it?

I have two 5 gallon batches going right now, both strains are clearly different, one is super flocculant, the other not at all. Both are ragingly active. I will let you know what comes out...

talenos said:

I hear the wild yeast in Southern California smells like nail polish remover, but this would be fun to do.

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Well, I'm in southern california, and I think I got some of that... smells EXACTLY like acetone, and strong too.

I had about a half a gallon of left over beer that didn't fit into my carboy, so I threw it in a gallon iced tea jug, one of the ones with a pretty wide, open top. This was after primary fermentation was done and I was going to secondary with it. After a few days, it ended up with a powdery white spider web-like layer on top of it. After a few more, it dropped, and hten came back. At this point, it smells exactly like acetone. I'm a little afraid to try it at this point.

strange. i had a slant get a powdery colony on it. looked like mold but was definately 1087 ringwood. but i got scared and put it in the cooker 30min at 20psi.

THE WHITE FILM IS NOT YEAST, DO NOT MAKE BEER WITH IT. It's either bacteria or mold.

I started this experiment awhile ago and I got good results. I brewed a belgian strong ale last spring and filled a pint glass about halfway full of wort and put a hop bag over the top and let it sit outside last spring for about 3 to 5 days. I got some good growth, no mold or nasties and poured everything into a clean and sanitized mason jar. I didn't really work on the recipe that much, just grabbed some DME and cascade hops (would of been better with a wheat recipe) and dumped the mason jar contents into a one gallon gatorade bottle with some foil over the mouth and let it ferment FOREVER. I then racked it into a mrbeer and filled the bottles with the right amount of sugar and kept the yeast from the gatorade bottle (I'm feeling a 5 gallon batch coming on!). It taste pretty good right now! Its pretty easy and gives you a interesting batch of beer! Now I got a half a mason jar of my own "stuff"