Those of you who follow me on Twitter have had your ears bent about this topic quite a bit lately, but it’s so exciting I just have to share it, you know?!?
I’ve been slowly (veeeerrrryy slowly) chugging my way through Chris White & Jamil Zainasheff’s book “Yeast” recently; it’s fascinating stuff, and has inspired me to try my hand at some yeast wrangling in my own backyard. As you may or may not know, once upon a time all beer & wine was fermented solely with the wild yeasts that were found on the ingredients used, or that fell in from the air around them. The folks back themn had no clue that yeast even existed, but that’s another tale entirely.
So I started trolling the interwebs for information of home brewers who’d actually tried to catch their own local , wild yeast; I was surprised that there’s not too many who’ve done it, and many who had were far from successful. But I was not to be deterred!
(btw, I say “yeast” because I have no way of knowing at the moment whether I have caught yeast or a bacteria that acts like yeast!)
Here’s how I “caught” the yeast, and how I’ve used it so far:
First of all I brewed up a batch of starter wort (1/2 cup pilsen light DME & 2 cups water), placed it in a sanitized mason jar and added a couple of pellets of hops (to keep the mold spores at bay)I then covered the jar in a fine mesh painters bag.
The covered jar then got situated in a planter pot outside in the backyard, somewhere out of direct sunlight where my lovely dog Chuck, would not knock it over. I left it outside for a full 48 hours.
My trusty flask and stirplate came out for a spin next, so I could see if I’d
caught anything viable, or if this little exercise was a bust. Surprise of surprises! I got activity within a couple of hours! I washed out the yeast (procedure for another post), made a new batch of starter wort and stepped-up the “yeast” to cultivate a larger number of cells by feeding them wort. I did this 4 times over before I thought I’d have enough cells to pitch into a 2 gallon starter batch.
Once I had enough “yeast” to make a batch of beer with, I brewed up a 3 gallon batch of fairly innocuous, low gravity (1.032 OG) wheat beer. I wanted it to be as blank a slate as possible, so that I could really get a feel for what flavours I would get out of the wild “yeast”. I split the batch into one 2 gallon carboy and a 1 gallon growler; the 2 gallon batch got the starter I had made pitched in and the the other batch was bound for the backyard to catch it’s own inoculation of wild “yeast”.
I covered the top of the growler with a small mesh hops bag, tied it up tight so no critters could get at my liquid gold! My Ladies of Craft Beer tee covered it from direct sunlight and it went out under the rose apple tree for 48 hours. After only 24 hours, a light krausen was forming already.
I brought it inside when the 2 days was up , put an airlock on it and let it go. The krausen formed thick and fluffy and fermented up a storm! The yeast cake that formed on the bottom of the one gallon growler was huge for such a small container.
So now both are done fermenting and it was time for a gravity test and a taste. Batch #1 is down to 1.002 (3.9% ABV) tastes a little funky with a slightly leathery aftertaste; from what I read, this particular taste is common with Brett, so maybe I landed something extra-special-funky with this one. Batch #2 is down to 1.004 (about 3.5% ABV) and tastes cleaner, fruitier and more saison-y. There’s also no leathery aftertaste on Batch #2.
Batch #1 is developing a pellicle as of this week, so that could certainly be cause for sour excitement! Batch #2 still looks clean. If it doesn’t develop a pellicle in the next week or so, I’m going to bottle it and forget it for a while.
I brewed a higher gravity beer (IPA grain bill) 2 weekends ago to throw on top of the Batch #1 yeast cake to see if it could tolerate the higher alcohol wort; I think we can all agree that if a beer goes from 1.070 OG to 1.003 FG (8.9% ABV) in 3 days, that is has the chops! I haven’t ever seen yeast chew through sugars that fast….even champagne yeast! Tasted it and we have much the same characteristics as the original Batch #1, still with a little leathery/tobaccoey thing going on. I have high hopes it will improve with age. Batch #2 is more exciting though, as we might have something with no bugs ad makes a lovely, light and saisony type ale – perfect for a Florida house strain!
I’m really excited that I ended up with two pretty decent tasting “yeasts” out of this experiment, maybe some native bugs and no mold! Would love to hear any stories about anyone else out there who has tried this kind of experiment – successful or not! Will keep you updated on tasting notes etc down the road 
You won’t necessarily get a pellicle unless oxygen is introduced to the beer, which would likely occur by sampling the beer. A CO2 blanket would prevent this from forming.
True, but it’s been opened and tasted a couple times already…probably enough to have sufficient O2 to form a pellicle. We’ll see what happens in the bottle if it doesn’t! Best lightly carb this one I think
Nice job! Your going to learn a lot doing this. Hopefully you won’t learn the hard way about sanitation too. Since your dealing with many unknown organisms take extra care to soak your equipment in sanitizer.
Good luck, can wait to hear how they turn out.
Cheers
Thanks! It’s fun stuff
And seriously; Cbrite has been my best buddy lately!!
I have captured some wild yeast from my yard via dropping some grapes I grow into some fortified (with sugar and yeast nutrient/energizer) apple juice. I did a few different test jars and tossed the ones that didn’t ferment or grew mold.
From there I did a small light flavored batch similar to yours to more easily detect any weird characteristics from the yeast, it actually turned out fairly clean tasting with a grassy aroma. I was slightly disappointed that there wasn’t any real funkiness, but also pleased with the results.
I’m now brewing a 5 gallon batch of Belgian style Wit with my wild strain. I’ve also donated it to a local museum’s brewing archaeology seminar.
That’s fantastic; cool that it’s going into a museum too! So many people told me it was useless to try this (especially in humid SoFL) but I seem to have had pretty good results so far!
You’ve had amazing results! From what I read around the net setting an open jar out is a great way to catch mold, which is why I went with the fruit. I’ll be very interested to know how your beers turn out.
Where is your control? How do you know the yeast you’re using came from your yard, and not from the flask? Next time, split your media into two flasks, inoculate one with the wort you exposed, and another with wort you never unsealed after sanitizing. Then you can be more sure the yeast is wild.
Well, the flask was well sanitized before I added the wort and put it outside, so where else would I assume it came from? I’m no scientist, but seeing I sanitize carboys etc before adding wort before fermentation, and have never ended up with a wild infection in my beer, wouldn’t the same hold true here?
Happy to be corrected if I’m wrong though!