Category: Wild yeast

Washougøl is a beer that’s inspired by Norwegian Maltøl. If you’re unfamiliar, Maltøl is an indigenous Norwegian farmhouse beer style. Traditional brewers use juniper branches to make an infusion and use that as their strike and sparge water, often juniper is used in the mash vessel as well to create a filter. These beers are very lightly hopped, if at all. They are fermented with landrace yeast that’s been handed down in the families and villages for generations and is known as kveik. You can read a lot more about this sort of beer and the different kveik yeasts over at Larsblog.

Maltøl is a bit of a catchall blanket term that encompasses a few different sub-styles that exist in Norway. Since my own version deviates in a few ways from these sub-styles that I’m aware of and since I live in Washougal and not in Norway I’ve called my beer Washougøl. Anyway, let’s talk about the differences and my thoughts/reasons behind them.

Juniper. Juniper is a staple in Norwegian farmhouse brewing, indeed it seems to be a staple in nearly all indigenous Nordic brewing from Norway, Sweden, Finland, the Baltic States and probably into Russia as well. The species used is Juniperus communis which is super abundant in these areas. Brewers basically cut a few branches from their hedge or whatever and they’re ready to go. While Juniperus communis does grow in certain parts of the pacific northwest it’s not incredibly abundant and mostly grows at the higher elevations of the Cascade mountain range. Instead of driving up to the mountains I decided to use an evergreen that’s very abundant on my property: Leyland Cypress. Leyland Cypress is a fairly common hedge tree in suburban PNW. It also makes a delicious tea as well as beer. For this beer I cut a few boughs and used them in the mash and also to make infusions for the strike and sparge water.

Hops. In traditional Maltøl hops are very restrained or even not used at all. They are typically homegrown or procured at the local pharmacy.  For my Washougøl I used only homegrown Glacier hops (partly because I have a shit ton of them) to give just a touch of bitterness to the brew and help beat back lacto. I suspect my Glacier hops have a rather low alpha acid in the 2-3% range, but I aimed for an IBU level of around 12 using hops in both the mash and toward the end of the boil.

Kveik. Kveik is yeast that has been passed down for generations from brewer to farmhouse brewer in Norway. While kveik is starting to become available to brewers around the world and is certainly an option for Washougøl, it wouldn’t be especially Washougally to use yeast from 5000 miles away. Instead I chose to use my local wild yeast culture that I’ve been using for 6ish years now. It’s obviously not handed down from my great grandfather but it does seem to be the dominant yeast in this area and it makes delicious beer, I’ve been using it for a while and it’s one of my favorite yeasts. You can be sure, if my daughter takes up brewing I will be handing it down to her.

Malt. In traditional Norwegian farmhouse brewing the malts were made on the farm. This is mostly due to a long standing Norwegian law left over from temperance times stating that anyone wanting to homebrew had to do so with homemade malts. A previous even longer standing law said any farm in Norway must produce beer. Both of those laws have been repealed in Norway and while some farms do still produce all the malt they brew with, most just buy pilsner or pale malt from continental Europe. For the Washougøl I used locally malted Superior Pilsen from Great Western Malt and Rimrock malt (a sort of vienna style rye malt) from Mecca Grade in Oregon. Rye is actually more common in Finnish Sahti than Maltøl but I wanted to give a little of that rye mouthfeel in this beer that I knew would be quite dry due to my (likely) STA1+ yeast selection.

Process. Maltøl is typically not boiled at all, though one sub-style boils for around 4 hours. I boiled Washougøl for one hour. I didn’t go for a raw ale because I want this beer to have a longer shelf life. Raw Maltøl contains a lot more protein and typically goes ‘off’ after a few months (though this may also have something to do with sanitation practices and the sparse use of hops). Boiling precipitates a lot of protein out of the beer and also gives opportunity to boil hops.

Recipe. My recipe was as follows for a 10 gallon batch:

Grain:
20lbs Great Western Superior Pilsen Malt
4lbs Mecca Grade Rimrock (to impress those judges)

Hops:
2oz homegrown Glacier hops in the mash
2oz homegrown Glacier hops @15 minutes

Other:
A bunch of fresh cut Leyland Cypress boughs in the strike and sparge water as well as the bottom of the mash tun. I didn’t weigh it.

Yeast:
1L starter of my wild(feral?) Abbey yeast culture, probably an underpitch…

Process:
Fill kettle with water for the strike, cut Leyland Cypress branches and stick them in a kettle and turn on the heat. Also cut boughs and lay them in the mash tun, I stuck smaller branches under the manifold in my tun. Target a mash temp of 156F, it’s also not a bad idea to actually heat the water up to boiling and then let it cool down to your strike temp to get a good cypress infusion.

Add 2oz of homegrown hops to the mash when mashing in, let it sit for one hour. While mashing add water for the sparge to your kettle along with more cypress boughs and heat that to boiling, let it cool a bit while you drain the mash of your first runnings, vorlauf if you feel like it. I’ve stopped bothering to aim for a specific mashout temp but you can target 168-170F if you want.

Drain the sparge into the same kettle with your first runnings and begin to heat the wort to boiling. Add 2 more oz of hops to the boiling wort with 15 minutes left in the boil.

When the boil is over, chill the wort, drain to fermentors and pitch yeast. I fermented at around 85F, for kveik you can push it even higher, I’ve fermented with my yeast up to 100F outside during a heat wave and had good results. 85F is about as hot as my chamber can get with its current heating elements. After about a month of fermentation I cold crashed the beer for a month or so before getting around to bottling because the competition I brewed it for got postponed.

I bottled with a low level of carbonation, around 2.0 volumes. Typically Maltøl is minimally carbed or even served completely still.

Yes it is possible to dry yeast at home. No it’s probably not going to be completely sanitary, but if you read this blog at all, you know that’s not a super high priority around here. Anyway, how is this accomplished? It’s actually quite simple. Many of the traditional Norwegian farmhouse brewers have dried their yeast for ages, the method I’m about to outline I gleaned from them with the help of Lars Garshol’s excellent blog.

What you’ll need:

• Parchment paper
• A baking sheet (not strictly necessary)
• a couple of clothes pins or chip clips
• A large spoon with smallish holes in it, a wire strainer would also probably work
• Actively fermenting beer (preferably with a top-cropping yeast culture)
• An electric fan

How to do it:

Start by clipping some parchment paper to your baking sheet

Next open your ferment at high krausen and scoop krausen out onto the parchment paper using a sanitized spoon.

Use the spoon to spread the krausen out into a thin layer so that it will be able to dry quickly. Place the pan in front of your fan blowing air across it on a low setting to help it dry faster.
 

After a day it should be fully dry and ready to collect. Crinkle up the parchment paper to get they dried yeast to flake off.
 

Dump the yeast into a clean dry jar. Label and date the jar and store it in the fridge or somewhere cool and out of sunlight.
 

Pretty simple and easy. My main barrier to doing this all the time is that fact that I generally ferment in glass carboys so I can’t get in there to scoop krausen. I have dried bottom cropped yeast slurry before and it does work, just make sure you are spreading it THIN, if it takes too long to dry you’ll end up with mold growing on it and nobody wants that. Like I said this is obviously not aseptically sanitary, certainly random wild yeast or bacteria in the air could land on your drying yeast and infect it. The drying process should help though as not all microbes handle drying all that well. If you do this to a wild culture you can certainly alter it, especially if you’re harvesting krausen, doing this over and over through a few generations you’ll definitely select in favor of the microbes that get going quickly and reduce the amount (or possibly eliminate) the slower acting microbes. Obviously this doesn’t apply when harvesting slurry post fermentation. With top and bottom cropping you’ll still be eliminating any microbes that can’t handle drying. This may eliminate brettanomyces from a culture as I have heard that yeast sellers have had difficulty drying brett to sell.

About a year or so ago I came across this video from Sui Generis about where wild Saccharomyces cerevisiae can be found:

I personally have a hard time believing the first part of the video about yeast being extremely rarely found on fruit simply due to the amount of successful yeast captures I have done from fruit. Though maybe many of these are not S. cerevisiae? Anyway, the part that interested me was finding wild S. cerevisiae on leaf litter on the ground. It makes sense since yeast can’t really fly, air can blow it around but it probably mostly just lands on the ground (vs on fruit hanging up in trees (defying my earlier assertion that fruit does indeed contain yeast)) and takes advantage of any available food or sugar it happens to come across, probably relying on other microbes to break larger carbohydrates down to the simpler sugars it is able to metabolize. I figured I’d give the idea a try.

I had been wanting to do a wild capture from an area of a nearby hiking trail where that had formerly been a brewery back in the 1880s. There’s some interesting history around this brewery. It was operated by a man named John Nagar in the town of Camas, WA. A year or two after he’d opened his brewery the town voted in their own city-wide version of prohibition (ahead of the nationwide constitutional amendment version). Nagar fought against this local law, even going so far as to put a whiskey scow out into the Columbia River with a bar on it to skirt the ordinance. Of course he was eventually defeated, and his brewery closed.

Fast forward to present day and there is a hiking trail along a creek that passes right by the former location of the brewery, there aren’t any obvious signs that any buildings used to be there but it has been over 100 years. I went down to the area where I’m guessing it was located based on an old map of the city and a spot along the trail where there is easy access to the creek and a spot that looks like it might possibly have been an old foundation, a bit of a somewhat rectangular looking cut into the side of a hill.

I gathered rotting leaf samples from four spots around this area and took them home. I prepared some 1.030 hopped wort for starters and since I was dealing with rotting leaves, I fortified the starters with vodka to bring them to ~2.5% abv and purged the headspace of the flasks with CO2 as well as I could just to protect against the plethora of undesirable microbes (mold, botulinum, etc) that are probably contributing to the leaf rot.

After about 5 days I began to see activity in the starters indicating some fermentation was probably taking place. One of the three grew what looked sorta like a glob of snot on the surface, maybe the beginnings of a kombucha type pellicle? The other three seemed normal, one had a bit of a ‘normal’ pellicle. After a couple of months I filtered all of the leaf particulates out and stepped up each of the captures. Three of the four took off, the one that grew the snot didn’t take off as much and I abandoned it at that point. The other three fermented out completely and dropped incredibly clear. They all tasted extremely similar (not too surprising), they were actually quite neutral, very mildly phenolic and minor ester production, but nothing compared to most of my other wild captures.

I split the three cultures among some saison wort for a real test. All three came out tasting pretty much the same (no big surprise), fairly clean, mild phenolic spice, not especially notable. Don’t get me wrong, they made good beer. Just the amount of yeast expression was muted. For a lot of brewing history including today this is a desirable trait. But of course I’m a weirdo and I like crazy yeast flavors. That said, these yeast certain could have a place in my repertoire for making hop or malt forward beers.

In the end, while the yeast itself isn’t especially exciting, the fact that it originated from some rotting leaves I picked up off the forest floor in the middle of December is pretty cool.

I harvested the leaf litter in December of 2017, I should have posted about this a lot sooner than now, but I’m lazy. Opening a bottle now, the beer is tasting like a nice biere de garde.

The appearance is light amber with a white head that lasts; clarity is pretty great (not unexpected after about 6 months in the bottle).

The aroma is malty, almost lagery?

Taste is malty with a hint of biscuit and caramel. Maybe a minor phenol in the background, but I might just be putting it there because I think it should be there…

Overall, this beer is pretty delicious, a nice malty beer, especially on a cold, nearly winter day like today.

One last thing to note on this post and then I’ll be done. I pitched this culture into a sort of Baltic Porter that I brewed last weekend and it is fermenting away just fine at 56F in my garage. Maybe it really is a descendant of a lager yeast from Nagar’s brewery?

or why it’s important to do multiple captures from one source

Last July I went cherry picking with my family in Hood River, OR. We picked a lot of cherries. Since some of the cherry picking help was from my 5 year old daughter, a few of the cherries we ended up with were slightly less than desirable for eating. I took it as an opportunity for an experiment. I cooked up some hopped starter wort and split it into two flasks. Then I took a few cherries that looked good enough for eating and added them to one starter and took a few cherries that had already begun to show signs of rot and added them to the other starter. Otherwise all of the cherries were from the same orchard so in theory you’d expect any microbes on the cherries to be the same/similar. I labeled the starters as 🙂 for the good looking cherries and 🙁 for the rotten ones.

Not unexpectedly, the 🙁 starter produced a krausen about a day sooner than the 🙂 starter did. The 🙁 starter also grew a bit of mold on one of the floating cherries before the krausen formed and completely overwhelmed it. I let them finish completely and then sit at room temp for a while before crashing, decanting and adding to new wort. Both starters smelled and tasted okay so I deemed them worthy of fermenting some real beer for consumption.

I brewed up a saison-like beer and split some wort between the two yeasts, I let them both ferment until I was fairly confident in the final gravity and then bottled them. Unfortunately something went sideways with the hops (I think oxidation from being lazy about revacuum sealing the bag of hops in the freezer?) and the bitterness on this beer was pretty harsh and somewhat overpowering. Regardless I still took some tasting notes but decided that I’d have to rebrew and try them both again before making a final judgement.

Here are my notes from the first tasting:

🙁 Culture

bubblegum/clove in the nose
slight clove and fruit in the taste with a harsh bitterness in the finish
more clove and some banana comes out as the beer warms

🙂 Culture

smells slightly of chlorine? or metallic?
kind of feety in the flavor
bitter finish, not quite a s harsh as 🙁
more foot aroma as it warms

So a pretty stark difference even in a batch with a pretty big flaw (that didn’t come from the yeast).

The second brew turned out well and I was able to taste the flavors of the yeast a bit better. I let this batch ferment for much longer (3-4 months) as I got busy with other stuff. Over this period the 🙂 batch formed a pretty funky pellicle while the 🙁 batch remained clear with a few persistent yeast rafts. This batch did not have a bitterness issue as I used a different bag of hops.

Here are my noses from tasting this second batch:

🙁 Culture

Aroma: Mild funk, cut hay?
Flavor: barnyard, mild spice, dry, malt hiding in the background and a soft smooth bitterness on the finish
Mouthfeel: well rounded from the carbonation
Clove and some stone fruit comes out as it warms

🙂 Culture

Aroma: sweet mousiness
Flavor: strong mousiness dominates throughout, some sort of phenol in the background? hard to tell with all the THP; slight tart fruitiness in the finish

So it seems the foot aroma went away and was replaced by a mouse. Even though THP flavors are supposed to fade with time, they can last up to a year, and the THP seems to have increased since bottle conditioning the beer so I’m not sure what’s up with that. After this batch I have decided to toss the 🙂 culture and only continue with the 🙁 culture.

It is amazing the stark differences between the two considering they both came from the same orchard. Also, one would expect to get weirder, funkier, nastier flavors out of the cherries that were already rotting but was not the case here. What conclusions can we really draw from this single point of data? Not much other than if you’re looking to catch a good wild culture from fruit, it’s a good idea to make a number of starters with your source material so that you have more chances to get a good culture.

Appearance: very pale straw and crystal clear with a big rocky head that is quite slow to dissolve.

Aroma: a bit of barnyard funk, slight malt/hops.

Taste: light beer flavor with an overtone of Brett funk throughout. For such a low abv beer there’s still a nice touch of maltiness and pretty strong funk considering. Hint of clove in the background.

Mouthfeel: fairly light, but not quite watery. Maybe a little watery.

Overall impression: As a super session saision, an attempt to make a hydrating beer for feeding to summer farm workers this definitely succeeds. This is actually my favorite variation of them. It seems like with so little malt sugar it’s difficult for sacc yeast to produce a lot of it’s signature flavors. Brett doesn’t seem to have that problem though it seems like bottle conditioning helped it out. I think I will make this beer again next spring in larger quantity if possible.

I realize I should have posted sooner about the wasp yeast. Here’s a picture:

WTF? yeah, I went and did that. It wasn’t completely my fault though. Maybe partially my fault. Okay, story time:

Ever since I captured some wild yeast from unpasteurized honey, I’ve had this thought in the back of my brain to somehow catch a bee and just throw the bee into a starter and see what I get. Well years have gone by and I haven’t done that. Then, one day a few months ago, I read an article that was posted on Milk the Funk about how some scientists determined that wild saccharomyces yeast will overwinter in the stomachs of queen wasps and hybridize in her gut. That’s kinda neat, kinda creepy too I guess.

A few hours after reading this information I was out putting some chicken into my smoker for the first time since last fall. I take the cover off, and what do I see curled up in the recess of the smoker door handle? It’s a wasp. I poked it with my finger to see if it was dead, it moved a bit, not dead, but pretty sleepy probably since it’s still somewhat cold. It’s an overwintering queen. I put her into a jar.

Coincidentally, I just happened to have to make some starters that same day for a brew day coming up. I took it as a sign from God; the wasp went into a starter. Of course by the time I was ready to put her into the starter, I had brought the jar into the house and she had warmed up and woken up and probably wasn’t too pleased about her imprisonment. Okay, so how do you get an angry wasp in a jar into an erlenmeyer flask full of wort? I thought I could put her in the freezer, but that’d take a while. In the end I just shook the heck out of the jar until she seemed to be pretty stunned then I used the flamed end of an xacto blade handle to crush her a bit and into the starter she went.

She was pretty slow to ferment initially, this picture is actually from before the starter krausened, so something else was going on in there. lacto? enteric? when I tasted the starter (before pitching it into my Farm Hand’s Ale) I didn’t detect any off flavors, mostly it was pretty bitter from hopping the starter, and had the characteristic fruity bubblegum flavors that other local captures of yeast around my neighborhood have. We’ll see how it goes. I made a lot of that beer so I can afford to let her portion age for a while to see what (if anything) shows up.

So, as you can probably guess, I love Saisons. The typical story told about the style is that it emerged from farmhouse brewing traditions in France where they needed a beer for their seasonal farm workers to keep hydrated while working. If you know anything about saison today you’ll know that it’s not exactly something that you’d want to drink a lot of and then go try to wield a scythe and get some work done. So it’s likely that the first saisons were much lower strength beers than what is typically available today. The BJCP has mentioned “Table Saison” as a variant of their 2015 definition for the style that ranges 3.5%-5% I actually wanted to make something that was even lower alcohol than that (if possible, I have this curse about trying to make session beers and they end up being 6-7% somehow). My goal was to make a beer that was around 2.5% abv, but hopefully didn’t taste too watered down.

Farm Hand’s Ale (15 gallon batch, 30 minute boil)

• 10lbs Northwest Pale Ale Malt
• 2lbs Flaked Oats
• 1.5lbs Aromatic Malt
• 1.5lbs Munich Malt
• 2.5oz Glacier Hops 3.2%AA FWH @30 minutes
• 2oz Glacier Hops 3.2%AA @2 minutes

I decided to go with the high % (though maybe not a terribly high amount) of aromatic malt for this to help give it a good malty flavor despite the small amount of malt being used. I included the oats to boost the mouthfeel of what is likely to be a rather thin beer otherwise. I used glacier hops because glacier hops are the best, and did a 30 minute boil because I like to shorten my brew day.

I mashed this beer rather thin since my HLT is my old 10 gallon boil kettle and I wanted to get 15 gallons of runnings so I mashed in with 9 gallons of water to achieve a mash temp of 155F and then sparged with another 9 gallons of water after about an hour. It took a while to get to a boil and my 19 gallon kettle was pretty much maxed out, I actually saved a few gallons off and added them to the kettle as I went to chill. Otherwise the boil went fine with no major hiccups.

I split the wort among 4 fermentors, 2 2.5 gallon and 2 5 gallon batches were all pitched with different yeasts. The 2.5 gallon batches got my wasp yeast for it’s inaugural batch and the other 2.5 gallon got some of my local yeast, that was harvested from a plum blossom. I think I need to just come up with a name for all of the local yeast captures, since they are all pretty much the same yeast. The 5 gallon batches got my hefe/brett (probably needs a better name) culture and my abbey culture that had been revived from a jar of yeast that has been in my fridge now for 3 years and 4 months, ha!

The original gravity came out to 1.031, which is 6 points higher than I was shooting for meaning my efficiency was 88.5% which seems incredibly high to me, I wonder if the thinner mash had something to do with that? So I guess this could possibly qualify at the low end a Table Saison depending on attenuation. All of the batches took off fermenting pretty quickly. I will post tasting notes when they are ready.

On March 5th I gave a presentation at the PNWHC about how to catch wild yeast. It went pretty well and I got a friend from my homebrew club to film it for me. So now it’s up on youtube for your viewing pleasure:

I’m also going to write out some words here describing what I talked about in the video for you people who hate watching videos like I do.

What is Wild Yeast

A lot of beers are marketed as wild if they contain brett, brett itself is often called a wild yeast, and WPL644 trois was thought to be brett but is apparently sacc and is being called a ‘wild’ saccharomyces. But if you buy a pure strain of brett from a lab, is it really wild? You know what you’re buying, you know basically how it will behave and what it will do to your beer. Maybe that yeast strain was wild once but I don’t really think that’s wild anymore.

My definition: Wild yeast is yeast that came from the wild

Sources of Wild Yeast

My favorite source of wild yeast is from fruit. As we all know yeast likes sugar and fruit generally is sugary so fruit would be a logical place to expect to find yeast in larger proportions. Some fruits I’ve gotten yeast off of: dates, juniper berries, cherries, grapes, apples. Other good options to try: raspberries, blackberries, blueberries, plums. Farm pressed unpasteurized apple juice is another good source, just get the juice, stick an airlock on it and let it ferment.

If you’re trying to capture a sort of terroir for a specific area then I recommend using fruits harvested from that area, either grown yourself or wild foraged. You can also get yeast off of store bought fruit, just try to get organic if you can and do not use irradiated fruit as that won’t work.

Veggies are another good source, though you’re more likely to find bacteria on vegetables. Think about sauerkraut, you chop up a cabbage, mix in some salt and it ferments itself; plenty of lacto there. Ginger root and it’s cousins (turmeric, galangal) seem to have a plethora of useful microbes hanging out on them including sacc, brett, lacto, even some useful molds.

Flowers are another option for wild yeast, especially if it’s spring and there’s not any local fruit in season to harvest from. I recommend using edible flowers, like apple/plum/cherry/peach blossoms, roses are also edible.

Raw/unpasteurized honey is another good source of wild yeast. Isn’t honey anti-microbial? It kind of is, but the main reason it never goes bad is that same reason that a sack of sugar in your cupboard never goes bad, the high concentration of sugar is the main thing that protects it. the sugar sucks the moisture out of any microbes that happen to be in there, causing them to go dormant or die. But the ones that don’t die are dormant just waiting for the conditions to become favorable, ie the sugar gets watered down.

Insects are another source of wild yeast. I recently read about how Saccharomyces overwinters in the stomach of queen wasps, a few hours later I just happened to find one taking a nap on my smoker, I also had to make starters for a brew that evening so I took it as a sign from God. She went into a starter as well, fermented quite vigorously too. I haven’t used her in a beer yet.

Open air inoculation is probably a method you’ve heard of for producing wild yeast beers. Lambic and other belgian sour beer producers utilize this method most famously and some american breweries have also begun replicating this process. I haven’t done a ton of open air inoculations, from what I’ve read of other people doing it, it’s a good way to catch mold, though I have been successful the one time I’ve tried it.

How to capture

So you’ve got your source, how do you get the yeast that may be on it into a beer? Essentially it boils down to: make a starter, add your source. However there’s a few things to do a bit differently for this starter:

if you’re just trying to capture yeast and not bacteria (yeast in this case includes sacc and brett) you should make a hopped starter, just toss a small amount of pellets in your starter before you boil it, you don’t have to target a specific IBU level hops will inhibit lacto even when dry hopped. Make sure your starter is high enough gravity (~1.030) to end up being above 2% abv when fully fermented out, this will kill enteric bacteria. I also add some nutrient to the starters to give the yeast some extra food. Shake up or otherwise oxygenate the starter before adding your source.

Add the source. If you’re inoculating from open air, I’d pour the starter into a sanitized shallow bowl, cover with cheesecloth to keep bugs out (or don’t) and let it sit out for at least 3-4 hours and not longer than 24 hours, shorter is probably better to minimize oxygen exposure and reduce the chances of catching mold. Then add it back to your starter flask. Put an airlock on the starter and don’t stir or otherwise try to aerate this starter at this point. This is to deter mold and acetic bacteria.

Wait patiently. I’ve had to wait upwards of a week before I noticed any visible activity/fermentation in some starters.

If you want to catch both yeast and bacteria then there are a few things to do differently. Mainly, don’t hop the starter. Add your source and cap the starter with foil and feel free to aerate. Try to keep the starter cool, in the low 60sF if you can, this helps the yeast to have a chance to grow alongside the faster growing bacteria which prefer warmer temps. Again, wait patiently.

Safety Considerations

Some nasty things can potentially grow in this first starter that can make you ill. You’ve probably heard that no human pathogens can grow in beer and this is generally true, but they can grow in wort. The reason why this isn’t an issue for homebrewers is that they are typically pitching a vast amount of yeast into their wort and nothing else is going to have a chance. With this first starter, we’re not pitching a vast amount of yeast, we’re pitching a tiny amount of yeast, and also a tiny amount of other microbes that we may not want.

Here are some things to do to lower the risk of those things taking hold.

Pre-lower the pH of the starter wort to 4.5 or less to inhibit E. coli and C. botulinum. Typical wort pH is 5.0 so you don’t have too far to go to get to 4.5. You can also fortify the wort to 4+% abv by adding a neutral spirit such as vodka, this will inhibit E. coli and outright kill enteric bacteria. You can also keep the starter for a month at room temp (not in the fridge) which will let E. coli really die off. You can read more about safety precautions here. I haven’t done any of these things (partly because I wasn’t aware of them until recently) and I haven’t gotten sick, maybe I’m just lucky? Regardless, if you do happen to be immune compromised then I recommend that you stick with lab yeast.

Did you catch anything good?

So now you’ve got your source in your starter, how do you know if you caught anything good? Well first off, did it ferment? Like I said earlier, be patient, you may have to wait some time to see any signs of fermentation and it’s also possible (but unlikely in my experience) that it may not ever ferment. If it doesn’t ferment then, obviously you didn’t catch anything you’d likely want to put into a beer. If it does ferment, let it ferment out completely.

Did it grow mold? If so you should toss it and start over. Yes there are some molds that aren’t harmful, but I don’t know how to distinguish them from the bad ones so better/safer to just start over.

If it fermented, how does it smell? If it smells awful, like poo or vomit or feet, you probably don’t want that in your beer so chuck it and start over. If it smells good, that’s a good sign that you got something good. If it smells good and didn’t grow mold crash it in the fridge, decant the pseudo beer from the top of the yeast and give that a (small at first) taste. It’s not going to taste exactly like beer but it’ll give you an idea. If it tastes good then you probably got something good.

You probably noticed I said toss it and start over a number of times above, while my success rate for catching wild yeast is above 50% there are many roads to failure at this step so you may want to make up multiple starters at one time to increase your chances of success.

Step it up

Now that you’ve caught something good it’s time to step it up to eventually pitch into a large batch. You can do a starter now how you normally would, though if you’re going for just yeast it won’t hurt to continue using a few hop pellets in your starters. Feel free to aerate your starter like your normally would at this point.

Make beer!

For newly caught yeasts I typically have a standard saison recipe that I like to pitch it into, but you can let your culture choose the style of beer you brew, if it seems very fruity, maybe a british or american style would be more appropriate. Spicy/bretty would lend itself to a saison or farmhouse beer. bubblegum and clove flavors could do well in a wit or abbey style beer. Did you go for bacteria and get some sourness? Brew a Berliner Weisse or Gose. Whatever you choose to brew for this initial large batch of beer, I’d steer away from overly hoppy or malty styles just so that you can really get a good understanding of the sort of flavors your yeast produces.

Keep in mind that your wild yeast may take longer to ferment a beer. I typically give my beers at least two weeks in primary sometimes as long as a month depending how busy/lazy I am. For the first trial of a new yeast, when it seems to be done fermenting ie the beer has reached expected FG (or lower) and doesn’t seem to be dropping any further, I like to rack a gallon into a separate jug, put it under airlock and stash that away for 6+ months just to see if the yeast does anything further with the beer. Sometimes after tasting that aged beer I’ve wished that I had left the entire batch to age. The rest of the beer I’ll keg, I recommend against bottling, especially for this first batch just because you don’t know if they yeast will slowly continue to produce CO2 and result in bottle bombs. If you are unable to keg then you could bottle and store the bottles in the fridge after they have primed, but I still caution against that as I’ve had some jars of slurry carbonate in the fridge. Cold temps aren’t a guarantee of stopping some wild yeasts, they can be very hardy.

Save the slurry

After racking the beer off the trub, I just dump it all into a jar and stick it in the fridge. Put a label on the jar or you will forget what it is. I have 2 mystery jars in my fridge right now. When I want to make a beer with that yeast again, I’ll make up a starter and just take a scoop of the trub from the jar and grow it up in the starter. In this way I always have a sort of baseline from which to draw, every beer with that yeast is ‘second’ generation. How long can you store it? I’ve had one jar in the fridge for three years and still got viable yeast out of it, though it took a lot longer for the starter to get going. Maybe it’s just that particular yeast, but like I said wild yeast is typically hardier than their coddled lab cousins.

Where to go from here?

Well obviously, make amazing beer. If you want to get more scientific you can learn about making plates for isolating specific yeast strains from your culture and making slants for better long term storage. I haven’t done either of these things yet. As we know with homebrewing, the rabbit hole goes ever deeper and you can go as deep as you want.

More resources

Here are some more great resources for info about wild yeast beer, sour and funky and other crazy beer experiments.

You’re probably already familiar with The Mad Fermentationist. If not it’s a great blog about wild and mixed microbe beer making (among other things). he has also written a book called American Sour Beers that I can’t recommend highly enough.

There is a facebook group called Milk the Funk that is just amazing. It’s full of tons of smart people who are happy to share their knowledge and are doing a ton or really interesting things with beer. Joining that group has vastly improved my facebook feed. Milk the Funk also has a website with a great wiki full of tons of great info.

The Yeast book by Chris White and Jamil Zainasheff is also a great resource though it can get pretty technical at times. It is packed full of great info about yeast in general.

Another great resource is Wild Brews by Jeff Sparrow, this book deals more with the production of Lambic and sour Flemish ales. There’s a ton of great info about a lot of the microbes we’re looking to catch though: Saccharomyces, Brettanomyces, Lactobacillus, and Pediococcus.

I hope this info is helpful to you. If you have any questions hit me up on twitter. Go catch some yeast!

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Update: A Spanish homebrewing blogger requested to translate this post into spanish for his readers: here’s the post!

Update: A French homebrew blogger has translated this post into French.

Appearance: Fairly clear light straw color with minimal head that dissipates quickly into a thin surface lacing. Vastly different from the other raw beers.

Aroma: Slightly hoppy with a rustic barnyard note: earthy, herbal.

Taste: Grainy, herbal, a touch of citrus/lemon, funk throughout. I love it. The taste is everything I want out of a farmhouse ale.

Mouthfeel: Fairly thin but not watery; hard to explain.

Overall impression: This is a great beer; like I said above, it’s everything I want a farmhouse ale to be. I’m really pleased with this, especially since I was initially considering dumping it. This was the other half of the batch with the cypress/lemon balm wort, fermented with a wild sacc/brett mix for four months. It had this sort of unpleasant dirt flavor going on that I really disliked, I think from the lemon balm? I figured I should try dry hopping it so I filled a bottle from the fermenter, dropped a couple of horizon pellets in and a carb tab, after a week it was pretty good. I tried it again with some glacier pellets and it was also good so I kegged it with both and I was blown away! The dirt flavor is gone and replaced by this pleasant citrus note. Additionally the hops just seem to accentuate the funk from the brett. I need to dry hop with these hops more, they really are my favorite varietals.

Another thing rather striking is the clarity of the beer. Considering the other raw ales were quite hazy this one is downright transparent. I don’t know if that’s from the time or the brett or both.

Appearance: The beer is a pale amberish to slightly red in color, with a respectable amount of head upon pouring that condenses into a mat of foam capping the beverage.

Aroma: A hint of roast (I assume from the victory malt) and subtle esters.

Taste: Malt and mild roast with maybe a bit of hoppy astringency. I think I don’t like the Sonnet Hops that I tried out for this beer. There are some subtle esters below the surface but nothing that really stands out.

Mouthfeel: Thin with high carbonation on the tongue. I may have bottled this too early.

Overall Impression: I don’t really like this beer all that much. Not that it isn’t a good beer, it is. There aren’t any off flavors that I can detect, I think it’s just the matter of I don’t like the Sonnet Hops. That said, I prefer the control I fermented with the same yeast (the one that came from my neighbor’s honey) that hadn’t been dried on a stick. The control seems to have more fruity esters and bubblegum flavor that I really like about this yeast. Now that I think about it, the kveikstokk yeast is a bit more similar to other wild yeasts I’ve captured from around the area here.