Harvesting Wild Yeast

[nzbourbonguy]

About a week ago, I started a new experiment, trying to harvest wild yeast for a unique yeast strain for my various experiments.

To start, I created a sugar solution of 7g sugar to 100ml water and some fermaid o. I added 3 unwashed grapes and left it at room temp, with a lid covered in foil. Then, I swirled it every 6 hours for the first 3 days. By day 4, there was a healthy ferment going, the water was cloudy and bubbling on the surface.

At this point, I created a 500ml solution with 30g sugar & 1 tsp fermaid o. After that, I poured off the original starter into the new solution, removing the grapes. The starter populated again for another 24 hours.

From here, I made another 250ml sugar solution and added 30 ml of the mother starter.

After the latest batch populated overnight and was added to a 5 gal batch of apple cider. This morning, I checked on the state of things and we have an active and healthy ferment.

I'll report back with results. The mother starter is covered and in the fridge. I may set up a secondary mother to use for new ferments and save the primary as a yeast jug.

[OldRanch]

There are incredible yeast labs creating seriously unique yeast strains, and I'm not sure how much research you've done on wild yeast strains, but finding a viable, strong, competitive yeast strain that also creates decent flavors is kind of a wasted effort, hence, advanced yeast labs.

Good luck regardless, if nothing else you'll have created a decent sourdough starter.

[Salt Must Flow]

nzbourbonguy, just before I started distilling I started a pint jar with some wild berries from my property. It fermented away very quickly and was really cool to watch. I never tried that yeast because I read basically what OldRanch said and have only used Fleischmann's yeast and Lalvin EC-1118. I admit I regret not ever having tried it at least once with at least a relatively small batch. Good for you for trying it. I hope it works out great.

I've also considered a wild sourdough yeast starter, like people start for making bread. A relative offered to give me a bit of his well established batch and I declined. I sometimes wish I tried that too. Whenever I looked into it, people said that better yeasts can be purchased so that's all I've ever done. I look forward to hearing your results

[Demy]

I have experimented a few times with yeast from fruit (on apple cider and beer) but the taste was bad ... But it works well on fruit that will be distilled.

[jonnys_spirit]

I use natural yeast on wines to good effect IMO - It comes in on the grapes from the vineyard and ultimately I'll make grappa and brandy from some of that wine too. They're often not resilient enough or perhaps the grapes were treated with SO2 pads during harvest which has stunned the natural yeast. Having a commercial yeast available to start/pitch after a couple/few days of natural yeast activity is a good idea too if you want to finish dry.

Cheers,
jonny

[hellbilly007]

I've read of people mixing a batch of LME or DME and splitting it amongst several sterilized jars and placing them under apple trees for wild yeast harvests. Among those that I've read, they were pulling samples from each and swiping them among petri dishes containing agar. From which they observe under microscope, after an inoculation period. Not sure which characteristics are desirable at that level though.

Some brewers have gone to the extent of creating yeast labs in their homes. This is very interesting to me but perhaps a bit OCD

[still_stirrin]

… The mother starter is covered and in the fridge. I may set up a secondary mother to use for new ferments and save the primary as a yeast jug.

I just hope it doesn’t make you bottles of vinegar. Just because it’s bubbling doesn’t necessarily mean it’s making alcohol. Wild yeasts can be a “slippery slope”. If you’re an experienced brewer, then maybe you know how to ferment exotic flora. I’m not, so I try to eliminate the “wild stuff” and stay within the bounds of controlled fermentation.
ss

[The Baker]

Some brewers have gone to the extent of creating yeast labs in their homes. This is very interesting to me but perhaps a bit OCD

If you wanted to ferment whey or other milk products you might want to use one of the Kluyveromyces yeasts.
Maybe not easy to obtain and possibly expensive even in small quantities.

So you might want to propagate it in a home lab.

Geoff

[nzbourbonguy]

… The mother starter is covered and in the fridge. I may set up a secondary mother to use for new ferments and save the primary as a yeast jug.

I just hope it doesn’t make you bottles of vinegar. Just because it’s bubbling doesn’t necessarily mean it’s making alcohol. Wild yeasts can be a “slippery slope”. If you’re an experienced brewer, then maybe you know how to ferment exotic flora. I’m not, so I try to eliminate the “wild stuff” and stay within the bounds of controlled fermentation.
ss

I appreciate the words of both caution and encouragement.

I have ran a whole bunch of ferments over the past few years. Thankfully, the yeast starter was fermenting and left a lovely boozy smell before it went into the fridge to preserve/cold crash. Thankfully, if this experiment doesn't pan out, I still have a half kilo of Redstar Premier Classique to break into.

Frankly, I'm impressed at the healthy cider fermenting away right now. It has a really clean, fruity & floral aroma underneath the blanket of CO2. In a few more days, it should ferment out dry or close to it and I'll have a better idea of how the yeast did.

[Demy]

This is true... here where I live small growers (I mean for home use) don't use commercial yeast... the same I don't add yeast to my wine... but I did an experiment: I inoculated a little wine fermenting in a batch of beer..result was undrinkable. So I guess indigenous yeast is good or bad based on the final product…

[NormandieStill]

Last year I used a champagne yeast for making apple wine for distilling. But I had one batch of about 25L that started fermenting with a wild yeast and I just let it run. The low wines from that batch were more intensely appley than those from the champagne yeast. This year we're radically increasing the quantity of apples and letting everything run wild with a view to compensating for the lower yield but hopefully capitalising on the flavour.

[Demy]

Last year I used a champagne yeast for making apple wine for distilling. But I had one batch of about 25L that started fermenting with a wild yeast and I just let it run. The low wines from that batch were more intensely appley than those from the champagne yeast. This year we're radically increasing the quantity of apples and letting everything run wild with a view to compensating for the lower yield but hopefully capitalising on the flavour.

I had a similar experience...like I said if you distill it's fine but you have to drink it it doesn't taste good. Spontaneous fermentation has the advantage of creating a multitude of by-products which creates an aromatic complexity during the distillation phase.

[nzbourbonguy]

Giving an update on the harvested grape yeast.

The 5 gallon batch of cider fermented both dry (1.001) and incredibly clean. It maintained a lot of the apple fruity aromas and flavors. When it finished fermenting, it floculated nicely, leaving a very clean and compact lees in the fermenter.

I ran it double pot still and ended up with 1400ml hearts @65.3% ABV. The only apple brandy I've made that turned out better used a cold pressed apple juice where this batch used a super cheap 100% apple juice.

Since then, I just pitched another starter from the mother in a single malt mash. Lets see how the yeast handles grain spirits. I may need to take some barley and do the same yeast capturing if things get too funky with this yeast strain. It will be my new go-to fruit spirit yeast moving forward.

When I'm so motivated, I'll be making a large 1.75L batch of yeast to work through as a gen 2 mother.

[bilgriss]

I've had mixed results with wild yeasts, some good and some not. After a batch of cider ended up distinctly and irrevocably fecal in nature, I've more or less decided it's not worth the risk and work with predictable yeasts.

[nzbourbonguy]

I can't blame you, that seems rough!

[nzbourbonguy]

Another amazingly wild update for things.

Ive since made an apple brandy, a turbinado & panela rum, and all-grain wheated bourbon with the harvested yeast. Every one of these batches have been some of my finest distillate to date. This is in comparison to using DADY, Lalvin K1-V1116, 71B, EC-1118 (only good for sugar wash & carbonation, imo) and Red Star Premier Classique.

Additionally, I've made another Gen 2 starter with sugar & fermaid o. After letting it develop for 36 hours at room temp, I cold crashed it. Upon separation and defloculation, I decanted the majority of the liquid and portioned the rest of the liquid into 5ml portions in 10ml vials. From there, I added 5ml of a 50/50 blend of water & vegetable glycerin to each vial. After all of the vials (20 qty) were prepared, they were added to a container of pre-chilled (0°C) 91% isopropyl and placed in the freezer for 48 hours. After 48 hours, the alcohol was removed and the vials were labelled and dated for future reference.

From what Ive read in the past, a 25% glycerin solution will allow for the yeast cells to "freeze" without damaging the cell walls (well, 20-50%, higher if you perfer to pull small samples for inoculation instead). Additionally, the alcohol allows for a set cooling rate to minimize cell damage during the freezing as well.

To test viability, after 2 weeks in the freezer, I pulled a vial out and added it to a fresh starter solution and sure enough, we had a very healthy and active fermentation after 48 hours.

I think its fair to say I'm set for a good long while before I need to buy/harvest yeast again in the future.