Author Topic: Isolating Wild Yeast  (Read 764 times)

Offline Shoe

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Isolating Wild Yeast
« on: July 12, 2017, 01:20:47 AM »
Good day!
     I recently isolated (I think) two separate strains of yeast from some oak bark.  One is fermenting nicely, albeit slowly, and the other has me perplexed.  I isolated the strains and put each in a wide-mouth canning jar with an airlock.  The strain that has me perplexed appeared to ferment normally (the airlock suggested CO2 was being released) and then it appeared to reverse and started to suck the sanitizer I had in the airlock into the jar.  I think this yeast is a brett based on the pellicle http://www.iamtheshoe.com/gravity%20test4%2026%20june.jpg it formed and it had a strong apple smell.  I've never heard of air being sucked into a fermenter.  The only thing I can think of is that after using the oxygen in the head space of the jar it "gasped" for oxygen and sucked the sanitizer in to the point that air flowed freely into the fermenter.  You can see the bubbles trying to go inside the airlock tube http://www.iamtheshoe.com/Sucking%20Fermenter.jpg.  Has anyone seen this before or can anyone offer an explanation?

Offline Stevie

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Re: Isolating Wild Yeast
« Reply #1 on: July 12, 2017, 02:17:16 AM »
Your links are broken. If you have a lot of headspace, decreases in temperature can cause air to be sucked in.

Offline Shoe

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Re: Isolating Wild Yeast
« Reply #2 on: July 12, 2017, 03:12:24 AM »
I've had it a the same temperature throughout.  Not sure what's up with links...they work for me.

Offline Stevie

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Isolating Wild Yeast
« Reply #3 on: July 12, 2017, 03:33:20 AM »
Small changes in temperature can cause the headspace to become more dense and suck in. This happens with my 7.5 gallon fermenters with 5.5 gallons of beer. If the fermentation hasn't kicked off or is slowing down, not enough gas is getting kicked out to counter it. This happens when the temp is off by as little as half a degree F.
« Last Edit: July 12, 2017, 03:35:33 AM by Stevie »

Offline Bob357

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Re: Isolating Wild Yeast
« Reply #4 on: July 12, 2017, 09:31:38 AM »
When active fermentation is complete a drop in temperature is normal. The temperature drop will cause negative pressure in the fermentation vessel. This is a good time to use an "S" type airlock. The "S" type allows gas exchange in either direction without liquid passage. Using sanitizer or spirits in the airlock will minimize the possibility of contamination from incoming air.
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Offline Stevie

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Re: Isolating Wild Yeast
« Reply #5 on: July 12, 2017, 01:48:42 PM »
When active fermentation is complete a drop in temperature is normal. The temperature drop will cause negative pressure in the fermentation vessel. This is a good time to use an "S" type airlock. The "S" type allows gas exchange in either direction without liquid passage. Using sanitizer or spirits in the airlock will minimize the possibility of contamination from incoming air.
Properly filled 3-piece airlocks will allow air to flow back as well. Maybe some liquid, but minimal.

Offline reverseapachemaster

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Re: Isolating Wild Yeast
« Reply #6 on: July 12, 2017, 04:48:39 PM »
Agree with the above posts about the airlock situation.

Don't assume based on a visual observation of a pellicle that you can determine anything about the yeast, bacteria, or assembly of microorganisms in a culture. Plenty of wild yeast (even among the saccharomyces genus) and bacteria create pellicles. Many other wild yeast produce similar flavors and attenuation as brett. The only way to know for sure would be to look under a microscope with the proper dye.

That said, not knowing what it is does not mean you cannot brew with it or produce something you enjoy.
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Offline Shoe

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Re: Isolating Wild Yeast
« Reply #7 on: July 13, 2017, 02:29:42 AM »
Good stuff...thanks.  Yes, I probably need to invest a bit more in my yeast project with a microscope.  So by this point I probably have 50ml of sanitizer in the 300ml sample...will this harm the yeast (or whatever I might be growing)?