Wild Yeast?

Thu Nov 17, 2011 1:22 pm

Two weeks ago I brewed a barleywine with an OG of 1.092 and put it into a carboy. I pitched a 2L starter of re-harvested Wyeast Scottish Ale yeast (w/ yeast nutrient and zinc) as well as a Mason jar of freshly harvested Wyeast 1056 to ensure sufficient yeast population (probably a little over board, but it's a barleywine). After fermentation had slowed (4 days), I added 1.5 lbs of can sugar and 1/2 each of dried dates and figs, which I chopped and boiled with the sugar and water for half an hour before pureeing and pouring through a sanitized funnel into the carboy. I wanted to bump up the gravity, dry the beer out a little and add a little complexity with the fruit through this process. This should have bumped my gravity up to somewhere in the range of 1.105-1.110.

Last night I took a gravity reading before adding my dry hops and it came out at 1.005 for a final gravity. This gives me almost 95% attenuation and 13-14% ABV - both things that those yeast strains should not be able to achieve (my hydrometer reading is correct - I double checked my calibration and readings right after). My thought is that I got a wild yeast, though I smelled nor tasted any off flavours in the beer (though it certainly is dry!).

As a test (and a hope to add a bit more residual sweetness) I boiled some LME and brown sugar and poured it into the carboy last night and this morning it was bubbling again slightly, which means that there is still fermentation despite the 13-14% ABV - which again makes me think wild yeast, unless I somehow created super yeast with my over pitching and mixing of strains.

Thoughts? Anyone ever seen these yeasts hit these sort of numbers or are my worst fears correct?
NorthernDarkness
 
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Re: Wild Yeast?

Fri Nov 18, 2011 8:22 am

Providing your sanitation procedures are good, it sounds like you pitched more than enough yeast to ferment out that barleywine before any wild yeast infection could probably take hold. What did you mash the barleywine at, or was it extract? What type of grains were in your recipe?
"A bad man is a good man's job, while a good man is a bad man's teacher."
brewinhard
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Re: Wild Yeast?

Fri Nov 18, 2011 1:21 pm

I think you just had a really healthy fermentation, man. I've had this happen before too where the yeast exceeded it's expected alcohol tolerance by a few percentage points. I highly doubt you have a wild yeast in there, partly because wild strains usually have a much lower alcohol tolerance but also because they take a longer time to work, and you said the beer is only a week or so old at this point. If you want to raise your final gravity, use some lactose or malto dextrin - the LME and brown sugar you added is probably going to ferment out pretty dry, unless your yeast finally dies off ;)

At this point I would say don't worry about it. Let it finish up for another week, keg it, and put it away for a few months. Then enjoy!
herbaljoe
 
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Re: Wild Yeast?

Fri Nov 18, 2011 1:30 pm

Anymore Wyeast 1728 is my preferred yeast for barleywines and other big beers because it can handle high gravities. You just had a good healthy fermentation.

Wayne
Bugeater Brewing Company
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Re: Wild Yeast?

Mon Dec 19, 2011 8:28 am

Don't forget that with that much alcohol you significantly lowered the density of beer masking residual sugars. I don't have the formulas to adjust in front of me but would guess that your real degree of attenuation would have you in the teens. With low mash temps, sugar additions, and high pitching rates your results seem about right. And I second the comment that a wild yeast or bacteria wouldn't have worked this quickly.
pohldogg
 
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