Yeast with a 2nd wind

What went wrong? Was this supposed to happen? Should I throw it out? What do I do now?

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Yeast with a 2nd wind

Postby Greg Anderson » Sun Aug 07, 2005 10:59 pm

Hi,
I had a batch cooking slowly in the carbouy for 10 days as usual. I woke up today intending to bottle the batch, but found it bubbling away like no tomorrow. This was after my usual routine - a day of vigorous fermentation in the primary bucket, then transferring to the carbouy late on day two, where it sat for 10 days with no noticable activity. This is normal for my brews.

This batch had a lot of hops in it and some orange peel, amounting to almost 2 inches of sludge at the bottom. It smelled delicious through the airlock, as usual. But it was foaming and bubbling like it had just started 12 hours earlier. Maybe there was a pocket of yeast that woke up from hibernation and started eating?

I went ahead and transferred it to a second carbouy, running it through a fine screen along the way. Specific gravity was 1.007. It looks fairly clear with just a bit of sediment. It's cranking out maybe a bubble a minute through the airlock now.

So, is it all right to have a batch get very active after a week or more of quiet aging?

:?:

--- ga
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Secondary Fermentation...

Postby Mesa Maltworks » Sat Sep 03, 2005 10:08 am

What was the gravity when you transferred from the primary to the secondary?

You noted "This batch had a lot of hops in it and some orange peel, amounting to almost 2 inches of sludge at the bottom".

If you decanted off of all of this from the primary, this would not be an issue.

You commented "I went ahead and transferred it to a second carbouy, running it through a fine screen along the way".

This is not a good idea! The passing of the fermented beer through a screen will cause a lot of oxygen uptake that will impact flavor and stability. Besides if you had decanted off all of the trub from the primary, there would only be fine particulate that settled out in the secondary, so sieving would be unecessary.

And to answer "Maybe there was a pocket of yeast that woke up from hibernation and started eating? "

This could not occur. During primary fermentation CO2 and convection serve to "stir" the whole wort... trub and all. Yeast don't swim around... they move on these currents. This is also why the notion of "top fermenting"/"Bottom Fermenting" is also a misnomer... yeast ferment throught the beer. The only reason you see lager yeast more on the bottom of fermenters is because of reduced temperatures which results in less convection and, due to slower metabolic activity, slower CO2 release. If you doubt this, ferment with a lager yeast at ale temperatures... the fermentation will look similar to that of an ale yeast.

"So, is it all right to have a batch get very active after a week or more of quiet aging? "

It is not normal, but it is hard to say what effects this will have on the final product. It does suggest that there were either/or/and: wort nutrition, yeast viability/vitality or pitching rate issues. This is assuming that you had a sanitary wort. There is always the possibility that what occured was the evolution of a bacterial ferment. I can't rule this out, particularly since your gravity now sits at 1.007. That is pretty low and you mentioned that the airlock was still bubbling. You can easily test for this one... check the pH of the beer. If it is below 4, you most likely have beasts producing lactic or acetic acid at work. :(
Make your next beer (or spirit) a local one!!!!

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Seven Fathoms Rum
Georgetown, Grand Cayman
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