Yeast Nap or Dirt Nap?

[EvilOtto]

Just a quick one for the forum. I pitched yeast into my most recent batch of Porter. The temp was a bit higher than normal (27 C), but it took off like a monster. By 8 AM, pressure through my airlock was boring my carboy down towards the center of the earth. I looked at my temp and it was off the scale (high-end is 30 C) and I was worried that I might be pushing it a bit more than I wanted to, so I chucked it in my regulated chest freezer set at 24C. After about 2 hours, fermentation started slowing down significantly so I checked on the temp (it was about 25C), so I pulled it and stuck it back in my fermentation cubby hole. Within an hour, the fermentation that was going like gangbusters just stopped. I re-pitched, and it didn't take off again. I checked gravity and I've only gone from 1.060 to 1.040. I'm expecting something around 1.016, but I'm stalled....

A) Any thoughts on why a couple of degree drop over a couple of hours would so drastically affect my fermentation?

B) Any thoughts on what to do?

Hugs!

Otto

 

[RM-MN]

1. Did you check the gravity with a refractometer or a hydrometer?
2. How long since you pitched the yeast?
3. What yeast did you use?
4. What was the recipe you used?

 

[lbcsax]

To my mind that is a very large temperature swing for the yeast to undergo in a few hours. They got the signal to go dormant. I've heard you can lower the temp a degree F an hour or so.

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[peterj]

All of the temps you said are WAY too high for most yeast strains. At temps that high yeast produce a lot of weird esters and harsh fusel alcohols. Most yeasts should be kept in the range of 16C to 21C. Each specific yeast will give you a temp range and I generally stay in the middle to low end of that.

I'm interested to know if you checked it with a refractometer as well (those aren't accurate once fermentation begins) because at such a high temp and with so much activity it sounds like your fermentation should be done.

 

[EvilOtto]

I did use a refractrometer. I'll do a hydrometer reading today. The yeast was Windsor. I can't believe it was finished. It was a little bit over 1 day. Even if the initial pitch went dormant, why would the repitch take off?

 

[EvilOtto]

The grain bill was Pale, chocolate and black patent.

 

[BigFloyd]

All of the temps you said are WAY too high for most yeast strains. At temps that high yeast produce a lot of weird esters and harsh fusel alcohols. Most yeasts should be kept in the range of 16C to 21C. Each specific yeast will give you a temp range and I generally stay in the middle to low end of that.

+1. Bad news. Your ferment temps are off the chart for Windsor (or any other non-saison ale yeast for that matter). Pitching and fermenting that hot is a sure-fire recipe for some serious nastiness. I'd not wish to drink that beer nor suffer the headache those fusels will cause.

I'm confused. If you have a regulated chest freezer, why did you not use it to chill the wort to 16*C before pitching and then set it to 18-19*C to ferment?