View Full Version : Heat stability

03-10-2005, 06:36 PM
I was involved in a discussion over the last couple of days with a friend that makes hard cider. One of the topics was heat stability...

We ran into it first hand in the hard cider yeast tests (which I am slowly posting in the Brewlog section) with one batch in particular that clouded up (it did not start fermenting again) when I brought it from the wine cellar (45F) to the dining room (70F). So a few questions for the experts...

What causes it? I could understand if a renewed fermentation caused debris to go back into suspension, but this wasn't bubbling...

What cures it? Pectin? Benzonite? Other things?

Thanks in advance,

03-11-2005, 12:50 AM
Most Probably started back up even though no bubbles yet. Yeasts are multiplying under warmer temperatures.. Leave it in warmer temperatures and it probably will bubble shortly.

03-11-2005, 07:26 PM
How long did you give it in the carboy before you bottled it? With my first, I made the mistake of bottling too early. It continued to ferment in the bottle and although it didn't explode, it did produce sediment.

If you had much sediment in the bottle either from bottling too early, or not racking correctly, it would solidify while it ages and the mead would clear. But if it's still in there, then when you pick it up, pour etc it will shake it up and the sediment will become loose again.

03-12-2005, 03:16 AM

I racked it off the yeast at the end of fermentation and then it set for two weeks in a room at 45F. All but one of the batches were sparkling clear in that room. I brought it out about 30 minutes before tasting and it had already clouded up. And no, the cloudiness was not from stirring the sediment while carrying it upstairs. It was still nice and clear when I set it on the table. Dunno...

03-12-2005, 06:59 PM
This is just a guess, but do you think that you may have just put the yeast to sleep with the cold temperature, rather than let them die off?

If you chill mead in the fridge, allow it to clear, and then rack it and leave it in room temperature, the mead will usually start up again. The cold puts yeast to sleep, it doesn't kill the yeast. That's why when people stabilize a mead, they always add sorbate and sulfite after chilling. Just chilling wouldn't work.

If the yeast in your mead is dorment at 45F, it is only natural that fermentation could start back up at 70F, since 70F is the ideal temperature for most yeasts.

I realize I'm not an expert on this. What do you think? Do you think this might be why?

03-13-2005, 12:26 AM
That is indeed the most likely senario and to be expected. Yeast go dormant at low temperature but come back alive when back in their temperature range. Its not much of a mystery.