DAve Allison wrote:
> i've been reading this thread and learning a lot. I have used both
> techniques with mixed results. one thing I do know - the must must be
> warm. I use a heating blanket on my kits that are in primary for 5-7
> days, keeping the temperatur at 75, the top end of the range the kit
> says (65-75) - and the yeast loves it. I just sit the bucket onthe
> heating pad and have a floating thermometer in the must to determine if
> i up or down the setting. It is amazing compared to room temperature of 68.
> A question, if I go up to 80, would the yeast start dying from the heat?
> hmm. I'm not experimenting but wonder. Any one know? Maybe it just would
> bubble and turn to alcohol too fast. I don't know.
> DAve
>

The yeast won't start dying from 80 F, they actually prefer it even
hotter. The problem is the fermentation goes too fast and you increase
your chance of 1) losing some of the variatel characteristics of the
grapes, 2) increasing some off flavors like higher alcohols, 3) with
red grapes, you reduce the amount of time the wine sits on the skins
which could lead to lower extraction.

I ferment with the temp in the high 50s low 60s, especially with white
wines. Reds I tend to let spike up higher.

Andy