Hot or Cold fermentation?

I'm doing a Welch's recipe based on Yooper's and using Welch's frozen Niagara concentrate and K1-V1116 yeast. I've had conflicting advice over keeping the fermentation area cool or warm. A friend who makes white wine from grapes insists that I should keep my carboy in a cool water bath and maybe even use a towel to wick water and a fan. He feels whites are best fermented very cool, and that they maintain subtle aromas much better that way.

However, I read online that wine kits, even whites, are best fermented on the upper end of the range, maybe 75F or so. This is necessary because kit juice is concentrated and sterilized, so it need a "hot" ferment to "unlock" the flavors and aromas.

Well, Welch's frozen juice is neither a wine kit nor raw grapes. It does seem closer to kit juice though because it is concentrated and probably pasteurized too.

So should I use a cold bath, a heating pad or just let it ferment at my variable room temps?

nah just let it rip dont worry about cold baths and what not, as long as you stay within working temp of your yeast you should be fine.

According to the Lalvin website, that yeast works between 10 and 35 degrees Celsius (50-95 Farenheit), so as long as you're in that range, it will be fine.

Won't the must go bad it the temps are in the 90's?

Sammyk said:

Won't the must go bad it the temps are in the 90's?

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Go bad? How? I'm not sure I understand.

The yeast is fermenting the wine, so technically that would be "going bad" I guess. But it's not like bacteria are suddenly going to multiply and take over the wine yeast, any more than at 80 degrees. Or 60 degrees.

It is hot here, 106 and not typical for us. No air conditioning just ceiling fans and fans on the floors. My black cherry fermented to 1.000 in 4 days. It was madly foaming in the primary when we racked it today. And I have never seen so much air lock activity once it was racked. It looked like must does after a couple of days after adding the yeast but was reading 1.000. I read that Lavlin 71B recommends 86 at the highest but I am sure the must was 90 degrees or more.

We moved it under the house where it is 70 as soon as it was in secondary.

So should I be worried?

Sammyk said:

It is hot here, 106 and not typical for us. No air conditioning just ceiling fans and fans on the floors. My black cherry fermented to 1.000 in 4 days. It was madly foaming in the primary when we racked it today. And I have never seen so much air lock activity once it was racked. It looked like must does after a couple of days after adding the yeast but was reading 1.000. I read that Lavlin 71B recommends 86 at the highest but I am sure the must was 90 degrees or more.

We moved it under the house where it is 70 as soon as it was in secondary.

So should I be worried?

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"Worried" is too strong of a word. Concerned about some potential off-flavors? Possibly. Sometimes super hot temps can encourage higher alcohols to form, called "fusel" alcohols. They produce a "hot" flavor in a wine that is the compound most frequently blamed for headache producers.

You can always use a water bath/ice bath to reduce the temperature, even in a 90 degree room. Next time, try that. Keeping the temperature in the 70s or thereabouts seems to produce the most dependable flavor in the finished products.

Thank you Yooper

Keep your vessel wrapped in wet towels. The evaporation action cools.