Very High Spike in Fermentation Temperature (did I just ruin 100 gallons of must?)

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Jay204

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I raised the ambient temperature in my winemaking room (my garage) in an attempt to spike fermentation temperatures, as I have done in the past without issue. However, this is the first time fermentation temp's have spiked so drastically and so much higher than ambient temp. An ambient temp of 25°C (77°F) caused my fermentation temp to hit 40°C (104°F). I lowered the ambient temp but the must probably spent the better part of a day at this temperature. Of course brix is dropping fast too - it is a very vigorous fermentation.

For anyone that's experienced this, did I just ruin 100 gallons of Petite Sirah must? I'm worried about cooking the wine, ruining the flavour or getting a stuck fermentation. Nothing smells 'off' so far.

The yeast used was Zymaflore FX10. The top range of the temperature for this yeast is stated to be 35°C.
 

NorCal

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There is nothing you can do about it now. I wouldn't be too concerned until the wine has aged for a year. I do remember a Barbera that @4score made that did a very similar thing. He ran out and got dry ice and did all he could to get the temp back down. The wine ended up winning double gold, best of class at the California State Fair (competing against around 30 other wines).
 

Jay204

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@NorCal coincidentally, the other wine in the garage is a Barbera that started out at 27 brix... It spiked too, but not quite as high. It smells amazing and the sugar depletion has been much more normal, so I'm not as concerned about it. Now I have to make the decision to either press the Barbera early, or leave the Petite Sirah for a day or two after it has gone dry (as long as no stuck fermentation), since I borrow the press from my supplier and can't keep it for several days. Leaning towards pressing the Barbera early.
 

CDrew

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I, too, have to ferment in a sometimes hot garage. I've hit low 90s F before never above. The wine does ok with this. You might get some "jammy" or cooked flavors but I'll bet it will still be very good in time.

It sounds like you used a yeast that tolerates a lot of heat(35C), so my guess is that your wine will be just fine.
 

Steve Wargo

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I raised the ambient temperature in my winemaking room (my garage) in an attempt to spike fermentation temperatures, as I have done in the past without issue. However, this is the first time fermentation temp's have spiked so drastically and so much higher than ambient temp. An ambient temp of 25°C (77°F) caused my fermentation temp to hit 40°C (104°F). I lowered the ambient temp but the must probably spent the better part of a day at this temperature. Of course brix is dropping fast too - it is a very vigorous fermentation.

For anyone that's experienced this, did I just ruin 100 gallons of Petite Sirah must? I'm worried about cooking the wine, ruining the flavour or getting a stuck fermentation. Nothing smells 'off' so far.

The yeast used was Zymaflore FX10. The top range of the temperature for this yeast is stated to be 35°C.
If you can. Give it a taste test. You'll know right away if it's going in the wrong direction. Though, I bet you are ok.
 

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