# Help! Primary Ferment temp -- how hot is too hot?



## jtd1216 (Feb 22, 2012)

I have an RJ Spagnols Chilean Malbec Cru Select and Gewurztraminer Cellar Classic going in the primary right now. I had some trouble keeping fermentation temperature (only about 67F) for the first couple of days with the heat belt (only about 50F in my basement). Someone suggested putting a vented box over both primaries to hold in the temperature. The lids are cracked about an inch for oxygen. Worked like a charm. Overnight it got to 73F. When I got home today, 88F!!! I removed the boxes and popped the lids a bit more. The yeast is still going crazy by the way, more than I've ever seen in a kit. I know above 80 is a no-no, but did I ruin them?


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## AlFulchino (Feb 22, 2012)

you are fine...just punch down more frequently and keep the cap from holding in the heat...


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## robie (Feb 22, 2012)

Just guessing, but the temp probably went up so much because the wine started fermenting. Fermentation generates its own heat. Once the fermentations slows, the temperature will drop back again, so be ready to install the brew belts again. 50F is just too cold for the fermentation to complete properly.


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## Turock (Feb 23, 2012)

You are fine on the red,especially if you are fermenting on skins because that's where you get your color. But it's pretty warm for a white wine because you blow off the aromatics. A good temp for a cool ferment on a white is around 70 degrees.


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## Gr8zins (Feb 23, 2012)

I live near enough wineries that I've seen whites fermented in those dimpled refrigerated tanks to prolong primary. Correct me if I'm wrong but I have heard of some people fermenting for four weeks or more trying to preserve the delicate fruit flavors in the whites. So I guess a long fermentation on whites is preferable. Oh yea, I have felt the sides of my 16 gallon fermenters get pretty warm just from the yeast activity. It is definitely a factor.


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## g8keeper (Feb 23, 2012)

Gr8zins said:


> I live near enough wineries that I've seen whites fermented in those dimpled refrigerated tanks to prolong primary. Correct me if I'm wrong but I have heard of some people fermenting for four weeks or more trying to preserve the delicate fruit flavors in the whites. So I guess a long fermentation on whites is preferable. Oh yea, I have felt the sides of my 16 gallon fermenters get pretty warm just from the yeast activity. It is definitely a factor.


 
yes, some yeasts in particular will definitely generate mass quantities of heat. when i have used turbo yeast in the past to make my liquor base, you can truly feel heat just pouring off the sides of the carboy when that stuff is in full board fermentation....talk about activity???....that is really some wild stuff to watch cooking away.....lol....that stuff actually almost looks like "sea monkeys" swimming around it's such a violent fermentation....


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## winemaker_3352 (Feb 23, 2012)

Yeah - but the cold fermentations are for white wines.

Red wines need to be fermented warmer to aid in the color extraction from the skins.


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## robie (Feb 23, 2012)

Gr8zins said:


> I live near enough wineries that I've seen whites fermented in those dimpled refrigerated tanks to prolong primary. Correct me if I'm wrong but I have heard of some people fermenting for four weeks or more trying to preserve the delicate fruit flavors in the whites. So I guess a long fermentation on whites is preferable. Oh yea, I have felt the sides of my 16 gallon fermenters get pretty warm just from the yeast activity. It is definitely a factor.



Those extended fermentations do work well for whites. When Penfolds first started making their Grange, which is a red, they extended the fermentation of it to be like 6 weeks. They since have shortened the fermentation time. Grange is an exquisite (expensive) wine; was then, still is.

One thing about trying to extend the fermentation by lowering the temperature, some yeast strains can deal with this better than others, so read the yeast specifications and choose wisely. Otherwise, you can end up with a stuck fermentation. I would recommend one has several successful fermentation under one's belt before trying this. (Having had a couple of problem fermentations may help even more.)


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## Turock (Feb 24, 2012)

Personally, I don't like long ferments because as you lose the pressure from the CO2 that the yeast produces, you begin to worry about too much O2 exposure. We like fast ferments for this reason.


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## robie (Feb 24, 2012)

Turock said:


> Personally, I don't like long ferments because as you lose the pressure from the CO2 that the yeast produces, you begin to worry about too much O2 exposure. We like fast ferments for this reason.



I agree about long fermentations, especially very long ones. They can be risky. Trying to extend the time by very much should be left to the pros, who have all the "right stuff" for monitoring and control.


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## AlFulchino (Feb 24, 2012)

speaking of long ferments..i know of some taking six months


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## bstnh1 (Jan 23, 2014)

I maintain a pretty constant temperature during both primary and secondary by placing the fermenter in a deep tub of water and controlling the temperature with a simple submersible aquarium thermometer. My basement is cold inthe winter 45-50. I have the tub wrapped in 4" insulation and have a 2" think cotton insulation blanket over the top. I keep the tub water around 75, but I do open the insulation a bit during primary because of the heat generated by the fermentation.


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