# Fermentation Temp



## pkeeler (Jan 12, 2011)

I'm about 2 days into fermenting some previously frozen crushed grapes. This is my first batch, so I'm probably obsessing a bit LOL I read everywhere that red wine should be fermented between 80-90 deg. But what temp. is everyone talking about? I took temp. this morning and the cap was 93 but the juice under was only 83. There seems to be a pretty consistent difference in temp. between the cap and the juice. So, when sources specify a temp. (such as Lalvin for their yeast), are they talking about juice temp or cap temp?


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## djrockinsteve (Jan 12, 2011)

80-90 degrees is high. I myself prefer to ferment in the 70's during the Sept.-Oct. time. Other times I prefer to ferment at a lower temperature even as low as 65 degrees.

Lalvin is a great yeast to use and has the ability to ferment from low to high temps. specific strain pending. I believe if you are fermenting that high you will loose a lot of the flavor that your fruit has to offer.

That being said sometimes you can't help these higher temperatures and have no choice. If possible I would recomment fermenting in the 70 degree range and I would take the temp. after stirring.


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## ibglowin (Jan 12, 2011)

You didn't mention whether this was a Red or a White but more than likely its a Red so I'll go with that. Red's can take higher temps than Whites. The higher temps will help with color extraction from the skins. At those temps you would lose a lot of volatile flavor compounds in a White which is why they are fermented at comparatively low temps.

When they speak of temps they are talking juice temps. Punch down your cap, stir it up and then take a temp reading of the mixture. 83 is not all that high for a bucket of frozen crushed grapes. It would be high for a kit wine. If you have a high air temp that will contribute to those higher temps as well.

Oh and welcome to the Winemakingtalk forums!


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## winemaker_3352 (Jan 12, 2011)

Welcome aboard!!

I agree with Steve - i think he pretty much nailed it!!


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## pkeeler (Jan 12, 2011)

Thanks for the help everyone  The ambient air temp where the fermenter is is about 60. (Newbie mistake, set fermenter exactly where you want it before adding 150 lbs of grapes). Since the grapes were frozen, they were not getting warm enough for fermentation to start. So I enclosed them a bit with a space heater. Once the must got to 65, it took off. I've now unwrapped it and turned the heater off. The top of the juice is 81 after stirring. Good to know that is the temp I should be looking at. Those 90-95 deg. cap temps almost had me reaching for ice or something.

It is a red wine, 100% malbec.


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## Calamity Cellars (Feb 7, 2011)

83 F Juice temperatures would be normal to a bit low for me with red wines. Color & flavor extraction from the skins is a function of time & temperature. The higher the temperature the shorter the time. Some will argue that a lower temperature will allow more time but the science does not back this up. Definitely do not base your temperature decisions on the cap but on the juice itself. I Prefer to get my red wines up into the ninety's and don't start worrying about yeast health until I get to 100F. This is all based on the presumption that we are talking reds.


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