How does fermentation temperature effect a wine?

Cellar Rats (ITB)
1

For example what does a “cooler” fermenetation do to color, body, aroma and flavor? What does a “hotter” fermenetation do to color, body, aroma and flavor?

Thanks.

2

Surprised no debate on this.
It seems to be commonly accepted that warmer temps bring darker color and more extraction. But opinions vary on aroma with some saying cooler preserves aromatic and others suggesting warmer temp do the same.

3

Thanks steve

4

I think that you lose a sense of delicacy at higher temps.

5

the particular lot of fruit in question has as much impact as anything. Riesling and Syrah fermented at the same temperature will give you different degrees of success or failure because Riesling and Syrah are not the same. In case you hadn’t noticed… [swoon.gif]

6

This is far from the complete story, but a couple of small points:

In reds, if the temp is too high ferm will complete quickly, which will not allow flavors to develop fully. Tannin will come from the high temp, but not full flavor.

In aromatic whites, like SB, the prevailing wisdom had been cool temps (50’s) was best, but research is showing that 60-68f is ideal. I think cooler temps preserve primary aromas, but don’t allow secondary ones to develop fully.

Some of you red wine gurus must have something to add.

7

Thanks guys

8

Hotter temps increases extraction and cause more blowoff of volatiles but also stress yeast (which can be good at a certain point but turn very bad if it gets too hot and the ferment sticks). Cooler ferments reduce the amount of extraction, slow the speed of the ferment and can encourage certain native (good and bad) yeasts to thrive, but also retains more of the fresh fruit aromatics in the wine.

Most fermentations in my mind would ideally have a long cool start and then a short hot phase towards the end, say in an ideal world 4 days of 10C, 6 days between 10C and 25C, peak at around 30C no more then 35C for a day or two and then slowly cool off for a day or two depending upon the quality of tannins, flavors etc, going down to barrel at around 20C or so.

This varies dramatically if you want a more fruit forward style (cooler ferments) or a more robust style (hotter ferment). You’re boxed in by where yeast will thrive as for the most part its in between 10C and 35C (with some individual strain exceptions). Also depending upon the vintage, fruit, varietal, style goals etc, you’re exact desires may and will vary…
Great question,
Brian Maloney
DeLoach Vineyards

9

Berry –

One example you might find interesting was the old Cordier wines from Bordeaux: Gruaud Larose, Talbot and Meyney. They fermented at what were then fairly high temperatures for Bordeaux – around 30C. While these wines could be very good, I don’t think they had the refinement of their peers. Certainly Gruaud was always much more four-square than other second growths. I always wondered if that was partly the temperatures.

10

Sorry to arrive late at the party. It’s not higher temperatures in and of themselves that affects the degree of color extraction, rather, it’s when they occur during the course of a wine’s fermentation.

11

David, that’s exactly what I was going to say. Timing is as important as temperature.

And Brian, you describe the curve I"m looking for in Pinot noir. Long cool soak, naturally warming up to a fairly high peak, then dropping and you’re done. Or you can let the ferment hang out if you’re still getting good things, or not getting bad things out of post ferment maceration.

At least that’s where I am in my evolution of fermentation management.

12

My experience with pinot is that cooler temps yield simple strawberry/raspberry flavors. I want that to be a minor note in the blend, but I want the majority of the fermenters to get pretty hot – peak around 93 F. Besides just being darker, I think the higher temp lots are earthier and deeper – less primary. I agree with Brian that I want the peak to come fairly late. Pinot can be pretty hard to rein in if it spikes early, and your fermentation can race through in a couple days. I think that if you turn it loose a little later (say around 13 brix when there is starting to be some inhibitory alcohol in the must) it’s easier to keep the pace in check even at higher temps.

13

Thanks for the interesting posts.