Leigh Erwin: What's The Best Temperature For Wine Yeast?

Yeast Fermentation TemperatureHi all!
I just wanted to follow up a little bit more on the fermentation temperature “issue” I had noted in my last post. If you recall, the instructions for primary fermentation for my Chardonnay wine had a recommended maximum of 75oF, however, the heating pad I was using (that’s built specifically for winemaking) kept the wine at around 78oF. I was basically wondering if 3oF would really make that big a difference, and if it’s still feasible to ferment my wine at that temperature without any problems. Is staying below 75°F the best temperature for wine yeast?
Reading around the message boards and other sites, it appears as though there are a lot of people who have no trouble fermenting their wines at 78oF. The big thing to note here, however, is that it all depends on which specific wine yeast you are using. Some wine yeasts only function in certain temperature ranges, while others function at different temperature ranges. If I’m using yeast that’s still good through 78oF, regardless of what the range the kit instructions recommended it should still be fine.
So, what is the best temperature for the wine yeast I was using? I threw out the yeast packaging right after I used it and couldn’t find that information anywhere on the instructions or online, so I’ll have to just make a guess. I know I have used the yeast strain EC-1118 in the past, so I’m going to assume that’s the same one I used for this particular wine and go from there. Doing a quick online search, it turns out that the appropriate temperature range for EC-1118 is 50oF to 86oF. That leaves me plenty of wiggle room and my 78oF seems like it should work just fine for this particular wine and temperature combination.
For fun, I decided to look up the yeast profile chart on the Adventures in Homebrewing website to see what the temperature ranges for the other yeast types available are. Some wine yeasts are better for making dry white wines than others, and if I’m reading this chart correctly, it appears as though these are the yeast strains listed best to worst for making dry white wines: ICV D-47, EC-1118, K1V-1116, 71B-1122, and RC212. After a quick search for appropriate temperature ranges for each of these five yeasts, this is what I came up with:

According to what I found, most of the wine yeasts available from the yeast profile chart on the Adventures in Homebrewing website have incredibly wide ranges of temperatures at which they can survive. As long as I wasn’t using the ICV D-47 yeast, the temperature that my heating pad made my wine (78oF) should be just fine.
It kind of makes me wonder though, why do the kit instructions say to ferment no higher than 75oF? Could they be assuming the winemaker might be using any number of wine yeasts and this is just the average high temperature that is appropriate? I suppose perhaps at the higher (or lower) temperatures you can still make the wine just fine, though the specific dates for each step will change depending upon that bit of information. Keeping it no higher than 75oF probably maximizes the likelihood that the wine will progress in the time frame specified by the instructions.
Does anyone else have any insights for the best temperature for wine yeast?
leigh_erwin_bioMy name is Leigh Erwin, and I am a brand-spankin’ new home winemaker! E. C. Kraus has asked me to share with you my journey from a first-time dabbler to an accomplished home winemaker. From time to time I’ll be checking in with this blog and reporting my experience with you: the good, bad – and the ugly.