# Best temp to ferment D47



## brottman (Sep 3, 2015)

Topic says it all. I now have good temp control and want to do a traditional with D47. I know D47 likes it cooler. What temp should I dial in for it?


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## BernardSmith (Sep 3, 2015)

The technical data sheet suggests that optimal temperature is between 15C and 20C (59F - 68F) but I assume that since fermentation produces heat you want the ambient temperature to be about 10 degrees F lower....


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## Deezil (Sep 3, 2015)

I'd go for about 65F for the first day or two, until the ferment got going, then I'd drop it down a few degrees - maybe even as low as 60F.


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## 4score (Sep 3, 2015)

I just fermented with D254 in a cool room. Room temp was about 66 F and when fermentation temp was peaking, at about 58% through, the must temp spiked to 84 F. So, that's 18 F difference at peak. Can you go as low as 50 F?


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## brottman (Sep 3, 2015)

With my new freezer setup, I can go anywhere from room temp down to -40c, not that I would ever need it to go that low!


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## botigol (Sep 4, 2015)

Do you have a separate sensor to control the temp or just the built-in thermostat? If you have a separate sensor I would recommend placing it against the side of your fermenter, covering it with an insulator (bubble wrap, cloth, shelf liner) and then tape the insulation into place. If not, a variation of Deezil's advice sounds good to me...start at 65F, as soon as you see active signs of fermentation drop the temp 2-3° every 8-12 hours until the ambient temp is in the mid to upper 50s, then after five days (or when you rack to secondary, whichever comes first) increase the temp back up to 65F. The ramp down is to help prevent causing the yeast to go dormant from the temp change. The temp increase at the end is to ensure that the yeast finish their job.


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## 4score (Sep 4, 2015)

I like the idea of gradually tuning the temperature down as needed. IMO, I don't think "upper 50's" will be low enough to handle peak fermentation. I think you'll need 50 F ambient for that peak period.


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## brottman (Sep 29, 2015)

Just an update on this. I've been fermenting this at 60F must temp. I started with an SG of 1.115, and this yeast just will not die. I've added about another 5lbs of honey into this 6 gallon batch to get it to end somewhat sweet, but the damn yeast just keep going. D47 is rated for 14%.... but I'm probably pushing 18% now. Tastes good, but one glass gets you pretty buzzed


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