Originally Posted by dandw12786
Hey just wondering about fermentation temps. Let's say I want to ferment at about 68... are we talking about the temp of the room, or the temp of the actual beer? Should I keep the beer in a room with a lower temp or higher temp than I want to be fermenting at? And temp is really only a concern with the first part of fermentation, right? The rest of the time it's in the primary clearing up, the temp can go up a bit without problems, correct?
You want to have it be the temperature of the fermenting beer, not the ambient temperature. In a warm room, the fermentation temperature can be as much as 8-10 degrees warmer inside the fermenter than the ambient temperature. In a cool room, the temperature may be very close to the same or only a couple of degrees warmer. Fermentation itself produces heat, and it gets even hotter in a warm environment. In a cooler environment, it's more slow and steady. I have a couple of stick-on thermometers, called fermometers, for the outside of my fermenters so I can see the temperature.
I've heard that some people only control the temperature during primary, but I control the temperature the entire time. It may not hurt the beer much to let the temperature rise, but I don't see the benefit of uncontrolled temperatures after primary. A few degrees is fine, and a good idea, if you're going from say 65 degrees to 68. But I wouldn't ever let the beer get above the yeast strain's optimum fermentation temperature.
The fermentation temperature usually depends on the yeast strain you're using. Some strains are pretty forgiving of 70+ temperatures, but some are not.