Uh oh, too warm...
 

Hey all. I just brewed my first all grain batch and set it in a water bath in the basement. I thought that would be cool enough, but I'll be darned if the temp wasn't still at 78 F when I checked it this morning. The ferment is already going like crazy. I'm going to improve my cooling technique when I get home, but does anyone know if its too late to make a difference? I only pitched the yeast at about 5 PM yesterday.

Throw a wet towel around it and put a fan on it. I actually leave mine in the tub and drip water on the top from the faucet, while the fan is blowing on it. You'll knock off at least 10-15°F off ambient with this method. The evaporation of the water sucks the heat out of the fermenter...

Well, since the fermentation is rolling and it's most likely for it to get even warmer during the day, expect some fruity esters. It won't hurt to cool it a bit, but the final result will depend on the yeast you used.

I'd be careful about temp fluctuation. If you do it, do it very slowly---quick drops or jumps can stress the yeast and lead to off-flavors.

Along the lines of what david posted, what yeast did you use?

I used Wyeast London Ale yeast. Never used it before, but supposedly already a bit fruity. Hmmm...