Originally Posted by soylentred
I fermented at 65F. The LHBS told me to rest at 55-60F for 24-48 hours, that seemed to jsut make the diacetyl smell worse.
OK so doing a diacetyl rest at a temperature LOWER than your fermentation temperature makes absolutely no sense. Diactyl reduction will SLOW DOWN as you reduce the temperature of the beer. If you are going to do a diacetyl rest it should be at a temperature HIGHER than your fermentation temperature.
The temperature of the diacetyl rest is really not something you should be worrying about. At 65F the yeast will re-absorb the diacetyl rather quickly, and a diacetyl rest is probably a big waste of time and energy. Fankly I wouldn't bother with a diacetyl rest for ales at all, since the fermentation temperature is generally high enough to re-absorb the diacetyl in a very reasonable amount of time.
However if you choose to do a diacetyl rest because you don't want to wait for the diacetyl removal (remember this will happen at normal fermentation temperatures anyways) you will have to raise the temperature. Lowering the temperature will have the opposite effect of what you want, and will be a big waste of time/energy.
Hope that helps.