I read that you should rehydrate dry yeast. Fine, I get that. The manufacturer says to use 100F water for the hydration period. Great. It then says to drop the temp of the rehydrated yeast to within pitching temp. That means I have to drop the temperature 50 degrees to 50F? Talk about temperature shock. I have 30 minutes to do this. Seems to me a tall order. How to you guys do this without shocking the yeast?