If I Cook My Coffee At 30 Degrees For 2 Hours, How Long Should I Let It Cool?

It depends on the room temperature but you need to keep it for 10 mins if the temperature is less than 10 degrees or 20 minutes if it is less than 20 degrees. Its a simple rule of thumb.

Your coffee is never going to be hotter than 30 degrees. It's cold, like frozen isn't it? 32 degrees is freezing in ferenheight. You'll have to let it THAW, not cool. Hope you like iced coffee:)