Well, I got a good lesson in what esters are in my last batch of Kölsch-style ale. Lalbrew's instructions for rehydrating their Nottingham yeast say you can add the yeast to water that's 30-35°C. So, I felt it would be okay to pitch the rehydrated yeast into the wort when it was 35°C.
The next morning, when I lifted the cloth cover of my open fermentor, there was a strong, fruity (but not unpleasant) odor.
#Kölsch
#homebrewing
#UpperWillamette
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