Will Excessive Temperature Effect My Brew?

[threeheads]

I wonder about temps, and hope to get some clarification. The nasty (fusel?) alcohols are created when ? While the yeast is at it's most vibrant, or right througout the process ?

I ask this, bcause I can pitch at around 18c and keep it there until krausen, but after that, I'm babysitting the drum at variations between 20c & 24c. And after day five (after the yeast has finished it's hardcore feed) I can keep it around 22c.

I'm assuming that the strong yeast movement has an impact on the wert temp?

With active fermentation there is a small chemical reaction happening. This causes the temperature to rise quite a bit. I know that even during the winter months in canberra I find my fermenter temperature rising despite the temperature outside. It does make quite a bit of difference.