I've read tidbits how that after the first 3 days of fermentation, you would ideally raise the temperature of the carboy for the remainder of the brew.
How, exactly, does one do this?
Say the Wyeast I buy states an optimal temperature range of 60-72*F (15.5 to 22.2*C), and I don't know enough about the flavor profile at different temperatures of a yeast, so I arbitrarily decide that the midway point is going to be my target temperature.
For the first three days I hold the temperature at 66*F (18.9*C).
Given that (I've heard) only 50% of the batch is brewed in the first three days, why would I want to raise at all?
Assuming I want to raise,
1) Do I raise after 3 days or some other amount? (Rule of thumb here as I'm not going to take gravity readings)
2) how much do I raise the temperature by?
3) how many hours/days do I take to raise the temperature?
4) do I hold it at this temperature for the duration of the brew?
Incidentally, I have 8 carboys going but only 4 fermwraps. Four of the carboys are closer to the end of the brew, and four of them are closer to the start. Is it more important for me to raise the temperatures towards the beginning of the batch that to maintain a raised temperature at the end of a batch?