no, the esters (isoamyl acetate is what give the banana flavor) formed during warm fermentation, not during rehydration. They need sugars in order to produce any outputs. Rehyrdration simply re-wets the yeast cells and allows the cell wall to become permeable again.
Fermentation is exothermic. In other words, it creates heat. The beer temp is often several degrees above ambient, so if your chamber got up to 80, your beer was even higher.
HTH-
Thank you! I probably would have known this had I placed a sticker thermometer on the carboy, but one was never placed in the kit we purchased and since i'm impatient and wanted to brew before we got one, I figured I could just use the stick thermometer to keep an eye on the water that the carboy was in. Since that thermometer broke, I was just testing the ambient water with my hand. Now, because of you guys, I know that the temperature of the beer is often higher, and therefore I need to measure it instead in order to keep it at the correct temp.
We have since bought a ticker thermometer that attaches to the side of the carboy.
Now my question is this: When the carboy is placed in the bucket of water, shouldn't we fill the bucket to so the water is level with he fermenting beer that's inside? In my mind, this would allow for equal temperature regulation. But if I do that, then the sticker thermometer that I place on the outside of the carboy to measure the temp of the beer will also be submerged in the ambient water. How do I get an accurate reading of just the beer, since that is what I should be most concerned about?
I know these questions must be so mundane, but as a beginner, the answers are extremely helpful! I've learned so much already!