Different dates, I’m thinking from weekend to weekend. I usually ferment for three weeks. I was thinking having the probe attached to the first beer and then switch it to second beer a week later.Same starting date or different? Your beer really only needs active cooling while it is in the early stages of fermenting. By day 3 or 4 you can let it warm to room temp with no problem as the fermentation where the off flavors is produced is over (big beer exceptin, they take longer). As long as you are brewing them a few days apart you can do as many brews as you want.