On some of my recent brews, I’ve had higher than normal OG’s. I know there are a variety of ways to adjust for this (assuming you don’t want to leave it as is), but I just came across a method that I hadn’t thought about before. Assuming you’re fairly consistent on your boil off amount, something I read talked about draining off a pre-determined amount of wort before you boil and replacing it with the same amount of water. I’ve heard of adding water to the collected wort to increase the volume and dilute it down before you boil, but not pulling wort and then replacing that same amount with water. The formula I saw was:
preboil volume-preboil volume*(recipe preboil gravity/actual preboil gravity)
I guess the advantage would be that you could keep the same volume in your kettle rather than adding to the volume that’s already in your kettle. Has anyone ever done this, and are there any downsides to the final beer that I’m not thinking of?