Originally Posted by bullrider4
I hear a lot about guys taking a pre-boil hydromter reading and a post boil hydrometer reading.. I have always taken only a post-boil reading before pitching yeast.. What is the advantage of the pre-boil reading? Is it for figuring mash efficiency?
It's actually for figuring efficiency. I use it for a couple of reasons- one is that I'm still figuring out my efficiency since I got my new barley crusher. My efficiency is much higher than it was- so if I know my efficiency I can adjust my hopping so that I still get the correct IBU/SG ratio and the correct amount of IBUs. Another reason is if your efficiency is low, you can add some DME before the boil to boost the OG up so that your beer is still balanced. I guess that's only one reason, when you think about it.