Hey guys,

In my head I figured I could do this math, but every single method I tried yielded clearly incorrect results. Here’s what I’m looking for.

I just brewed up a batch and had a measured OG of 1.070, however I also ended up with about 4.5 gallons of wort instead of the 5 I was shooting for. I was way over on my efficiency estimate though, so I figured I would just top it off to the 5.0 gal mark. This was I have a bit more beer, and it will bring down the gravity more into the range I was shooting for anyway. However, no matter what way I tried to work the math (and I tried 2 or 3 ways) I kept getting clearly incorrect results. Apparently I either don’t remember how to do my weighted averages or that math wont work here.

At any rate, can someone share the correct formula for figuring out the new OG with the extra half gallon of water added?

Thanks fellas,