I've started missing gravity targets lately, and I'm a little confused by it because my pre-boil gravities seem to be on-target, or at least in a range close enough that I SHOULD be hitting them.
For example, my last brew was target OG 1.065.
I had 7.5 gals of (observed) 1.033 (@ 140 deg) wort, which converts to ~1.046.
A 75 minute boil should have given me ~5.5-6.0 gal at 1.063 (according to BeerSmith's boil-off calculator, using my empirical values).
Instead, I had 5.5 gals at 1.055 (at 78 deg), converted to 1.057.
What am I missing?