So my boil kettle is a little bit larger in diameter than most I see out there. And my OG comes out higher and my yield comes out lower than expected. I'm thinking that maybe my kettle is boiling off more water than others. Should I do something like use more water?
I ran into this problem when I bought my 15 gallon pot for 10 gallon batches. I got it at a discount from a friend who has a membership to a place that sells equipment directly to restaurants and such so I didnt get to pick it out myself. The increased surface area creates more boil-off than a more narrow/tall pot, which makes no difference other than an increased amount of boil-off. Just account for that in your pre-boil volume so that you hit your desired amount after your done. Maybe the increased amount of boil off is a good thing considering the fact that off-flavors go along with the steam.