Hop utilization in large boils

Hi everyone, I know that an all grain wort (6gal.+) has 25%+ more hop utilization than an extract wort (2gal.) for bitterness, but what happens when you get to a 12 gal. boil. Does the utilazion keep increasing at such a rate. I'm considering going bigger, but I want to know how to adjust my recipes. While I'm at it, does anything else change with larger quantities? I assume mash and sparge calculations just double. Thanks in advance.

No, utilization is a function of sugar concentration, not volume. Full volume boils are lower in gravity so accept more bitterness. It would be the same with a "double" batch. As the batches get much bigger, like multiple barrels, utilization does go up more but not to worry at the homebrew scale.

Yeah, what he said. Download the trial of a program like BeerSmith. You can adjust top off amounts and get your hop utilization calculated for you.

Thank you both, Sugar concentration makes perfect sense. Viscosity!