What are some important factors that account for mash efficiency? On my last mash I did about 90% efficiency vs the usual 72%. Obviously, I'd like to get 90% every time, but I don't know what I should adjust. Things different from previous brews were mash ratio (1.5qts/lb), rest temperature (I usually do both a beta amylase/limit dextrinase rest and an alpha amylase rest, but this time I did a single rest at 149F), and mash pH (added slightly over half a pound of acidulated malt). Are any of those things more likely than the others to increase efficiency by so much?