I have brewed about 30 batches using BIAB, and I have always had my LHBS double crush the grains, giving me efficiencies in the high-70s (I also squeeze the bag and "sparge" to bring the volumes up). I now have a larger kettle and now have the room to move to a no-sparge process and more grain in the kettle if needed. I'm now trying to figure out the best crush size for the beer quality with less concern for mash efficiency. Today, my first no-sparge brew with a single-crushed grist of 95% 2-row/5% C-40 had a mash efficiency of 62% at a pH of 5.3 and temp of 152. This is OK, but I'm wondering if there is a downside to increasing the grain crush. Obviously no worry about a stuck sparge with BIAB, but are there other concerns? Any thoughts are appreciated.