We just returned home from visiting family out of state and along the way acquired a 48 qt. Igloo Marine Cooler. Now that I have it, I was thinking about using this cooler as a mash tun in place of the 70 qt. Coleman Extreme cooler that I’ve been using (without complaint). My reason for scaling down to the smaller cooler would be that since I only brew 5 gallon batches (batch sparge), I would have less head space in the smaller cooler, with the option of returning to the larger one for a big beer that needed the extra room. My question is: could I expect any difference in efficiency (for better or worse) by moving to the smaller cooler if I keep the rest of my process the same? I thought that one perk might be more consistent mash temps since more of the volume of the cooler would be taken up with grains and water, but didn’t know if there would be a significant change in efficiency.