I have recently started with BIAB and have brewed 4 batches, two low alcohol ( 2 pale ales of 6% and 5.3%) and two high alcohol ( wee heavy 8.6% and barleywine 10.3%). However, I notcied my mash efficiency is different between them. For two low alcohol batches it is around 77%, but for two high alcohol batches is about 67%. I did not change the gap between the grind and used the same method, using Beersmith to calculate the water-to-grist ratio and mashing temperature. Is this difference normal? If yes, I should change the mash efficiency in the profile before each brew in the future? Thank you. Cheers.