On my 3V I let Beersmith do the maths for me, and just dial it up so I'm just shy on my pre-boil water level. It's easy to add 1/2 a litre, than to remove it.
There is a another way to adjust water for differing grain bills. On my 1V upfront say I don't give a f.... I have three marks 32, 29 and 25. I don't adjust water levels to suit grain bills. Strike 32L, mash etc.. Remove the BIAB, drain for a sec into the kettle and drop the bag into a bucket. Check my vols. On a smaller grain bill I will be already at 29L, on bigger ones I will need to pour some drainings from the bucket back into the kettle; on really big grain bills I may need to sparge the bag a little to get more vol from the bucket, to achieve my 29L level. From here on our the 60min boil from 29 to 25 is all constant.
If you are BIAB'ing brewing bigger beers in a small vessel and are having issues with the vol of strike water plus grain, just leave some water out up front. Add it as part of a sparge routine. Back when I use to traditional BIAB I always allowed a 3L sparge water addition.
QldKev
There is a another way to adjust water for differing grain bills. On my 1V upfront say I don't give a f.... I have three marks 32, 29 and 25. I don't adjust water levels to suit grain bills. Strike 32L, mash etc.. Remove the BIAB, drain for a sec into the kettle and drop the bag into a bucket. Check my vols. On a smaller grain bill I will be already at 29L, on bigger ones I will need to pour some drainings from the bucket back into the kettle; on really big grain bills I may need to sparge the bag a little to get more vol from the bucket, to achieve my 29L level. From here on our the 60min boil from 29 to 25 is all constant.
If you are BIAB'ing brewing bigger beers in a small vessel and are having issues with the vol of strike water plus grain, just leave some water out up front. Add it as part of a sparge routine. Back when I use to traditional BIAB I always allowed a 3L sparge water addition.
QldKev