Until now I have been using a Peco boiler for BIAB doing 23 litre batches. I never paid much attention to what the grain to water ratio was but followed the same process every time of filling the Peco right to the brim (about 35 litres) then treating this water as required. I’d then draw off 5-6 litres of this into bottles and put aside to heat up. This was my sparge water. There was now enough space in the Peco/bag to stir in 4-5 kg grains and create a thin mash.
At the end of the mash I’d use a pulley to lift the bag out and drain whilst slowly pouring the heated sparge water over and through the bag to rinse the grains until I was about half a litre short of my Pre boil volume then squeeze the hell out of it which usually gave me the last half litre I needed. This gave me a consistent BHE of about 70%
I say until now. I’ve just bought a Brewzilla but haven’t used it yet. To be honest, I’m a bit scared of all the posts I’ve seen about stuck mashes and stuck sparges. I’ve never had any of these issues and sort of wonder if I should have just stuck with the old kit!
I think I might just use similar mash water volume with my Brewzilla as I have been with the BIAB in the hope the efficiency will be as good, if not better, if only due to the mash being recirculated constantly as opposed the the 2-3 stirs it used to get.