Full volume biab

[spanspoon]

Yesterday I brewed to a full length almost biab method...I'm using two vessels a 50 litre stock pot and a 49 litre coolbox, after a 60 minute mash then drain without a sparge.

I used the biab calculator from biab.info for amount of liquor required. I was astonished of how much it said I should use (42 litres) total mash volume was just over 46 litres.

I went with this, I struck my final OG of 1.040 but as I was pumping my wort from boiler to fv I left it for a coupleof minutes and on return I found that my tubing had fell from the fv and my garage floor soaked with fine wort! Gutted! Yesterday wasn't a complete waste as I still have 15 litres which is bubbling away.

Because I lost quite a chunk of wort I don't know if the quantity of liquor used was correct and 42 litres seems quite high to me. When I was using a 3v set up I used to start with 37 litres and finish up with pretty much bang on 23 litres. Is 42 a lot to start with?

Biab.info calc as follows

Brew length 23l
Fermenter trub 1.84l
Volume into fv 24.84l
Kettle trub buffer 4.14l (dead space in my boiler 0.6l, dead space in mash tun 0.6l)
End of boil volume 28.98l
Boil length 90 mins
Evaporation 6.81 l per hour
Total evaporation 10.20
Grain bill 5035g
Grain absorption 3.16
Water required 42.35l
Mash volume 45.68l

[Charles1968]

Since you hit your OG, the numbers are probably right. Seems a lot of kettle trub though.