New BIAB guy, Water Volume Question

[LoudMic]

Hi, I'm Mic, and I'm a brewaholic.

I'm new to the forum and new to BIAB.
I've been extract kit brewing for a number of years. 2 weeks ago I brewed my first BIAB, a Blonde ale. I got help from LHBS getting the grain bill, based on an extract recipe have had success with.

The day when great and I really like the process and fewer dishes to do. the only problem was I came up almost a gallon short and had to top off.

so I am now looking at some recipes here and wonder, is the "Boil Size" post mash? or is that the volume of my strike water?
if it is post mash, how to I calculate the additional water needed to account for what the grains soak up?

thanks
Loud Mic

 

[J A]

Depending on several factors, milled grain retains .25 to .5 quarts per lb. I have my system profile set to .4 qt/lb and I do a slow sparge with a standard mash tun set up. If you drain your bag over the pot for a while you'll have less absorption. If you sqeeze the heck out of your grain bag, you'll have very little loss. If you're just draining, start with .3 and if you're squeezing, try .25 or so. If you assume less absorption and you end up with less volume than you need, you can always top up as you did. If you assume too much absorption and it doesn't soak it up, you could end up with way too much to boil off and be way over volume and under gravity. Once you have an idea of how your system and procedure is performing, you can tweak the setting or calculation and hit your targets better.

Boil size is post mash, pre boil. Batch size is what goes into the fermenter or what's left in the pot after boil, depending on which target you check (fermenter or kettle).

All those little question mark boxes beside the recipe settings will give you specific information about the particular values you're working with.

 

[LoudMic]

Depending on several factors, milled grain retains .25 to .5 quarts per lb. I have my system profile set to .4 qt/lb and I do a slow sparge with a standard mash tun set up. If you drain your bag over the pot for a while you'll have less absorption. If you sqeeze the heck out of your grain bag, you'll have very little loss. If you're just draining, start with .3 and if you're squeezing, try .25 or so. If you assume less absorption and you end up with less volume than you need, you can always top up as you did. If you assume too much absorption and it doesn't soak it up, you could end up with way too much to boil off and be way over volume and under gravity. Once you have an idea of how your system and procedure is performing, you can tweak the setting or calculation and hit your targets better.

Boil size is post mash, pre boil. Batch size is what goes into the fermenter or what's left in the pot after boil, depending on which target you check (fermenter or kettle).

All those little question mark boxes beside the recipe settings will give you specific information about the particular values you're working with.

Thank you! that's exactly the answer I was looking for. I do plan on squeezing and hanging the bag for quite a while post mash. I built an ugly, yet sturdy hoist a couple weeks ago. I'll start with the recommended .25 and top of if need be. Then make adjustments from there.

Cheers!
Mic

 

[Craigerrr]

Great advice from JA (as usual). You will find it very satisfying to hit your targets consistently, once you get your water volume calculations dialed in. Make good notes, and count on 2-3 brews to fine tune it.