Mash Water Volume Calculations for New Setup, Thoughts?

[DNelson]

Moving from mashing in a cooler to a larger three pot HERMS system. Also interested in increasing my liquor/grist ratio to 2.0 after reading that's about what Strong uses, and after reading some of Kai Troester's research as well.

Ran some numbers and came up with the following.

For a pre-boil volume of 14.75 gallons, 28 pounds of grain, at 2.0 qts/lb, 2.5 gallons of dead space under the false bottom, and 0.13 gal/lb absorbed by the grain, my mash water is coming in at 16.5 gallons leaving only 2 gallons of sparge water.

Seems odd to use so little sparge water. Seems like I may as well go for no-sparge at that point, add all of the water and throw in a bit more grain if I can fit it.

Any thoughts?

 

[doug293cz]

Since you're going to be recirculating the mash, the liquid under the FB will pass thru the grain bed several times during the mash. This is quite different than in a non-recirculated mash. I'd ignore the volume under the FB when figuring mash thickness, giving you about 4.5 gal to sparge with. That should work if you are fly sparging. If you are batch sparging, you really need to do something to minimize the volume under the FB, as you won't get a good batch sparge with that configuration (although, recirculating the sparge water for long enough to get 2 volume turn-overs would help a lot.)

Brew on

 

[DNelson]

Since you're going to be recirculating the mash, the liquid under the FB will pass thru the grain bed several times during the mash. This is quite different than in a non-recirculated mash. I'd ignore the volume under the FB when figuring mash thickness...

Would re-circulation make mash thickness irrelevant? I'd expect that the mash thickness the grains are actually sitting in would have an impact on conversion/efficiency. (To whatever extent it actually does impact these things. I'm aware that most aren't too concerned with mash thickness)

If I were to ignore the dead space, that would effectively put my mash thickness at 1.6 qts/lb. I guess that's fine either way, so probably no reason to fuss over it.

...That should work if you are fly sparging. If you are batch sparging, you really need to do something to minimize the volume under the FB, as you won't get a good batch sparge with that configuration (although, recirculating the sparge water for long enough to get 2 volume turn-overs would help a lot.)

I've always batch sparged in the past, but I'm interested in switching over to fly sparging.

Maybe I ought to construct a different false bottom either way, just to give me more flexibility. I have the More Beer FB and it sits 1.75" off the bottom.