Mash tun dead space

Wagging Stumps

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Aug 19, 2013
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New and have question on mash tun dead space. I have a bottom drain keg I use for a mash tun. Since this is not technically dead space as I recover all of that volume when I drain, how do I account for this in calculations such as grain ratio and mash and sparge volumes. The volume underneath the false bottom is 1 gallon. So when I mash I usually add 1 gallon to the mash volume and subtract 1 gallon from the sparge . How do I do this with brewers friend?
In that case your mash tun dead space is zero since you are not leaving anything behind.

The brew feature's mash calculator allows specifying the strike volume as a mash thickness or simply a volume.

It is debatable if the volume under the false bottom counts towards total mash thickness (the enzymes, starches and sugars dissolve into the solution, though more of it is happening right in the grain bed). If you recirculate the mash, I would say the answer is a big yes. If you don't recuriculate, it isn't as clear to me.

The easiest thing to do if you really want to cancel out the false bottom would be to increase the mash thickness by ~0.4 qt/lb to reflect the extra space (if your recipe has 10 pounds of grain, that will work out to 1 gallon of additional strike water).

From there the remaining sparge water will automatically work itself out in the water requirements section.