False bottom dead space

The more I think about home brewing, the more I realize I need to learn. I am in the process of changing from (usually) partial extract to all grain brewing with a HERMS setup. Thinking about my mash tun, and where to locate the false bottom. For HERMS, given the recirculation, does it matter if the false bottom is relatively high from the bottom of the kettle, say 2-2.5"?, or would it be better to minimize the space under the false bottom (about 2 gallons for 2.5").

If the false bottom is elevated to 2.5", how should the mash volume be calculated? Include the volume under the false bottom, or not?

Thanks,
Mike

To me, even if you're recirculating, you'll still always have X gallons of liquid underneath that false bottom not in contact with your grist. Think if you were doing a small-ish batch that only required 3 gallons of strike water under a normal mash ratio - you'd have ~2 gallons underneath and only 1 gallon for the grain bed. It would be appropriately muddy vs. if you had the normal 3 gallons in there.


I recirculate and I measure the volume under the FB and add it on top of my normal volume calculations. Just my two cents.

Makes sense.

Thanks for your response. I was beginning to think nobody had any advice on this.

I have the same amount of dead space and I also add 2 gallons on top of whatever I need for the mash. The only time it becomes a problem is if you want to batch sparge (I don't always have time for fly sparging) because if you add an extra two gallons to your second batch you kill gravity. So if you batch sparge just be very careful to never add more sparge water than you actually need to make your boil volume.