Best mash thickness for HERMS

I'm starting to build a HERMS system. Do people find that a certain mash thickness is needed for the HERMS to best work or can you vary between the 1-2qt/lbs ratio without any notice?

beeguy said:

I'm starting to build a HERMS system. Do people find that a certain mash thickness is needed for the HERMS to best work or can you vary between the 1-2qt/lbs ratio without any notice?

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I think the important thing is to make sure that you have enough liquid to fill your pump/coil loop and maintain a couple inches above the grain bed in the MLT during the circulation.

I use about 1.5 qt/lb and could use less if I wanted to, but I'm pretty sure I couldn't go down to 1 qt/lb.

Do you know how much volume is required to fill your pump/ coil? I realize this will vary with tubing length but lets say I keep that very short.

Roughly estimating my system, I have a 1/2" copper manifold that is about 4 feet long, which feeds into my pump, which then goes through about 4 feet of 1/2" silicon tubing, down a 2 foot length of 1/2" copper pipe to my coil (which is about 1/4" inner diameter and 25 feet long), then out another 2 foot length of 1/2" copper pipe back out to another 5 foot piece of silicon hose and returns to my mash tun.

The volume of a cylinder is pi*r*r*h where r is the radius (half the diameter) of the tube and h is the length of the tube in inches.

SO, volumes of each piece:
manifold is "pi * (0.5/2) * (0.5/2) * (4*12)" = 9.4 cubic inches
first hose is "pi * (0.5/2) * (0.5/2) * (4*12)" = 9.4 cubic inches
input leg to coil is "pi * (0.5/2) * (0.5/2) * (2*12)" = 4.7 cubic inches
coil is "pi * (0.25/2) * (0.25/2) * (25*12)" = 14.7 cubic inches
output leg from coil is "pi * (0.5/2) * (0.5/2) * (2*12)" = 4.7 cubic inches
return hose to MLT is "pi * (0.5/2) * (0.5/2) * (5*12)" = 11.8 cubic inches


Grand total of close to 55 cubic inches, which is about 1 quart of total volume.

There is not a lot contained within the pump itself.