Recirculating mash tun - manifold or false bottom?

[The_Bishop]

I'm building a system similar to the 'brew easy' Blichmann is coming out with, with constant recirculation between the boil kettle and mash tun, adding heat as needed to the kettle which then gets pumped to the mash tun in a recirculating loop.

I've got the system mostly figured out, except for the bottom of the mash tun. Should I go with a false bottom, or is a manifold ok? I've read so many threads about the pro/con of each that my head is spinning. Cost wise, a custom false bottom is damn near the cost of a Bayou kettle *with* a false bottom.

The mash tun is an 8.5 gallon stainless kettle.

I had settled on a manifold made out of PEX, originally. I am now second guessing that.

This is the manifold I made:

Here it is in the mash tun:

Would this work with a recirculating rig? Or am I better off with a false bottom?

This setup should work like the Blichmann easybrew; 1/2 the water in the mash tun, 1/2 the water in the boil kettle. Water is pumped from the outlet of the boil kettle up to the mash tun, where the level will be controlled with an autosparge. Water flows through the grainbed, out of the tun, and gravity drains back to the boil kettle, where it starts all over again.

I'm concerned about the recirculation part of using the manifold. I haven't been able to find anyone recirculating a mash tun with a manifold, and I'm thinking there's probably a reason for that.

Can I use a domed false bottom, like this?

It's 12" in diameter. My tun is 14.5" in diameter with a flat bottom, so there will be a space of 1.25" between the edge of the false bottom and the tun wall. As long as it's held firmly against the bottom of the tun, would this work?

 

[The_Bishop]

As a follow up:

I decided to order the 12" domed false bottom. My plan is to install it with hard tubing and compression fittings, so it's firmly held in place in the mash tun.

 

[acidrain]

Good choice. My feeling is the bigger the area, the less dead spots.

 

[The_Bishop]

I hope so. Should show up tomorrow.

 

[davelkin]

Will you be able to clean it if it is hard plumbed? Or do you intend to use super strong chemicals to CIP?

I am planning a copper manifold without solder so that I can disasemble and clean it. Also I found that cutting slits halfway through the pipe using a jig saw allows for good flow and no sticking. The slits make sense to me because they are similar to the blichman false bottom that has those circular openings.

I agree that it seems that the pin hole type false bottoms are very popular.

 

[The_Bishop]

I'm planning on using flare fittings, probably copper tubing to run from the valve to the false bottom. Still hard piped, but able to be disassembled for cleaning. Once I have all the pieces in front of me I'll figure something out.

The reason I'm trying to get away from the manifold is I'm planning on recirculating and I'm not convinced a manifold is up to the task as far as flow goes.

 

[pvault98]

Will you be able to clean it if it is hard plumbed? Or do you intend to use super strong chemicals to CIP?

I am planning a copper manifold without solder so that I can disasemble and clean it. Also I found that cutting slits halfway through the pipe using a jig saw allows for good flow and no sticking. The slits make sense to me because they are similar to the blichman false bottom that has those circular openings.

I agree that it seems that the pin hole type false bottoms are very popular.

This is exactly what I made for my 10 Gallon rubbermaid cooler. Mine is a square with a cross piece in the middle. I have a T on one end to connect to the spigot and it works perfectly and is easy to disassemble after each brew for cleaning. I regularly get 73% efficiency and could get higher if I lautered slower, but this is the sweet spot for me. It prob took an hour to build and just a few dollars worth of copper.