Or Heat Exchange Recirculation Mash System.
If you have a pump then you want some way to maintain or raise the
temperatures of your mash.
A coil of tubing is placed into a vessel with water that is heated.
The hot water transfers the heat from the water through the tubing
to the wort as it is pumped through the tubing.
The manifold must not cause the mash to compact and reduce flow.
You need a flow to transfer the heat from the coil to the wort.
Your return must not splash or cause tunneling through the mash.
I made mine from a 20’ coil of ½” OD copper tubing with ½” copper
pipe risers. The finished it off with fittings to adapt it to a hose thread.
Most brewers put bulkhead fittings into their HLT. I wanted the ease
of cleaning so I opted to bring mine out the top of the HLT. In use I
simply place the coil in my HLT and connect the inny and outy hoses.
I just pushed all the parts together without glue. This way
it is easier to take apart and clean. I drilled some 1/8” holes
in the top of the manifold. I use a zip tie to set the depth of
the manifold so it’s just even with the top of the water. This
way the return flow gently mixes back into the mash.
HLT = Hot Liquer Tank a place to heat water for your mash
Wort = Unfermented Beer
A typical session for me is to dough in a few degrees low and with the HLT
10° - 20°F warmer than my desired mash temperature I switch on the pump.
When my desired temperature is reached I simply switch off the pump. While
there is some wort in the tubing that will be higher than the desired mash temperature
it will be minimal. If you hook up your plumbing the way I do you can flush the
coil after each use.