Yesterday we made some progress on our new mash tun. The basic idea was to construct the mash tun out of two buckets, a 50-litre food grade inner bucket and a 65L cheaper outer bucket. We installed 1/2″ stainless steel fittings between the two bottoms (including a PT100 temperature sensor) and added in a sheet of styrofoam for increased stability and insulation. The inner bucket is now drainable from the bottom. We then filled the space between the two buckets with polyurethane foam for stability and insulation, and left it to dry overnight. We still have to construct a false bottom, which we will make from a stainless steel kettle lid. The lid will get hundreds of 2-3 mm holes drilled through it and stainless steel feet installed on it. We also have plans for buying and installing a Blichmann AutoSparge in the mash tun, to prevent overflowing and allow for a more automated mashing process.
Here is the inner bucket before any modifications.
Drilling a hole for the stainless steel fittings.
Shortening the through-hole fitting with a Dremel.
Testing for leakage.
Fittings installed and styrofoam sheet being cut.
Buckets fitted and tap installed.
Filling with polyurethane foam.