The ThermoBarrel is a fully insulated, stainless steel mash tun. For decades brewers have been limited to modified plastic coolers as mash tuns. For those brewers looking for an alternative, there's finally an option. The stainless steel serves several benefits. The foam insulation design gives the tun heat retention comparable or better than most plastic coolers after stabilization. It's long lasting, it prevents any leaching of plastics, and it's easier to clean.