After reading about homemade homebrew equipment in an issue of Zymurgy, I was inspired to make a false lid for my cooler mash tun in order to hold the mash temp better. I used inch- thick polystyrene insulation (start argument about leaching chemicals now), wrapped it in foil and punched my analog thermometer through the top. Used it twice so far and the mash temp in a pre-heated cooler held for an hour. I had been lusting after a SS mash tun but not anymore. I love the tips I get from that magazine and other home brewers!