Mash Tun

      A mash tun is the vessel where crush grains, or grist, are combined with hot water to form sweet wort. The process of mashing converts the complex starches in the grains into sugar which will then be turned into alcohol by the yeast during fermentation. A good mash tun will be well insulated as a stable temperature is key. Most homebrewers use coolers like mine because they are cheap and insulate well. In order to separate the grains from the liquid, false bottoms or screens are installed. Below are some images of the mash tun used by Skull Stache Brew.

I replaced the spout with a ball valve on a Coleman cooler.

Attached to the ball valve on the inside is a tee. The two ends of the tee are connected to a stainless steel mesh with a coil of stainless steel wire on the inside to make it ridged and prevent the grains from crushing it. This mesh will filter the wort as it is pumped out.

On the outside of the lid is a camlock connected to a pipe and tee on the inside. During circulation of the RIMS system, the return will flow through the top and be dispersed by the tee on top of the grain bed. It is important to allow the liquid to fall on top of the grains and not straight through to the bottom.

This is what it looks like when it is filled with the grist.

Once filled with liquid, the mashing process begins.

Here are a few links to other pages on how to build your own mash tun with different types of coolers.

http://www.youtube.com/watch?v=ftY_HZAFJFc
http://www.homebrewtalk.com/wiki/index.php/Converting_a_cooler_to_a_mash_tun