Mashing is the process in which your grains' starches are converted to sugar in the all-grain brewing process, which the yeast will then feed off of to create the alcohol content of beer. An insulated vessel used for mashing is called a mash tun, they come in stainless steel or plastic cooler style with an added ball valve and a false bottom, or bazooka screen. A mash tun is a key piece of equipment for the all-grain brewing process. Lautering is a process known as sparging, in which you separate the sugar content from your grains. This can be accomplished using a few different methods, such as using a Hot Liquor Tank (HLT).