A mash tun is a vessel used in the brewing process, specifically for converting starches from grains into fermentable sugars. During mashing, crushed grains, often malted barley, are mixed with hot water in the mash tun. This process activates enzymes that break down the starches, creating a sugary liquid called wort. After mashing, the wort is separated from the solid grain husks, typically using a method called lautering. The wort is then transferred to a kettle for boiling, where hops are added. The mash tun is a crucial component in the production of beer, influencing the flavor and quality of the final product.