The Mash Tun is the starting step in making various types of alcohols. Adding grain and water, you can create a mash which must then be fermented. It is a part of the brewing process.
As an example, a brewer could choose to make Whiskey. This process requires you to make a grain mash, then you need to ferment it, distill it and then age the product to get Whiskey as an output consumable.
Markeplace Listing: Here
Energy Consumption: 10
Tool Requirement: None