The Grinder, one of the first structures that are unlocked by the players as they gain experience, is described to be a stone bowl or basket with a wooden stick inside of its area that will be used to grind up or mush certain materials or vegetation, specifically harvested Barley.
The Grinder's only uses as of March 19, 2018, is to mush and grind up Barley into an edible food source known as the Grain Mush. When clicking on the Grinder without an equipped tool, a GUI pop-up screen will appear on the player's screen that will enable the player's ability to grind up barley and other materials in the near future.
Afterward, the players have the option to consume it, if it is a food item, store it in the player's chests, or to be cooked and/or used with other structures to become products, like the Campfire.
The Grinder's crafting recipe lists that it will need 3 Stones, as well as 1 Stick. It is noted that it only has 25 health, making it easy for raiders to pillage and destroy player's homes and/or bases and will become a rubble of its former self. Once fully destroyed, the Grinder will drop 1-3 Stones.