Large wooden mortars and pestles have been used to hull grain in West Africa for centuries. When enslaved Africans were brought to the Americas, they carried this technology—and knowledge of how to use it—with them. During the Middle Passage, some slave ships carried un-hulled rice, and enslaved African women were tasked with using mortars and pestles to prepare it for consumption. In both colonial North and South America, rice continued to be primarily milled by hand in this way until around the mid 1700s when mechanical mills became more widespread.