All flour is milled at some point. When we talk about fresh milled flour, we mean flour milled at home. Sometimes this is called home-milled flour or home-ground flour, and it's typically used at its peak level of freshness. Freshly milled flour contains higher levels of nutrients and antioxidants. It has a nuttier, earthier taste. Regular (store-bought flour) is lower in nutrients due to its processing and treatment to make it shelf-stable. Most recipes are written for store-bought flour, so learning to bake with fresh-milled flour takes some patience and practice.