Stone milling is a simple affair. The wheat berries are milled between two stones—a stationary stone on the bottom and a rotating stone on top, each cut with milling patterns that dissipate toward the outer perimeter of the stone. When dropped into the mill, the wheat berries (made up of 3 components - endosperm, bran, germ) are thoroughly crushed, with the germ oils expressed and integrated into the endosperm. Straight from the mill and into the bag it goes! The resulting flour may then be sifted (or “bolted”) to remove a portion of the bran. But, the flavorful germ remains.In Roller milling, the 3 main components of the wheat are separated: bran, endosperm, and germ. First, wheat is hydrated with water to “temper” the grains. This toughens the bran layer and causes it to fracture into larger pieces that are easier to remove in the sifting process. The berries then go through the roller mill, a series of cylindrical rollers that rotate towards each other at very high speeds, shattering the berries. The resulting material is then sifted, separating the three main components. The endosperm is then milled and sifted again to make white flour. Many roller-milled “whole wheat” formulations then re-introduce the bran, but not the germ, as oils in the germ are not considered shelf-stable for the long periods that flour may sit on a supermarket shelf.