Triple milled soap, also called French milled soap, was created by French soap makers in the 1,700s. First, the soap is formed by a chemical reaction between shea butter and an alkali. After this neutral base soap is created, it is grated into fine particles and passed between a pair of closely spaced rollers, a process called milling, which turns the soap into a paste. During this first milling, fragrances and colorings are added. This milling process helps distribute the color and scent evenly throughout the soap. As you can guess from the name, a triple milled soap goes through this process three times before it is formed into cakes of soap.
The triple milling process produces beautiful bars of soap that are very hard, glossy and smooth. Triple milled soaps also lather well and the bars tend to last longer due to their hardness.