- French milled soap begins with crystals made from previously manufactured soap. The crystals go through a pair of stainless steel rollers known as a French mill.
- The milling process turns the mixture into a fine paste and makes the soap mixture smooth and homogeneous. It also removes glycerin, which would stick to the rollers.
- The French milling process ensures that each bar is consistent in color, fragrance and texture. True French milled soap is factory-made.
- Rebatching, or hand milling, is the handmade equivalent of French milled soap. Soap makers melt shredded or diced soap pieces in a liquid and pour the mixture into molds to harden.
- French milled soap is sometimes called "triple milled" because the soap mixture passes through the steel rollers at least three times before it is molded into bars or cakes.
