Anhydrous milkfat is made by removal of practically all of the moisture and nonfat solids from pasteurized cream. The 40% milkfat cream is first concentrated to 70% to 80% milkfat, and then the high-fat cream is processed through a specialized phase inversion unit or separator. The milkfat is further concentrated, with residual moisture removed by vacuum-drying. Anhydrous milkfat contains no less than 99.8% milkfat and not more than 0.10% moisture.

Butter oil is made by the removal of practically all of the moisture and nonfat solids from butter. It is produced by gently heating butter, disrupting the butter emulsion. The milkfat is then concentrated in separators and vacuum-dried to remove residual moisture. Sometimes butter oil is washed with water prior to the final drying stage to remove trace impurities. Butter oil contains about 99.5% milkfat and not more than 0.20% moisture.