AOAC Official Method 938.06 Fat in Butter
A. Indirect Method
—Final Action
IDF–ISO–AOAC Method
Take up dry butter obtained in moisture determination in which no absorbent was used, 920.116 (see 33.6.03), by macerating with 15 mL absolute ether or petroleum ether; transfer to weighed Gooch or fritted glass crucible (16–40 mm) with aid of wash bottle filled with the solvent; and wash free from fat with 100 mL solvent. (Pass last 25 mL solvent through crucible without suction.) Dry crucible and contents at 100°C to constant weight. Repeat washing with 25 mL solvent and dry to constant weight. Repeat operation until there is no loss in weight due to washing.
Fat, % = 100 - (moisture, % + residue, %)
