is not suitable for soap making as it may contain more than 10% of unsaponifiable matter. For edible oils, the tolerated limit of unsaponifiable matter is 1.5% (olive, refined soybean), while inferior quality crude or pomace oil could reach 3%. Determination of unsaponifiables involves a saponification step of the sample followed by extraction of the unsaponifiable using an organic solvent (i.e. diethyl ether). Official methods for animal and vegetable fats and oils are described by ASTM D1065 - 18, ISO 3596: 2000 or 18609: 2000, AOCS method Ca 6a-40. Saponification values and unsaponifiables of various oils and fats See also Soapmaking — Small scale process of producing soap References Analytical chemistry