ASTM D1981-11(2015)

1.1 This test method covers the measurement of the Gardner color of tall oil fatty acids after heating in an atmosphere of nitrogen at 205°C for one or two hours, depending on whether its iodine value is over or under 15, respectively. The specimen may be heated using either an aluminum heating block or an oil bath. This method is applicable to all tall oil fatty acids. Applicability of this method to other types of fatty acids has not been determined.