Paragraph 5 PROCEDURE

Place each test sample of 70 (± 5) grams into an Erlenmeyer flask which is then closed with a stopper. Place the flask in the 50°C water bath for 2 hours, then transfer to the 25°C bath for a further 2 hours. Transfer the flask back into 50°C water bath for a further 2 hours and then return to the 25°C bath. Maintain the water in each bath at constant temperature, stir fairly rapidly and ensure that the water level is above the level of the sample in the flask. Protect the stopper from condensation by a rubber cap or aluminium foil.

After two thermal cycles, keep the sample at 20 ± 3°C for the determination of the oil retention value.