Incineration of a test portion at a temperature of 900 °C, until complete disappearance of the carbon in the residue. The method specifies a procedure for the evaluation of natural and added mineral substances together. It applies to contents up to 2 %. It does not apply to hydrolysis products nor to oxidized starches, nor to other products containing more than 0,2 % of chloride. In other cases, see ISO 5809.