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Methods for ash are based on the fact that elements and to some extent minerals are not destroyed by heating, and that volatility is low.

The three steps involved in the ashing procedure are briefly described below:

1. Sample preparation: a homogeneous (representative) dried sample (2-10 gram) has to be used for the determination of ash. The ’fresh’ material is in general first cut, dried and/or de-fatted. The reason for this is that moisture and fat in the sample may lead to spattering during the ashing procedure, which on it’s turn may result in sample loss.

2. Heating of the sample -usually held in a porcelain crucible- in a muffle furnace at 500-600 °C for 12-24 hours.

3. Weighing of the residue in the crucible (=ash).

| Determination of ash in food is important for at least two reasons: 1. To verify whether the sum of organic material (protein, available carbohydrates, fat, water, fibre) + inorganic material (ash) adds up to 100% of the total weight of a food. 2. To calculate carbohydrate content by difference (see case on carbohydrates and fibres). |

Ash is a mixture of elements and minerals obtained after extensive heating of a dry food sample