Determination of the calorific value of food stuffs

Principle

In order to determine the heating capacities of commercially available solid fuels (coal, coke, lignite, peat, etc), pieces weighing 0.5 to 1 g are used. Wood and peat have to be air-dried, and coal and lignite have to be stored under dry conditions.
In order to determine the calorific values of solid foodstuffs (bread, meat, cooked egg white, etc), samples of the respective "dry matter" weighing 0.5 to 1 g are used. To determine the heating values of gases (natural gas, ethane, propane, butane, etc), it takes 500 ml of that gas, which is stored in a gasometer. The substances to be analysed are burned in stream of oxygen with excess oxygen in order to ensure complete combustion.
Solid materials are placed in the combustion chamber of the calorimeter insert on a thermally insulated base and ignited by means of an ignition source (combustion lance with butane cartridge). The oxygen is supplied via a combustion lance.
To burn the gases, the combustion lance is inserted deep into the combustion chamber of the calorimeter insert. The heating values and calorific values can be calculated from the amount of the substance burned and the amount of heat, which is released in the reaction and measured with the calorimeter.

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