3.2.2. Shell percentage

Manufacturers require the shell to be loose enough to be easily removed during processing, but strong enough to remain unbroken under normal handling. The shell should also be free of adherent matter such as lumps of dried pulp, which are liable to interfere with the separation of nibs from shell. 

The shell of main crop West African cocoa beans normally makes up 11-12% of the total bean weight, a norm against which other cocoas are judged. Higher shell percentages mean less edible material and hence a lower value, although offering more protection to the nib. 

The shape of the seed and thickness of the seed coat varies with the type of cacao grown, and this together with varying post-harvest practices affect the shell weight.

Careful de-shelling is required as a first step in the production of edible cocoa products, especially since the shell is often the most contaminated part of the bean, for example for microbes (including moulds), PAH, OTA and some pesticide residues. 

The Codex Standard for Cocoa Mass and Cocoa Cake (CAC CXS 141-1983 Rev 2025) specifies that the shell and germ must be less than 5% m/m of the cocoa mass (cocoa liquor) calculated on the fat-free dry matter or not more than 1.75% calculated on an alkali free basis (for Cocoa Shell only). 

For cocoa cake, the shell and germ should not be more than 5% m/m calculated on the fat-free dry matter, or not more than 4.5% calculated on an alkali free basis (for Cocoa Shell only). Shell % in cocoa products can be estimated using a method based on the analysis of fatty acid tryptamides.