Cleaning the cocoa beans
Let's make a clean job of it.
When the cocoa beans finish their long journey by ship from the countries where they are grown, they are transported to the chocolate factories.
On arrival, they contain not only dust and sand but often also large foreign bodies such as stones, wood or jute fibres. These impurities must be removed fully before processing, partly to protect the processing machines, but mainly to maintain quality. Otherwise, unpleasant aromas could be created when the cocoa beans are roasted, which would be transferred to the cocoa beans and spoil its aroma and taste.
In the cocoa precleaning unit, the cocoa beans go through several sieving stages: a coarse sieve, a fine sieve, a strong flow of air (aspiration), a metal separator (magnet) and a vibratory sieve remove leaves, fibres, sand, stones and metal from the cocoa beans. Now the cocoa beans have been cleaned of impurities.
The fermentation and drying processes also contaminate the cocoa beans with micro-organisms, most of which are entirely harmless. These micro-organisms are killed, either during roasting or beforehand by means of sterilisation. This involves treating the cocoa beans with high-pressure steam; the heat and moisture is an extremely effective means of killing off the micro-organisms which live mainly on the outside of the shell.
One positive side effect is that some of the moisture lodges between the shell and the kernel. When the cocoa beans are subsequently roasted, this moisture evaporates and the shell is easier to separate from the kernel. Now the cocoa beans can safely go on to the next processing step to make chocolate.