Cocoa beans are the starting point of a chocolate. Raw cocoa beans are cleaned and then ground to make cocoa liquor (cocoa mass), cocoa butter and cocoa cake (which is further milled to make cocoa powder). These cocoa products form the basic inputs of chocolate.
The quality of input cocoa beans is a very big determinant of the final taste of the chocolate. The quality of input cocoa beans also determines the yield of different cocoa intermediate products, thereby directly impacting the profitability of the cocoa bean processor.
Cocoa is an agricultural commodity. Its quality depends on many factors. Some of them are:
- The type or variety of cocoa tree from where the cocoa beans come
- The age of the plantation
- Climatic conditions at the time of flowering and maturing of cocoa pods
- Fermentation conditions on the cocoa plantation
- Handling and logistics of the cocoa beans from production zone to the consumption factory
All these factors are controlled and managed by different people. Often, their motivation, in managing the quality of the cocoa may not be in line with those of the final consumer of the cocoa beans – the processing factory. It is thus critical for the buyer of cocoa to ensure that the cocoa beans she is buying conform to the quality norms she needs.
How can one determine the quality of cocoa beans?
In almost all cases, when cocoa beans are traded, their quality is specified in the contract between the buyer and seller. The quality depends on physical and chemical characteristics of cocoa beans. It is the responsibility of the cocoa beans suppliers to assure that the agreed quality will be supplied to the buyer.
Federation of Cocoa Commerce (FCC) is one of the most widely followed industry body of the cocoa industry. It has laid out rules regarding sampling and determination of cocoa quality. Going into the details of each sampling and testing rule is beyond the scope of this article. But we will cover the important quality parameters, what they mean and a brief about how they are tested.
FCC has set a benchmark for quality. But the buyer and seller are free to add or modify the quality parameters that they agree on. In all circumstances, the final agreed upon quality parameters should be mentioned very clearly on a legally binding contract.
So, what are the quality parameters for cocoa beans?
When cocoa is traded in many metric tonnes, we need to prepare a representative sample. This sample, drawn randomly from the cocoa beans in question is deemed to represent the quality of the parcel of cocoa. FCC stipulates precise sampling rules to ensure a representative sample is created while economizing on the size of the sample to reduce wastage.
Once the sample is created, it is measured for its physical and chemical properties. One set of physical properties are determined by inspection of the cocoa beans and the other set is determined by cutting open sample cocoa beans (called the cut test) to examine the interiors of the cotyledons. Chemical properties are measured by chemical analysis of the cocoa.
The physical properties measured by examining the beans are:
- Humidity – this refers to the percentage of water content in the cocoa bean. It should be less than 8% for export grade cocoa beans.
- Bean count – the average number of beans in 100 gram of cocoa. For main crop cocoa it should be 100 or less. The lesser the bean count, the better as it ensures that beans are larger and there is more nib in the bean than shell.
- Sievings – the sample is sieved through a screen of 5 mm diameter holes. The quantity that passes through the sieve is weighed and expressed as a percentage of the weight of the sample. FCC allows sievings to be at 1.5%.
- Cocoa related matter – these are clusters of cocoa beans (2 or more beans sticking together), broken beans and associated fragments and pieces of shell which do not pass through the sieve. These are sorted and their weight expressed as a percentage of the total weight of the sample. FCC allows 3.5% of cocoa related matter.
- Flat beans – these are beans which do not have nib in them. It is a bean that is too thin to be cut to reveal the complete surface of the cotyledons. FCC allows a limit of 1.5%
- Foreign matter – this is any foreign substance other than cocoa beans, cocoa related matter, flat beans and sievings. It is allowed at 0.75%
To expose the internal quality of the cocoa beans, a certain number of cocoa beans are cut open. The beans are split into half using a blade or a “guillotine box” and its interiors examined. The following physical characteristics are determined by the cut test:
- Mouldy Bean – this is a cocoa bean that has been infested by mould. One can see fine threadlike mould formation when the bean is cut open.
- Slaty Bean – this is a bean not properly fermented. Its cotyledons appear slatish grey in colour.
- Violet or Purple Bean – this is a cocoa bean where the cotyledons exposed by the cut test are of a violet or purple colour.
The most important chemical property of cocoa beans is the percentage of free fatty acids. Free fatty acids are undesirable to chocolate makers and many want them to be less than 2% in cocoa beans. Free fatty acids are an optional quality parameter of the FCC contract. It is determined by titrating a sample of butter extracted from the cocoa bean against a base (normally potassium hydroxide or KOH) with phenolphthalein as the indicator.
As you have seen, cocoa beans have many quality parameters. It is of critical importance that as a buyer of cocoa beans, one is aware of the quality one is buying.