Cacao-Chocolate value chain – Part 1 Cacao

The process of making artisan chocolate is at least a 12 step process, with half of the steps done by the cacao farmers and producers, and the remaining steps done by the chocolate makers. This is the first article in a two part series, of which this covers the cacao farming and production steps.

Cacao (Theobroma Cacao) is a tropical crop and grows in a narrow geographical band about 15 to 20 degrees north and south of the Equator. The fruit of the cacao tree is the cacao pod, inside the cacao pod are cacao seeds surrounded by a sweet white pulp or mucilage. This pulp is delicious by itself. The seeds go through a number of steps to become dry cacao beans, which is the product used by chocolate makers to produce chocolate.

Much of the cacao grown in the South Pacific is by smallholder farmers, who grow it as a cash crop. There are numerous documents written on the state of Cacao production in the South Pacific, including these by Australian/NZ aid program PHAMA.

The cacao product that is exported to chocolate producers is the dry cacao bean or cocoa bean. Note in this article the terms cacao and cocoa are used interchangeably.

The main steps followed by the cacao farmer/producer are:

Cacao varietals are a complex topic. For much of the 20th century it was believed that there were only 3 main genetic varieties – Criollo, Trinitario and Forastero. The seminal work by Juan Motamayor in 2008 classified cacao into 10 genetic clusters. The USDA-ARS (Agricultural Research Service) added an additional cluster and use some slightly different names as per the table below.

Cacao varietals have different characteristics which can have an impact on pod and bean appearance, flavour, yield, resilience to pests, diseases and environment changes. In the Pacific, there are very few areas which are planted with just a single varietal.

Farm Management relates to the various farming activities related to growing cacao, such as Integrated Pest and Disease Management (IPDM), pruning, weeding, grafting, growing seedlings. These activities have an impact on managing pests and diseases as well as yield, ease of harvesting and bean size.

Pod harvesting is done when the cacao pods are ready to be harvested. It is much easier to harvest if the trees are kept to a manageable height at 3m or less. In the Pacific the pods are cut from the tree using a long handled hook or a machete. Once they are harvested, the pods must be broken with a blunt tool such as a stick to remove the seeds and pulp for fermentation.

Cacao fermentation is a scientifically complex activity in which the seeds and pulp undergo an aerobic and anaerobic fermentation process for up to 6 or 7 days. It is undertaken to kill the seeds and stop them germinating, as well as to initiate the chemical changes for flavour development of chocolate. The following image describes the microbiology of the fermentation process.

Source: ACIAR HORT/2014/078 VARTC Fermentation Trial (Box, Pit and Tray) 29Nov-08Dec17

The most common fermentation method in the Pacific is box fermentation. In other countries heap or pit fermentation is common, A newer technique starting to gain some popularity is tray fermentation. With box fermentation, the seeds and pulp mass are placed into a wooden box, usually lined with banana leaves and covered with hessian sack and then left to ferment. The fermenting pile is turned each day to ensure uniformity and avoid cold spots, usually by moving into a neighbouring box. In a system with 6 boxes, this means that there can be 5 boxes used with one spare. The fermentation can reach 50 degrees Celsius as outlined in this temperature chart of various fermentation techniques. The increased changes in temperature occur shortly after the turning and aerating of the fermenting mass.

Source: ACIAR HORT/2014/078 VARTC Fermentation Trial (Box, Pit and Tray) 29Nov-08Dec17

A standard box fermentation in the Pacific.

Each day of fermentation, the internal appearance and characteristics of the beans undergo changes and the farmers undertake cut tests daily to evaluate the progress of fermentation. It is common to see the following poster or similar with cocoa fermentaries / driers in the Pacific. Progress of fermentation can change due to environmental conditions or poor turning techniques or cacao varietals, however for the majority of Pacific cacao, day 6 is typically when the beans have finished fermenting.

Drying – once the beans have finished fermenting, then they are ready for drying. In many parts of the world cacao beans are dried in the sun. However in the Pacific this can be problematic due to the regular rainfall and high humidity which is commonly over 70%. For many years in the Pacific, cocoa beans have been dried using wood fired driers that use wood or coconut shells as the source such as the Kukum drier. This will typically take 3 days of constant drying and is not only environmentally unfriendly by burning firewood for 3 days, but is also unhealthy for the workers who stand on the drying platforms above the smoky fires raking the beans, and also contaminates the beans with smoke.

A later design that was developed for the Pacific is the solar drying house. This is a small house frame with drying racks covered by UV resistant plastic that protects the cocoa from rain and is also designed to enable airflow to draw in through the bottom of the house and out a vent in the roof.

Cocoa solar drier in Makira, Solomon Islands

The solar drying house is a good design but does not work effectively during consecutive days of overcast or rainy weather.

The most effective drier in the Pacific that produces premium quality beans and can operate in any weather conditions is the Grainpro Solar Bubble Drier. The drying beans are placed in a long plastic enclosure that has a zipper along the full length of the enclosure. Fans run at one end of the enclosure over the cocoa beans with the moist air exiting out of a vent at the other end of the enclosure. The fans are powered from a deep cycle battery which is charged by solar energy collected by solar PV panels.

The beans can take between 4 to 10 days to dry using either the solar drying house or bubble drier. The aim is to get the beans down to between 6.5% and 7.5% MC (Moisture Content). Higher than 7.5% and there is a risk of mould growth during storage and transport. Less than 6.5% and the beans can become brittle and separate into nibs, which is not preferred by chocolate makers who are usually roasting the whole beans and want consistency with the roasting.

Storage and transport – once the beans are dried to the optimum MC, then they are stored until ready for transport for export. There is high risk of bean spoilage during storage and transport due to smoke contamination, rain or seawater which causes moulds, or pest infestations such as cocoa moths. For all our cocoa, we insist on Grainpro hermetic storage bags which prevents and protects against all these risks.