Cacao pod and seeds.

Feves de cacao by Rog01 on Flickr is licensed under CC BY-SA 2.0.

How Chocolate Works: The Science of Cacao Production in Peru

Part two of our sustainable chocolate series looks at the science behind cacao cultivation – and how it becomes the chocolate we love so much.

The basics of cacao production are fairly straightforward, but a healthy crop requires specific conditions to flourish and balancing all of the contributing factors can get pretty complex.

High-quality, rich, aromatic chocolate is produced from proper cultivation techniques that farmers have been sharing for centuries. With 90 per cent of Peru’s cacao production being organic, working closely with nature is a must for a hale and hearty yield.

The basics of cacao production are fairly straightforward, but a healthy crop requires specific conditions to flourish and balancing all of the contributing factors can get pretty complex.

High-quality, rich, aromatic chocolate is produced from proper cultivation techniques that farmers have been sharing for centuries. With 90 per cent of Peru’s cacao production being organic, working closely with nature is a must for a hale and hearty yield.

Cacao trees are evergreen trees that thrive in tropical rainforests. High temperatures (30°C), high humidity (up to 100 per cent), and regular rainfall (1,000-3,000 mm annually) allow the tree to grow as high as 8 metres, producing flowers and fruits. The fruits, also known as pods, produce seeds – an average of 30-60 per pod – that once harvested, fermented and dried, are then ground into the chocolate so many of us cannot resist.

For the most sustainable and profitable results, farmers plant cacao seedlings in a well-shaded and plant-inhabited area, preferably among established fruit trees like banana, coconut and papaya. The shade acts as protection from high UV rays that limit growing potential by causing sun damage, soil drought and weeds. This is one of the key strategies for environmental sustainability and organic production as it keeps surrounding vegetation intact and maintains crop health without the need of harsh chemicals to ward off pests and disease.

After about three years, the trees bear fruit, sprouting 15 to 30 centimetre brown, yellow or red pods out of the branches and trunk. Farmers harvest each pod one by one with a machete. One week after harvesting, the pods are carefully opened to retrieve the seeds from the surrounding mucilaginous pulp.

The seeds are then fermented in wooden boxes. Covered by banana leaves to retain moisture, the seeds are left in the “sweatboxes” for 2 to 6 days to complete the anaerobic and aerobic phases of fermentation. Micro-organisms turn the sugar from the mucilage pulp remnants into alcohol and then acetic acid. The heat produced from fermentation raises the temperature of the boxes to 45°C and the seeds are moved regularly to maintain optimal oxygen levels for the biochemical reactions that create the famous flavour and aroma of chocolate.

After fermentation, the seeds are left in the sun to dry, reducing their moisture content from approximately 60 per cent to under 10 per cent. The precise conditions of the fermenting and drying process influence the chocolate’s acidity and bitterness.

When unnatural practices interfere with nature’s process of cacao production, quality is lost. Examples of this include using chemicals to speed up fermentation or using machines instead of the sun to dry the seeds. Maintaining natural cultivation methods is essential to creating not only the most ecologically sustainable chocolate, but the best-tasting as well.

Be on the lookout for new cacao developments occurring at agricultural research institutes, such as new bio-control strategies to prevent disease, instead of using harsh chemicals. Santiago Gomez Bernave, a master’s student working on his thesis at the Institute for Tropical Crops in Tarapoto, Peru is also exploring exciting innovations such as exotic-fruit infusions at the fermentation stage of cacao seeds to enrich the flavour and aroma of the resulting chocolate. Products like raw nibs and cacao liquor are also being improved with science, providing naturally-enhanced flavours – and new consumer addictions!

Daniella Quarrey is completing her Bachelor of Environmental Studies in International Development and Bachelor of Arts in Spanish and Latin American Studies at the University of Waterloo this semester. She is currently living in the Amazon jungle working at the Peruvian Amazon Research Institute helping foster sustainable development for cacao and coffee crops as a research assistant for bio-protection of tropical crops.