6 April 2020

Cacao: The fruit behind your chocolate bar

Find out where cacao comes from, how we grow it at Kew, and how it's made into the sweet treat we know and love.

By Ellen McHale

Cacao princess of wales conservatory

Chocolate has become part of our daily lives. We turn to it when we're celebrating, commiserating, or in need of a mood boost.

Find out about the amazing fruit behind our favourite treat. 

Where does cacao grow? 

Cacao (Theobroma Cacao) is native to South America and is cultivated in many countries that have tropical climates, such as Ghana, Indonesia and Nigeria. 

Cacao trees thrive in areas with high humidity and rainfall, and grow best in the shade. 

Eaten by humans for more than 5,000 years, these yellow fruits were originally cultivated by indigenous people in South and Central America. 

It's thought that the Mayans ground up cacao beans and mixed them with chilli to make a spicy drink, and the Aztecs were so enamoured with cacao that they they used it as currency.

Cacao pod growing in the Princess of Wales Conservatory
Cacao, Ellen McHale © RBG Kew

From bean to bar 

Cacao is the essential ingredient in our chocolate bars, but it goes through lots of processes before it reaches our local shops.

When cacao fruits are ripe, they're harvested and split open to reveal the beans inside. They're tightly packed and surrounded by white, jelly-like flesh. 

The beans are fermented to develop the flavour, and then dried, roasted and ground up to make chocolate. 

They are ground by a mill to create a thick brown liquid known as 'cocoa liquor'. This is the basis of all chocolate products, and is mixed with ingredients like sugar and milk to create different types of chocolate. 

Cacao pods being opened
Cacao, Unsplash/Rodrigo Flores
Empty cacao pods
Empty cacao pods, Rodrigo Flores/Unsplash
Dried cacao beans
Dried cacao beans, Pablo Merchan/Unsplash

An unusual plant 

Most plants flower by growing new shoots, but cacao trees are unusual.

They produce flowers from their trunks, and they flower best on wood that is more than three years old. This unusual botanical trait is called cauliflory. 

Each flower usually only lasts a day. At Kew, the flowers are carefully hand pollinated by our horticulturalists. 

In the wild, the tiny flowers are pollinated by small flies like midges.  

Cacao flowers
Cacao flowers, W.H. Stuppy © RBG Kew

Valuable wild cacao

Cacao is a valuable plant and growing wild cacao can be a good way for local people to diversify their incomes in tropical regions.  

Kew scientists have worked with communities in Bolivia to grow wild cacao to support their livelihoods.

This is part of a wider project to restore abandoned cattle pasture in the Amazon. Growing native trees will improve soil fertility in these damaged areas and allow crops to be grown in the restored soil.  

This hopefully will encourage more sustainable management of soils and forest in the region, whilst also supporting local livelihoods. 

Cacao at Kew 

We currently have six cacao trees growing in the Palm House and the Princess of Wales Conservatory, grown from a single seedling donated in the 1980s. 

Our largest tree grows in the Princess of Wales Conservatory. It loves all the light in this glasshouse and fruits successfully twice a year. 

Cacao, Ellen McHale © RBG Kew
Cacao, Ellen McHale © RBG Kew

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