(Click for the original, Dutch, version of this article)
“Read the labels on anything you buy and DO NOT BUY ANYTHING CONTAINING GUM ARABIC!” cautioned an anonymous pamphlet that circulated the internet in 2001. In the wake of the terrorist attacks on 11 September of that year, a British newspaper had discovered that terrorist organisation Al-Qaeda was trading gum arabic from Sudan. Anyone boycotting the substance helped prevent the terrorists getting richer – easy, right?

Except that you had to read every label, and for good reason. The gum, often disguised as E414 on lists of ingredients, is actually found in all sorts of products. It does not have any taste or fragrance; it doesn’t clot and seems to improve whatever you add it to.

If it has any effect on our health at all - studies are inconclusive - it’s a beneficial one. You could eat or drink unlimited amounts of it if you wanted to. Used as an emulsifier, it ensures that soft drinks, ink and salad dressing don’t revert back to their various components. As a thickening agent, it gives ice-cream a pleasant consistency. It’s the “glue” on cigarette paper, it sticks the coloured coating to M&Ms, it’s in cosmetics, vegetarian meat substitutes, insecticides, medicines and sweets, including the better types of traditional Dutch liquorice.

Manna

Gum arabic, the “manna” from the Bible and Quran, is tree distress solidified. It is not terribly difficult to grow the relevant tree varieties on a plantation: they would grow faster and be conveniently close together, but they would produce much less gum. They need drought, the lashes of the desert wind, plant disease and gnawing insects. Only then will the tree excrete a thick, yellow substance: the tears of the acacia.

Unlike resin, the gum can be dissolved in water. When it is fresh from the tree, it is soft and malleable but will harden later, turning into a kind of golden, semi-translucent crystal. Apple and cherry trees also produce gum when they are distressed, but that kind is far less suitable for most industries.

The gum itself cannot be reproduced and its properties are difficult to copy too. In her book Gum Arabic, Leiden University anthropologist Dorrit van Dalen narrates how a sweets manufacturer from Zeeland used the substance to coat sweets, and one day discovered that it did not stick to the sweets anymore. He had been using the same bags of gum from the same tree variety from the same region and the contents looked the same, but despite that, it could hardly be used to make sweets. After a few years, the gum worked just as well as it had previously, but neither the sweets manufacturer nor the gum supplier could explain why.

Gum Arabic tells the cultural history of the acacia tears and describes Van Dalen’s quest to discover the story behind it. It is published by Leiden University Press, the university publisher, but don’t let that to put you off. It is a translated, updated version of an earlier Dutch version published by Bert Bakker.

That means that the book is not a tough, academic treatise but a reader-friendly book for a large audience. In fact, if we had any criticism at all, it would be that very little is mentioned about the gum’s biochemistry, despite its huge importance, compared to its history. The composition of the gum crystals is explained briefly, and only in the very last chapter that could almost have “appendix” written over it.
To be fair, the history is a great yarn. The rags for Egyptian mummies were soaked in dissolved gum, Pliny the Elder described how, in Ancient Rome, perfume was made with gum. Monks in monasteries copied their books using ink based on gum and gall. For a long time, the trade was in the hands of the Arabs – which is why it’s called gum Arabic – but by the fifteenth century, Europeans had a foothold in Africa. Now, they could negotiate with the “Moors”, although there was a risk of being taken prisoner and sold as a slave.

In the eighteenth century, gum arabic proved indispensable for printing bright patterns on cotton, and everyone wanted cotton in bright patterns. The price of gum skyrocketed, France prohibited the sale of it to the non-French, and in England the fabric printers begged their government to intervene and control the prices. The French and the British fought long wars, with frigates, canon and sly diplomacy, for access to the gum market. Whoever had that access would be as rich as Croesus: in a good year, the French Compagnie sold their gum on the markets of Paris and London for thirty times more than they had paid for it.

In short, this stuff was worth a fortune. And still is: so far, it cannot really be imitated and some of the most modern industries in the world are almost entirely dependent on the Acacia trees that grow wild in the Sahel, and the willingness of the local people to pick the gum of the trees. If they were to go on strike, or if a swarm of locusts were to destroy the harvest, the price would rise to five or six times its normal price and there would be nothing any soft-drink manufacturer could do about it. Today, the boycott called for in the angry 2001 pamphlets is still unthinkable.

Gum Arabic tells the story of a product that everyone consumes, perhaps daily, without realising it; it is a fantastic tale of explorers, hot, steamy African countries, politics, religion, riches and power. Read it and you’ll never look at your bottle of coke in the same way again.

Dorrit van Dalen
Gum Arabic – The golden tears of the acacia tree.
Leiden University Press, 203 pages € 24.50