Advertisement
Food

How to understand the pull of coffee

Wake up and smell the beans

After a morning in one of southwestern Ethiopia’s dense cloud forests, I returned to Bonga for lunch – and another coffee. With a pair of forest guides and a local forager, I had been slogging through the wet undergrowth among tall, skinny wild Arabica coffee trees – the source of that beloved hit of caffeine that was firing the sensors of my central nervous system.

These trees were the wild ancestors of Arabica (Coffea arabica), one of the two main species of coffee cultivated today. The other species is Robusta (Coffea canephora), with its natural distribution in the lowlands of West and Central Africa. Reaching 35ft in height, the Robusta tree is larger than its Arabica counterpart, and can grow in lower and more humid elevations. It is a hardier plant, with a high tolerance for a devastating fungus called coffee leaf rust and again many pests. Robusta also gives a stronger jolt of caffeine. Perhaps part of its tropical durability derives from that caffeine content, nearly double thatof Arabica.

Our attraction to caffeine is clear. Less so is why caffeine was so important in nature. Among recent studies, the 2014 sequencing of the Robusta gene by a large international group of scientists has shed some light on how enzymes involved in making caffeine evolved. There are a handful of theories to explain why caffeine developed in coffee and other plants like tea, cacao, and the South American yerba mate plant, and all may be correct.

One theory is that caffeine, which accumulates in the leaves, acts as a pesticide that repels insects and deters herbivores. High doses of caffeine can be toxic for insects, and so their taste receptors have evolved so that they avoid it. We see a similar response when babies refuse green vegetables such as broccoli – in nature, a bitter taste is often a sign of poison.

A second theory argues that caffeinated plants are allelopathic, meaning they try to inhibit the growth of other species. When the leaves fall, the caffeine leaches into the soil and contaminates it, limiting, stunting, or even killing off competing species.

I prefer a third theory. The plants produce nectar so that insects will spread their pollen. Lacing it with low doses of caffeine might be a way to get them to remember the flower’s scent, encouraging pollinators to return and spread the pollen. This, in turn, diversifies the species even further.

Advertisement
Advertisement

Perhaps remembering the buzz, they keep coming back for more—just like people.

“Another coffee?” the woman in the Bonga restaurant asked, taking the empty cup from the table. Even though it was already the fourth of the day and not yet two o’clock, most definitely yes!

Where The Wild Coffee Grows (Bloomsbury) by Jeff Koehler is out now

Advertisement

Bigger Issues need bigger solutions

Big Issue Group is creating new solutions through enterprise to unlock opportunities for the 14.5 million people living in poverty to earn, learn and thrive. Big Issue Group brings together our media and investment initiatives as well as a diverse and pioneering range of new solutions, all of which aim to dismantle poverty by creating opportunity. Learn how you can change lives today.

Recommended for you

Read All
Tom Kerridge and Marcus Rashford's cheap and low energy recipe for tortilla pizzas
Summer survival guide

Tom Kerridge and Marcus Rashford's cheap and low energy recipe for tortilla pizzas

Tom Kerridge and Marcus Rashford's easy and cheap recipe for rainbow halloumi couscous
Summer survival guide

Tom Kerridge and Marcus Rashford's easy and cheap recipe for rainbow halloumi couscous

Tom Kerridge and Marcus Rashford's healthy and affordable recipe for turkey burgers
Summer survival guide

Tom Kerridge and Marcus Rashford's healthy and affordable recipe for turkey burgers

Tom Kerridge and Marcus Rashford's cheap and simple recipe for carrot and courgette spaghetti
Summer survival guide

Tom Kerridge and Marcus Rashford's cheap and simple recipe for carrot and courgette spaghetti

Most Popular

Read All
How much will the Queen's funeral cost?
1.

How much will the Queen's funeral cost?

The internet's best reactions as Kwasi Kwarteng cuts taxes and lifts the cap on bankers' bonuses
2.

The internet's best reactions as Kwasi Kwarteng cuts taxes and lifts the cap on bankers' bonuses

From benefit claimants to bankers: Here’s what the mini-budget means for your pay packet
3.

From benefit claimants to bankers: Here’s what the mini-budget means for your pay packet

5 ways anti-homeless architecture is used to exclude people from public spaces
4.

5 ways anti-homeless architecture is used to exclude people from public spaces

To mark our new Arctic Monkeys exclusive interview, we’ve picked out some of our best band and musician interviews from the past, featuring Arctic Monkeys (2018), When Jarvis met Bowie, The Specials, Debbie Harry and more. Sign up to our mailing list to receive your free digital copy.