Pick up a bag of coffee in a UK supermarket and the label usually says "arabica", "robusta", or nothing at all. That one word tells you a lot about what you are about to drink, how it was grown and why it costs what it does.
Two species, two very different coffees
Almost all the coffee we drink comes from two species. Arabica is the more delicate, slower growing plant. Robusta is the hardy one. Arabica thrives at altitude, where cooler conditions slow ripening and give the cherry longer to build sugars and aromatic compounds. Robusta is easier to farm, gives a higher yield and copes with lower altitudes and more pests.
The difference shows up in the bean itself:
Caffeine. Robusta contains roughly double the caffeine of arabica, which also adds to its bitterness.
Sugar and oils. Arabica carries more sugar and more lipids, which is why it tends to taste sweeter and fruitier, with a rounder, richer mouthfeel.
Bitterness. Robusta is higher in chlorogenic acids, which add astringency and an earthy, woody bite.
Arabica makes up a little over half of the world's coffee, and it is generally more expensive, because it is harder to grow and yields less.
What this means for coffee snobs
Arabica is the species coffee experts tend to prefer, because it can produce a huge range of flavour, from floral and fruity to chocolatey and caramel sweet. Specialty coffee, graded 80 or above on the SCA scale, is arabica.
But it is worth being fair. Robusta has a role, and a fine quality robusta can taste better than a poor arabica. Italian espresso blends have traditionally included some robusta, partly for body and a thick crema. So "100% arabica" is not a guarantee of quality by itself. The grade, the farm, the roast and the freshness matter just as much.
How Britain ended up drinking robusta
Britain was a tea drinking nation before the war. Instant coffee changed that. Nescafé launched in 1938, American troops spread it during the Second World War, and after the war it was exported to the UK. Within a few years British coffee sales were far higher than before the war.
The catch was the bean. Instant coffee in Britain in the 1940s and 1950s was commonly made with cheaper robusta rather than arabica, and it was often bitter and stale. Many people had little to compare it with, so they adjusted to the taste. Britain never looked back. Today around 80% of UK households buy instant coffee for home.
The economics were simple. Robusta is cheaper to grow and mature, so blending it with arabica brings the price down while keeping body and crema, a common recipe being around 80% arabica and 20% robusta. For manufacturers and caterers serving millions of cups, that kept coffee affordable and commercially viable. For drinkers, it meant a generation grew up thinking coffee simply tasted bitter.
Later, brands began offering instant made with 100% arabica, a sign of how much expectations had changed.
What to check for when you buy coffee
- The species. Look for "100% arabica" on the label. If it does not say so, the coffee may contain robusta.
- The grade. A cupping score tells you how the coffee was assessed. Specialty starts at 80.
- The origin. Region, farm or producer. The more specific, the more traceable.
- The roast date. This matters more than a best before date.
- Whole bean or ground. Ground coffee goes stale far faster.
How coffee needs to be stored
Four things spoil coffee: oxygen, light, heat and moisture. Keep it in an airtight, opaque container, away from the kettle, the oven and sunny windowsills. Roasted coffee tastes best in the first few weeks after roasting, once it has finished releasing gas but still holds its aroma. One way valve bags let that gas escape without letting air in, which is why good bags have them.
Do not keep your everyday coffee in the fridge. Moisture and strong food smells will damage it. Buy what you will use within a few weeks, and grind just before brewing if you can.
Where we stand
At Siren Grounds, we believe you should always know what is in your cup. Our range is built on specialty South American arabica, cupped at 81 and above on the SCA scale, and we are open about where it comes from.
Good coffee is not about snobbery. It is about knowing what you are drinking and why it tastes the way it does.