Arabica vs robusta, roast levels and processing: what the coffee bag is telling you
TUREFF• •0
A bag of coffee usually tells you three things before you even open it: the species, the roast level and, for speciality coffee, how the beans were processed. Each one shapes the flavour in the cup.
Arabica and robusta
Almost all the coffee in the world comes from two species of plant.
Arabica (Coffea arabica)
- Generally grown at higher altitudes and more delicate to farm.
- Tends to taste sweeter and more complex, with more acidity: fruit, flowers, chocolate, caramel and nuts depending on origin.
- Almost all speciality coffee is arabica.
Robusta (Coffea canephora)
- Hardier, more resistant to disease and heat, and usually grown at lower altitudes.
- Tends to taste stronger, more bitter and earthier, sometimes described as woody or rubbery when low in quality.
- Contains roughly double the caffeine of arabica. Commonly quoted figures are around 1.2–1.5% caffeine by dry weight for arabica and around 2.2–2.7% for robusta, though measurements vary with growing conditions.
- Often used in instant coffee and in some espresso blends, where it adds body, bitterness and a thicker crema. Good-quality robusta exists and is gaining attention.
What roast levels mean
Green coffee beans taste grassy and are hard; roasting turns them brown and develops their flavour. There are no universal rules for naming roast levels, so one roaster's medium can be another's dark, but broadly:
- Light roast: light brown, dry surface. Keeps more of the bean's origin character: brighter acidity, fruit and floral notes. Common for pour-over.
- Medium roast: medium brown, balanced acidity and sweetness, more caramel and chocolate.
- Dark roast: dark brown to nearly black, often with an oily surface. Roasty, smoky, bitter-sweet flavours dominate and the origin character fades.
A common myth is that dark roasts are much stronger in caffeine. The difference between roast levels is small, and the bigger factors are the species (robusta or arabica) and how much coffee you use. "Strong" on a bag usually describes the roasty taste, not caffeine.
Processing methods
After harvest, the seed (the bean) has to be removed from the coffee cherry and dried. How that is done affects the taste.
- Washed (wet) process: the fruit is removed before drying, and the beans are fermented and washed clean. Tends to give a cleaner, brighter cup that shows the origin clearly.
- Natural (dry) process: whole cherries are dried in the sun with the fruit still on, then removed. Tends to give heavier body and fruity, sometimes winey or berry-like flavours.
- Honey process: some of the sticky fruit flesh is left on the bean as it dries. Tends to sit between the two: sweet, with some fruit and more body than washed coffee.
Many producers now also experiment with controlled fermentations, which can create unusual flavours. These are often labelled with words like anaerobic.
Reading a bag in practice
- Single origin means the coffee comes from one country, region or farm, and is usually chosen to show off that place.
- Blend means several coffees mixed for balance or consistency, common for espresso.
- Tasting notes ("cherry, cocoa") describe flavours the roaster finds in the coffee, not added flavourings.
- Roast date matters more than the best-before date for flavour.
Where to start
- If you like bright, fruity coffee, try a light-roast washed or natural arabica.
- If you like a classic, chocolatey cup with milk, try a medium or dark-roast blend.
- If you want more kick, try a blend that includes robusta.
Which species, roast or process do you prefer? Share a coffee you loved, or ask about a term on a bag, in the comments.