THE PRIMADONNA OF CROPS @museum.de

Coffee plants are very demanding, which is why they’re sometimes dubbed the "primadonna" of crops. They need a tropical or subtropical climate and a specific altitude – which means that growing and harvesting the crop takes a great deal of effort.

Even now, growing coffee generally requires manual labour, and in many countries the crop is still grown by small farmers. Millions of people all over the world are involved in coffee farming.

Today, 124 different coffee varieties are known. However, most aren’t suitable for cultivation and consumption. Only four coffee species are commercially grown. You already know about Arabica and Robusta, but two others, called Liberica and Excelsa, are also cultivated in very small quantities.

There are not only species of coffee, but different strains produced by breeding, such as Bourbon, Caturra or Gesha.

On plantations, the coffee trees are pruned to a height of two metres – roughly six foot six. They start fruiting after about three years.

Even with careful tending, it takes seven years for a coffee tree to produce a full crop: about 500 grammes of finished roasted coffee per tree and per year – barely eighteen ounces. To produce good quality coffee, you need to harvest several times, because the fruits don’t all ripen at once. So most coffee is harvested by hand.

The use of harvesting machines is only feasible on large, flat areas. Some plantations in, say, Brazil and Australia fall into that category.