While a working knowledge of the coffee tree might not be essential to enjoying an espresso, there are a number of reasons why reading into its botany can heighten your coffee-drinking experience. Understanding the coffee plant can help you recognise and appreciate the diversity of flavours and varieties available, which will strive in different environments.
The coffee plant’s botanical name is Coffea. Within the Coffea genus, there are a number of different species. Coffea arabica (Arabica) and Coffea canephora (Robusta) are the two main and most distinctive. Arabica produces the most desirable and complex flavours. Therefore, it accounts for some 60-70% of the world’s coffee. It is, however, more susceptible to damage from frost and diseases than other species.
Robusta – which is as its name suggests, hardy and more willing to grow in easily accessible or harsher places – is highly desirable for the amount of caffeine in the beans. Robusta happens to naturally contain some 30-40% more caffeine than the Arabica. Because its taste is stronger, earthier, and more naturally full-bodied, it’s commonly used in Italian-style blends, usually for espresso. Lately, there’s been a lot of development in the processing of Robusta making it sweeter than it used to be.
The coffee tree itself, no matter the species, is fairly easy to spot. Its ridged, waxy, dark-green leaves make it distinctive even without its fruit. The same is true of its small clusters of short-lived flowers. These have a strong, sweet scent, and look somewhere between lilies and jasmine with their long, slender white petals and stamens. A little-known fact is that the leaves and flowers of the coffee tree also contain caffeine – which, botanically speaking, is a naturally occurring toxin intended to prevent the plant being devastated by hungry wildlife – and are sometimes used to produce tea.
In the right environment, the coffee plant can grow to well over 10 feet tall and produce fruit for decades. The amount it will produce, and the quantity and quality of the fruit, will depend on the ‘terroir’; everything about the plant’s production from the soil’s pH, the altitude, air temperature and amount of rainfall, all the way through to farming practices.
A healthy coffee tree will take about 3-4 years to start producing fruits, or ‘cherries’. There is great variation in colour of the fruits from bright-red or deep-purple, to yellow when ripe. Inside, surrounded by wet, slimy pulp, are two seeds – although a small handful contains only one, which is known as ‘peaberries’. The little seeds may not look like much, but they become what we recognise as coffee beans once they’ve been processed and roasted.
Different types of coffee tree will produce fruit with different qualities. Just as with most fruit with varieties, such as apples, the appearance of a coffee cherry is a good indicator of flavour. Different colours and shapes, to those who know their coffee cherries, can even be indicative of a certain flavour profile – just as a Cox apple will be reliably sweet, and a green apple reliably sour.
There are too many variables beyond the natural properties of coffee, and too many thousands of cultivated varieties of the plant, for any coffee to be recognisable by its taste alone. However, for most people (and experts) it’s enough to take the time to explore different coffees, identify the flavour profiles they like, and to seek out those coffees that are grown and produced with those characteristics in mind. Farmers will usually be looking mostly for varietals resistant to pest and diseases, while coffee buyers will more interested in looking for unique flavours. It’s very important that both work together in order for us to enjoy the best beans.
A knowledge of the general botany of the plant can be a good place to start and will help a coffee lover find out which coffees, grown in which origins, they like best – and why.