Processing coffee

A coffee plant blooms several times a year and can also have flowers and ripe fruit. It has beautiful white flowers. The fruit of the coffee plant is a berry that contains two or more coffee beans. The ripe fruit are dark red to purple. The plant can grow up to 13m, depending on the variety. The first harvest can be made after two or three years.

Coffee Cherries

The fruit of the coffee plant is a fleshy cherry, which hides the coffee beans. Each bean is still wrapped in pulp. The peeled beans are green and surprisingly do not smell. Coffee obtains all its aromas and tastes after being roasted. Green beans come in various shapes and sizes. It depends on the variety of coffee plant and also the area where the coffee grows.

Coffee Picking

Ripe beans are picked from coffee plants in various ways. The first is manual picking, which requires a lot of time and money, but the result is really high-quality coffee. Only really ripe beans are picked from the coffee plant and the plant is not damaged. Another method is stripping, when a whole branch is taken and everything on it is removed. The fruit are often damaged and this destroys the plant itself. The last method is by machine, where a plantation uses a special machine that removes absolutely everything from the coffee plant. This is what damages the plant the most. Coffee picking accounts for the largest part of the amount upon sale.

The collected coffee beans have to be removed from the skin they have on the surface. Coffee beans have three layers of wrapping and one layer of pulp, which surrounds each double and single bean. There are two ways of processing coffee, when the various layers of the skin are separated from the bean itself. They are dry processing and wet processing. Both methods have an influence on quality, but also the price of the coffee.

Dry Processing

Dry processing is used on lower-quality beans. This method is used primarily in Central America, Brazil and Arabia. The picked coffee cherries are placed evenly on the ground, mostly on concrete floors. There they are left to dry for approximately one month. They have to be regularly turned over and raked, in order to get rid of all the moisture. This also prevents the cherries from fermenting. The fruits are affected by the air and sun, making the outer skin of coffee beans go brown. They are fragile and the beans rattle inside them. This method is less expensive, but great care has to be taken to ensure that the fruit does not go dry and that it finishes drying.

Wet Processing

Wet processing is a more expensive method. The advantage of it is that it much more perfectly separates the unripe and damaged beans from the rest of the beans. Better quality beans undergo wet processing. This is why arabica is sometimes called “washed” coffee. In contrast to dry processing, when using this method it is necessary to remove the seed vessel immediately after harvesting, within no more than 24 hours. The skin is much harder to remove later and the beans could be damaged. The separated beans are washed in water, which separates the poor-quality and unripe beans. The green coffee is then left to ferment in tanks. Fermentation can take 36 hours. The beans are then dried the same way as in dry processing.

Both methods have a big influence on the taste of coffee. Dry-processed coffee is more chocolate, whereas wet-processed coffee has more marked flowery and fruity tones.

After processing the coffee is sorted by quality and size and packaged in 60kg jute sacks. It is then distributed around the world, mostly by ship. The best-known ports in Europe include Hamburg and Trieste.

Coffee is then sold by individual variety. Lots of varieties, sizes and qualities can be chosen. The green beans then undergo another important process, roasting.

Roasting

Roasting is a very important process during which the coffee beans obtain their resulting flavour and aroma. If you picked up a couple of green beans, you would find that they are very hard and do not smell of coffee at all. Green coffee is poured into a roaster and kept spinning round in a large drum, so that all the coffee is roasted equally.

What happens during the process? The beans increase in size and fall in weight – the water in them evaporates. The roasting temperature is around 200–240°C; each roasting plant chooses the temperature itself. The length of roasting is always at least 15 minutes. How long we roast coffee for, the degree of roasting as it is known, primarily influences the flavour of the coffee. A light roast gives are more marked, sour taste. When coffee is roasted for longer, to a medium degree, chocolate tones are obtained. Longer, darker roasting leads to a more marked bitter taste.

After roasting coffee has to be left to de-gas, because various gases are still working and leaving it. The varieties are then blended, or coffee goes to customers as a single variety. Blends have the advantage that their flavour is much more complex and finer. Varieties always have a specific, standout taste.

(Author: Petra Veselá, photo: Oxalis, spol. s r. o.)