Learn About Coffee
Coffee has a fascinating history and an interesting process from seed to roasted bean. Coffee is the 2nd most traded commodity in the world after oil, with 140 million 60kg bags being produced in 75 counties around the world each year and 2 Billion cups of coffee being consumed each day.
Contents:1. Coffee Cultivation 2. Coffee Beans Preparation 3. Roasting & Blending
With 2 (in the main) types of coffee plant, arabica and robusta, arabica is grown at high altitudes and produces a higher quality bean than robusta, arabica berry’s are hand picked from pure soil which also enjoys pure rain water and produces a heavier crop than robusta which is grown at lower levels. Robusta beans are used mainly blended with quality arabicas or purchased by supermarkets for ground coffee and also used for instant coffee. Coffee beans once harvested are then wet or dry processed which then remove the cherry pulp, ensuring just the green bean remains. Wet processing requires specialist equipment and lots of water, which is not possible in many coffee growing regions. In these regions, dry processing is common which consists laying out the cherry to dry naturally before the outer husk is removed using simpler tools.
Other coffee types such as Liberian, account for less than 1% of global production.
Coffee grows exclusively in tropical climates. The coffee belt around the world comprises of nearly 75 countries which are involved in coffee cultivation and lie between the latitudes of 23 degrees north, 25 degrees south of the equator. The ideal growing conditions for coffee shrubs averages 17°C to 23°C.
There are more than 60 different varieties of coffee, but Arabica and Robusta by far is the most common. Every coffee offers different taste and aroma properties.
Arabica coffee have a particularly fine aroma and are cultivated on plantations at higher altitudes of 650m to 1900m, where lowland coffees (Robusta) have a different flavour and are grown at lower altitudes between sea level and 600m. Both are vital to producing a well balanced espresso blend.
Newly planted coffee seeds take 3-5 years before they produce any coffee. The coffee plant is pruned to around two or three metres, which makes it easy to pick. After five years, it’s ready to produce quality beans – or rather, cherries. These cherries have a little stone in the middle – the green coffee bean, which is the ‘seed of the fruit’.
Harvesting – There are two ways of harvesting coffee:
Selective picking in which the ripe red berries are hand picked. This method is more usual with highland Arabica beans.
Unselective picking in which the farmers wait until 80% of the coffee berries are ripe (red berries) then all the berries are striped from the coffee shrub in one movement, sometimes ustilising equiment but more usually by hand. This means mainly ripe, some overripe and even unripe berries are harvested which can end up with a more irregular quality. This method is more usual with Robusta beans.
Coffee Beans Preparation
Hand picked coffees such as arabica, are usually wet process prepared. This means the coffees are washed, fermented, washed again and then naturally sun dried, which gives a high quality coffee. This process is more labour intensive, therefore more expensive to produce.
The unselective picked coffees are mainly prepared with a dry process (the berries are spread on the floor in the sun) which takes about three weeks. After this process the skins of the berry can be taken off and the coffee can be made ready for export. These beans are then exported to the global markets where the blending and roasting process takes place.
Blending & Roasting
Blending and roasting are key parts in the coffee making process, but there is debate about which should take place first. There can be wide variations in size and density between different coffee beans and they will often roast differently from each other. So if you are experimenting with new coffees then individual roasting before blending is a good way to assess each bean. On the other hand, beans often achieve a harmony in aroma when roasted together. It is also a more straightforward process once you have discovered the blend you want.
There are two key reasons why blending is important. One is to achieve a specific taste, utilising the individual characteristics of beans and mixing them to create a coffee with the desired body, aroma and flavour. A second is to achieve consistency. Batches of beans many vary in taste and quality from month to month. Therefore a blending expertise is required so as to successfully produce the same end result every time, regardless of the harvest.
Roasting is the critical part of coffee making in which the dry green raw coffee beans are physically and chemically transformed. As they are roasted the bitterness of the beans is reduced and the aromas are released, which determines the final flavour. There are a number of different roasting techniques, but the two most common means are by using either a drum or a fluid bed roaster. In drum roasting the beans are tumbled in a rotating drum that is powered by gas or wood. On a fluid bed roaster the beans are roasted as they swirl on a stream of hot air.
The length of time a bean is roasted impacts on its flavour. Lightly roasted beans have a sharper taste, while the darkest roasts produce a heavy, smoky flavour.
Once adequately roasted the coffee beans must be quickly cooled to prevent further cooking. This can be done by either cooling in water, which rapidly drops the temperature, or via normal or forced air, which are slower methods but which result in less weighty beans.
Whichever means of roasting, blending and cooling are adopted, the whole process is something of an art form. Getting the desired taste takes skill and practice.