There are two main types of coffee- Arabica (which most of us know) and Canephora. Arabica is about 2/3 of world production and Canephora is the rest. Robusta, belongs to the Canephora family. It is more resistant to diseases and grown at lower altitudes than Arabica. It also has about twice the caffeine of Arabica.
Arabica does have more complex aromas and is more expensive than Robusta.
Seeds are germinated (called matchsticks as that is what they look like); they then grow a pair of rounded leaves- the first and only leaves – hereafter the first pointy leaves appear and the plant is planted into small bags for a few months for further development. The bush grows and is most productive in its 3rd year, production decreases towards the 5th year when the bush is completely cut, about 30cm from the soil. It then lets out new shoots and the process begins again. Each planting can have up to 5 of these cycles (25 years) before the plant is no longer productive, gets gut at the base and burned.
The shrub produces flowers (then seeds) when it is most stress i.e. when there is least water. In this region this is in January, and thus the largest harvest is in October (9 months later). There is a mini harvest in April/May after a drier period in July. However, in between there are fluctuations in rainfall and thus the shrubs flower and seed fairly continuously and thus coffee is picked daily.
This process is entirely by hand. There are approximately 70 permanent workers on the farm and at peak picking this goes up to 500! Pickers are paid per kilogram.
There are two types of drying processes:
- Dry process where the whole fruit is dried (seed, peel and muselage)
- Wet process where the peel and muselage is removed first. Dry only the seeds. This company uses the wet process.
The processing steps are as follows:
- The fruits that are picked daily are transported to the sorting and washing plant.
- Fruit that has borers, or air bubbles floats and the better quality sinks.
- The fruit is peeled to remove the skin and muselage, and the beans then pass a strainer that will only allow peeled beans through due to size, unpeeled green fruit will be processed differently.
- Various tanks are available for splitting the beans into: 1st (sinking of the sinking beans) 2nd (floats of the sinking beans) and 3rd (floats of the floating beans) class.
- Two stages of drying occur to get the moisture to 10-12%.
- Export beans are stored in 40kg bags, parchment around the beans is only removed just before export or roasting. This parchment is also used as fuel for the drying ovens.
- The beans are then sorted by density- lower density beans contain contaminants such as hollow beans and parchment, while higher density beans are best quality –less contaminants.
- The beans are then sorted by size (cause size matters J ) Both monster beans and tiny beans are a problem because they burn easily when roasted, and are thus low grade. The best are medium sized beans.
Coffee beans that are going to be exported will go off site to be sorted electronically, then bagged for export, 70kg bags to all countries except Canada who takes their coffee in 45kg bags- the joke was that Canadians aren’t as strong as Colombians.
Export bags contain information on the producer /country number (alphabetical order)
Exporter number and shipment number.
The process of roasting beans is of course most important and is when the flavours and aromas are developed.
The higher the temperature and longer you roast a bean for the more you will hide the flavours-good and bad. This is thus done with 3rd grade beans.
The lower the roasting temperature the fuller the subtle aromas and flavours.
Low temperatures, for a long time bake the bean and produce very dull coffee, while too high a temperature for a short time will only burn the outside. Beans that are the same colour thus do not necessarily have the same taste as their colour could have been attained by many paths.
When beans are roasted the internal temperature of the roaster actually decreases a little as moisture is released, before increasing again. Medium roast coffee- in my opinion – the best way to have 1st grade beans- is the point between what is called the first and second crack. The coffee beans make a popcorn type crackling sound at first crack and like an electric current sound at second crack.
Two interesting facts:
Caffeine is broken down at 239C, coffee is not roasted to this temperature and thus the caffeine content of lightly roasted and dark roasted beans is the same. Thus it would be incorrect to refer to coffee as being “caffeine” strong based on its roast, rather than its taste alone perhaps.
Coffee beans are best about 1 week after roasting. For this time period the beans release carbon dioxide and flavours develop. This release of gas is also the reason why some producers make coffee bags for shop sale with valves installed- to release this CO2- not for us to smell it really. The bags that do not have valves are sometimes found to be inflated in the shops- this is due to this gas release.
