As already announced in our previous blog entry about coffee cultivation, we now have a continuation regarding the harvest and the different processing methods.
We already know that each coffee plant only produces its first crops after about three to five years , but it is only after six to eight years that the trees reach their maximum production capacity. Once they reach the age of twenty, the quantity gradually decreases. Various factors, such as soil depletion, plant care, or the health of the tree, influence the decline in the production cycle.
Coffee cultivation - facts about the harvest
In addition, the coffee cherries need a very long time to reach their full ripeness. For Arabica , seven to nine months pass after the flower is fertilized, for Robusta, nine to eleven months , and for rare varieties such as Liberica and Excelsa, even twelve to fourteen months . The ripening process is influenced by factors such as the climate, the soil, and the fertilization.
Normally there is one harvest per year. In tropical regions, which are not only characterized by a clear difference between dry and rainy seasons , there can be two flowering periods per year, which in turn can result in a main and a secondary harvest . Colombia, Kenya and the east of the Democratic Republic of Congo are examples of such exceptions.
The harvest period lasts for ten to twelve weeks . Why is that? Quite simply, not all coffee cherries ripen at the same time. In general, however, the majority of the cherries are ready to be harvested after six to eight weeks.
How are coffee cherries harvested?
We differentiate between three different harvesting methods: picking, stripping and the harvester – each of the three methods has advantages and disadvantages.
Picking
Let's start with the first method: picking, selecting the harvest by hand. Basically, this method is very time-consuming and labor-intensive, but it also guarantees a high level of quality - why is that? Each cherry is picked individually by hand , and only the ripe, deep red cherries are harvested from the branches. However, the selective picking must be repeated every eight to ten days until all of the cherries have been harvested. This harvesting method is used especially for Arabica. One picker can pick a maximum of 50 kg of coffee cherries per day , which yields around 10 kg of green coffee.
Advantages:
– High quality level
– Only ripe and red cherries are harvested
– Harvesting is easily possible on mountain slopes
– Protects the plant
Stripping
The second method is so-called stripping, the unselected harvesting by hand. Here, the cherries are stripped from the branch in one movement , regardless of whether the cherries are already ripe or still ripening. The fruits then fall either directly into a harvest basket attached to the picker's body or onto cloths spread out on the ground. A maximum of 60 to 80 kg of coffee cherries are harvested per picker, which yields around 10 to 15 kg of green coffee.
Advantages:
– Each plant is harvested only once
– Faster harvest than with the picking method
Disadvantages:
– Unripe cherries are harvested
– Small branches and leaves must also be sorted out
Harvesters
The last method is done with the harvester, the mechanical harvest . This requires a special harvesting machine, which can only be used in certain types of terrain and plantations. These machines can usually be used on the large, flat coffee farms in Brazil. The branches of the coffee trees are combed mechanically, ie the trees are shaken with the help of the machine's arm, then the cherries fall into the machine's so-called collector. Up to 200 sacks of 60 kg each can be harvested in a single hour.
Advantages:
– Very large harvest quantity in a short time
– Cheaper than manual methods
Disadvantages:
– Less high-quality green coffee
– Sorting is then necessary
– Machines damage plants
- High purchase price
– Can only be used on flat plantations
What happens after the harvest?
After harvesting, the cherries do not have a long shelf life or can be transported, so rapid processing is necessary.
Depending on the processing of the coffee beans, several steps must be followed depending on the method: harvesting, pre-sorting, pulping, fermenting, drying, peeling and sorting . Basically, we distinguish between four different processing methods: washed, semi-washed, dry (natural) and pulped natural.
Washed processing
In washed processing, the coffee cherries are first pre-sorted after harvesting, which means that the ripe cherries are separated by hand from unripe, overripe or spoiled cherries. Stones, leaves, small branches and all other foreign bodies are also sorted out. The next step is pulping , which separates the cherry pulp from the coffee bean. Grinding discs or rollers made of wood or steel ensure that the pulp is "squeezed off". The distance between the rollers is set so that the bean is not damaged and simply falls through.
The next step is the fermentation of the bean , which is not necessary for every processing. Around the bean there is a so-called pergamino , a covering to protect the bean. These pergaminos are stored in water tanks or basins for twelve to forty-eight hours. The fruit or sugar slime (mucilage) that still clings to the beans after pulping is dissolved by this fermentation process and can then be washed off.
This is followed by drying, where the beans are dried to a residual moisture content of twelve to thirteen percent. The beans are spread out on various surfaces such as concrete, natural stone, asphalt, clay, wood or the so-called African Beds and turned several times during this process. This process takes one to two weeks depending on the weather conditions. The last step is peeling the beans, which separates the parchment and the silver skin from the bean. The beans are then sorted again and packed in sacks, usually 60 kg or 69 kg, and shipped.
Semi-washed processing
In the semi-washed (semi-dry) processing, the cherries are also processed in the same way as washed coffee, but after the pulping, the beans are brushed manually or mechanically with a steel brush. This removes the remaining pulp. In the next step, the coffee is also spread out to dry and turned several times.
Natural processing
Natural (dry) processing is the original processing method, and is particularly preferred in regions with little to no water resources. Cherries that are as ripe as possible are laid out to dry and also turned several times; the drying phase lasts around three to five weeks. The correct degree of dryness is achieved when the shriveled cherry is shaken and the beans inside can be heard. This processing method gives the beans a natural sweetness and a pronounced body.
Pulped Natural Processing
The question remains: what exactly is " pulped natural" ? Just like with dry processing, the cherry is spread out to dry and turned over several times, only the time period is different. Shortly before the cherries become hard, they are pulped. Depending on the color of the pulp residue that is still attached, this is referred to as yellow honey, pink honey or red honey. The darker the color of the pulp residue, the sweeter the taste of the bean afterwards.
Conclusion
As you can see, growing coffee is a science in itself, and you need a lot of knowledge and even more experience from the seed to the green coffee. Be it sowing or harvesting, preparing or processing. That was all just a part of the potential knowledge of growing coffee. Of course you can try it out for yourself, but you should know that coffee is a very delicate plant that naturally only grows at certain latitudes and also needs a very specific climate (which we don't have here in Germany). Trying to create this climate artificially could be very complex. But it's not impossible, so have fun drinking coffee or growing it and #staywild !
