Methods of coffee harvesting: Selective vs Strip


Methods of coffee harvesting

Selective vs Strip

Coffee quality is defined by many factors, such as coffee variety, terroir, processing methods, warehousing and harvest method. The last one here surely is a very important moment that defines the quality of the coffee in the cup. Probably majority of us is keener to manual selective harvesting, that also has a stronger tradition. However, the decision what harvesting method the growers will choose depends on desired coffee quality, the availability and cost of the workforce, topography, available post-harvest equipment. Here, we will shortly describe the two methods and their advantages and disadvantages.

Selective Harvesting

Known also as cherry picking. To reach the highest complexity of coffee in the cup, it is essential that the cherries are perfectly mature when they are picked. When we want to select only perfectly ripe coffee fruit, they must be harvested by hand. The pickers spend the day picking ripe fruit and filling their baskets, that is periodically being emptied into a larger bag. A good picker harvests from 4 to 8 jute bags of fruit per day, that after being dried gives from 30 to 60 kg of green coffee. Especially in the mountains, when maturing is spread through longer period, pickers can pass each coffee tree five or even ten times to ensure the cherries are picked at the right time. And every time, they leave unripe cherries on the tree for next harvesting. Overripe cherries are also picked and kept separate from the ripe fruit. In Brazil we call them passa.

 

Selective Harvesting advantages:

Selective Harvesting disadvantages:

Strip Harvesting

A greater part of the world’s coffee is harvested practicing this approach as it is faster and more economic. Using this approach, all the fruits are picked off the trees at same time. While this method is much more efficient, it also results that harvested coffee is a mixture of cherries with different maturation stage. And that adds to astringency and significantly lowers the cup quality. Using high-quality postharvest equipment such as pulpers and optical sorters can reasonably resolve this problem during further processing. Strip harvesting can be performed at least three different ways.

Manual Stripping

As already the name says, this method is done completely manual. It starts with putting the nylon under the row of coffee trees. Next. step is grabbing the branches one by one and pulling it onwards, kicking all of the coffee cherries onto the nylon. After doing this with all the coffee trees alongside the nylon, the pickers collect the coffee into bags and move to another row of trees.

Mechanical Stripping

Like in the manual stripping, this approach also starts with placing the nylon under the coffee trees. But the physical picking of cherries is done with help of mechanical strippers. Some kind of a prolonged hands with vibrating fingers, that knock all of the coffee cherries from the trees onto the nylon. The accumulated coffee cherries are then put into bags. This method is quite unkind to the coffee trees. As such, some modernized and gentler equipment similar to olive harvester equipment have been introduced.

Mechanical Harvesters

This type of harvesting requires very flat areas. It is performed using a mechanical harvester that was in the beginning of the seventies and is maybe most similar to a corn harvester. It uses trembling and rotating mallets to knock the coffee cherries into collection units. The modern harvesters nowadays have some possibilities to minimize the yield of unripe cherries. Such as setting the speed of the machine and adjusting the roatation nad trembling mallets. Another approach is removing the bottom mallets at the first harvest, as the coffee on the upper part of the tree usually matures faster. In next harvest, the lower mallets are usually added to harvest, so the lower part of the plant can be harvested.

Strip Harvesting advantages:

 

Strip Harvesting disadvantages: