Coffee : Processing

Extraction

Indicates two different processes: extraction of the bean and extraction of the caffeine.

Extraction of the seed is performed in two ways: by dry treatment and by wet treatment.

The caffeine can be extracted via three different methods: a) with water and activated carbon; b) with carbon dioxide c) with dicloromethane and ethylene acetate.

Picking Coffee harvesting method. The cherries are harvested one by one, selecting only the ripe fruit: it is the most expensive technique, but provides the best quality uniform results. The resulting coffee is aromatic, clean and uniform.

Quakers

A term now universally used and applied to coffee beans harvested when still green, damaged or underdeveloped, giving the coffee a flavour similar to peanuts.

Stripping

Coffee harvesting method. Can be done by machine or by hand, stripping the fruit and leaves from the branch. It is quick but damages the plants and the harvest is not uniform. Technically it is simpler and also more environment-friendly; the result is a coffee with higher sugar content.

Roasting

Coffee roasting process. It is performed in a fluid bed or in drum roasters. The heat from the walls and from the other beans causes the green raw beans to bounce, tumble and crack, like pop corn.

Dry processing

This system produces natural coffee, when the beans are harvested by stripping. It consists of the following phases: cleaning and washing (separation from leaves, twigs and debris), drying (in the sun or in dryers – 1-3 days / 45-60°C); hulling (separation of skin/pergamino from bean); winnowing (the beans are sieved using screens with sized holes).

Wet processing

This system produces washed coffee and is used in particular if the coffee cherries have been harvested by picking. It consists of the following stages: cleaning, pulping (mechanical separation of pulp/bean via rollers); fermentation (12/24 hours in water to remove the mucilage); washing (120 l/kg); drying in the sun for 9-10 days or in a dryer; hulling and polishing; winnowing. The process affects the final colour of the bean: Coffea Arabica becomes blue-green, Coffea Robusta becomes green-yellow.