Processing methods
There are different types of coffee processing, each of which will give us a different result and characteristics in the cup, today we are talking about the Washed method.
Given that coffee cherries can be stored for a limited time, they must be processed immediately.
The washed method includes the following steps
- The cherries are washed and sorted in water tanks;
- The pulping allows to separate the pulp from the grain;
- The mucilage attached to the parchment is removed through the fermentation which can last from 8 to 72 hours;
- Washing also known as Channeling: guarantees the complete removal of the mucilage after fermentation and the selection by density of the parchments;
- Dry until humidity level of 12% is reached
Let's deepen some processes starting from the Fermentation before the "Channeling" which aims to remove the mucilage from the parchment, "Remember that the coffee must be washed only with fresh water".
Fermentation in the washing process can take place in two ways:
- When the pulped coffee beans are immersed in water, with a reduction of the initial microbial activity through dilution and cooling and the generation of a controlled anaerobic atmosphere after fermentation in the washing process, the microbial activity must be stopped by washing thoroughly the coffee in fermented parchment.
- When the pulped grains are placed in a tank without adding water, the bottom of the tank will fill with residual mucilage and fluids, generating conditions of low oxygen levels, while the top can allow for oxygen exchange. This leads to increased microbial activity due to higher sugar concentrations and temperatures.
Some of the factors that influence the fermentation are: Time, Temperature, Microbial Colony, Availability of Oxygen, Microbial Activity, which is linked to temperature and microbial concentration.
Drying
The main purpose of drying is to make the beans safe to store and transport. The drying parameters are:
- Time (drying speed)
- Water activity inside the coffee cherries
- Temperature
- Air flux
- Moisture migration
Parchment drying on patio
The maximum thickness of the beans to guarantee a uniform dryer is 2 maximum 4 cm, a further very important procedure for correct drying and not to cause defects in the cup such as mold, dirt and fermented coffee is to stir the coffee often.
Drying on "african beds"
The drying can also take place on the "African Beds" in the sun, including the coffee from the direct sun in the hottest hours to ensure a higher quality in the cup.
Mechanical drying
Drying can also take place mechanically in these cases it is advisable not to exceed 40 degrees in order not to penalize the quality in the cup.
Profile in the cup
The Washed method increases acidity, floral and fruity aromas.