After processing, a parchment shell remains on the grains. It protects the grain from external influences but should remove before export. It is a process calling hulling. In the article, we'll tell you how it happens and what is principal to consider.
In the article about the methods of processing coffee, we talked about the three stages of processing that the grain goes through before export and roasting:
- Collection and sorting of berries.
- Any processing of berries: dry, washed, honey, and others.
- Drying of processed grains and hulling.
In this article, we are talking about the third stage - hulling.
What is Hulling
After processing, a parchment shell (patch) remains on the coffee, which reliably protects the beans from external influences. This casing should remove before exporting and roasting coffee.
Hulling is a peeling process in which the parchment shell is removing. If the coffee was processed dry, the whole dried berry is removing during hulling.
In order not to spoil the grains during hulling, you need to take all three conditions:
- Rest immediately after processing. After processing and drying, coffee is placing in warehouses, and orders are awaiting. When the order arrives, the coffee is peeled from the parchment shell and shipped. Typically, coffee rests between one and eight months.
- At the start of processing, the moisture content of the grain is 65%, by the end, it should drop to 10–12%. With such humility, biochemical processes slow down and protect the grains from the loss of trace elements. At a moisture content above 13%, the grains can become moldy. At humidity below 9%, the embryo in the grain dies. It begins to age rapidly.
- The parchment shell protects the grain from the external environment. So that nothing happens to the grain after hulling, it should be packing in grain-pro bags.
How Hulling going
Previously, hulling was doing by hand. Now there are special devices for this - hullers. With the help of friction, they take out the parchment shell.
It is necessary that the huller is well-calibrated and that the beans are not heating in the process. They need to stay chill.
Selection of defects
It remains to check that there are no defects on the grains. At the moment, the most effective way to select defective grains is to do it manually. Without the selection of defects blackened, broken, or sour beans could be found in coffee. One such grain can spoil the taste of an entire cup.
After that, the beans are ready for roasting. They are packed in grain-pro bags and sent to different parts of the world.