Harvesting, processing and preserving coffee.

Harvesting, processing and preservation are important steps that affect the quality of green coffee products when exported. Many farmers have been growing coffee for a long time but have not yet performed these steps properly.

The first requirement for harvesting coffee is to pick at the right ripeness. To have high quality coffee, it is necessary to have red or medium ripe berries, not to pick green berries. Do not leave rotten or dry berries on the tree. If there are any of these types mixed in, they need to be dried separately.

In the harvested product, the percentage of ripe or medium ripe berries is at most 95%, except for the last harvest, the percentage may be lower.

Pick coffee by using your fingers to pick the berries, do not strip the branches, do not pick the whole bunch for Arabica coffee. Must protect branches, leaves, buds to avoid affecting the next crop. Do not let coffee berries mix with the soil, which can easily be infected with fungi and diseases.

Coffee must be processed immediately after picking. If not in time, spread the coffee beans on a cool brick floor, not more than 30 – 40 cm thick. Do not incubate the coffee beans to make them hot and ferment. Do not keep the picked coffee for more than 24 hours.

The packaging of fresh coffee beans and the means of transport must be clean, without the smell of fertilizers, chemicals, etc.

Processing and preserving rice coffee.

There are two processing methods: dry processing and wet processing. For tea coffee, most of them use the wet processing method and a part of the Robusta coffee is also processed using the wet (or semi-wet) method if requested by the customer.

For Robusta coffee in the Central Highlands, because the harvest season is usually the dry season, people apply dry processing to take advantage of solar energy.

Wet processing: After picking, the coffee must be selected separately from the green and dry beans, and the fallen branches and leaves, dirt and rocks, etc. The ripe coffee beans are put into a fresh husking machine to separate the bean shell. Coffee beans with the husk removed, and the husk is called parchment coffee.

Parchment coffee must have the outer layer of the husk removed. That is the soaking and washing stage. Therefore, people call this method wet processing. And coffee processed by this method is “washed coffee”.

Parchment coffee has the outer layer of the husk removed and is washed clean, which is wet parchment coffee. This coffee is dried and has a moisture content of less than 10 – 12%, which is called dried parchment coffee.

If fresh fruit coffee is the raw material (input) of the wet processing process, then the dried parchment coffee product is the output of this process.

Dried parchment coffee goes through the process of dry milling, removing the husk, polishing (removing the silk skin stuck on the outside of the coffee bean) to obtain green coffee. Green coffee is also classified to become commercial coffee for trading.

Dry processing: Coffee berries are brought back without being milled fresh but are dried until the moisture content drops to 12 – 13%. Usually, a batch of dried coffee takes 25 – 30 days. Put the dried coffee into milling with a dry coffee milling machine, remove the fruit shell, dry husk, and we get the finished coffee bean.

In addition to the two methods above, in our country, the semi-wet processing method is often applied. In this method, people mill the coffee berries fresh with a fresh milling machine, remove some of the slime, then dry them, do not ferment them, and wash them completely.

Treating wastewater and coffee berries during processing: In many places, wastewater from processing factories has stagnated, causing foul odors and polluting the environment.

According to the results of the research on sustainable coffee development methods of the PPP project, people can collect wastewater and treat it. Waste during processing should be used to compost organic fertilizer or put into a gas digester.

Prevent mold formation and OTA (Ochratoxyn A) toxin contamination, and practice food hygiene and safety.

The main content of this issue is to limit coffee contamination through the harvesting and processing stage. Do not let coffee berries or parchment coffee come into direct contact with sand or in places near waste such as animal manure, sewers, etc.

Finished coffee put into storage must be dried to a moisture content of 11-12% and not allowed to become wet again. Reduce the percentage of impurities in finished coffee to the lowest level, not exceeding 0.5%.

Collected.