Vietnamese experts skillfully control fire and wind, turning raw green beans into specialty coffee.
Pham Thanh Tung, head roaster at 9 Minutes to Miracle, has been working in the specialty coffee industry for nearly 5 years. In the past 7-8 years, specialty coffee has begun to gain attention in Vietnam, especially among young people.
Tung's work is mainly confined to a roasting workshop of about 40 square meters, while some others will go to farms to work and inspect the quality of imported beans. Coffee beans are labeled "specialty" if they meet certain standards for the number of defective beans and a cupping score of 80-100 according to the standards of the Specialty Coffee Association (SCA).
When imported, the beans are stored in four layers of bags to avoid impact and mold during transportation. The last layer is a standard Grain Pro bag, which is specialized in preserving green coffee beans in the world. The batch roasted on the afternoon of April 17 was 10 kg of coffee from Tram Hanh, Da Lat. Depending on the order, the weight of coffee in each batch is different, but usually Tung roasts about 17 batches per day.
The quality control of specialty coffee is much more stringent than that of traditional coffee. The roastery where Tung works requires farmers to use organic fertilizer from composted coffee husks and animal manure, avoiding chemicals. Every step, from sowing to fertilization, is geared towards sustainability.
Before roasting, Tung will check the moisture content of the beans with a machine. However, thanks to his experience, he can feel it directly with his hands, the reasonable moisture content is around 11-12%. With damp beans, when held in the hand, it will feel a bit cold. At that time, the roaster needs to take some measures to handle it.
To ensure that the beans are well preserved, the temperature in the factory is always maintained at around 20 degrees Celsius.
Before roasting, Tung will have an idea of the "bean profile" in his head, including the roast level, temperature milestones, and control this process with data transmitted from the roaster to the computer.
The custom-made "drum" roaster, priced at about 400 million VND, is a specialized coffee roasting equipment with a rotating drum, ensuring the beans are evenly cooked through heat conduction and convection. Widely used for specialty coffee, it allows roasters to precisely control temperature and flavor.
Parameters such as bean temperature, wind temperature, and air flow are displayed on the control panel. Tung said that there are some automatic roasters, users only need to set the parameters. However, for specialty coffee roasters, they often prioritize manual work to control all factors affecting bean quality.
"Automatic machines can work well in a super-ideal environment," Tung said, adding that just a few small impacts such as a room temperature hotter than normal can cause the machine to suck in hot air, causing excess heat and ruining the roast batch.
The bean testing tube on the roaster helps the worker check the color and aroma changes of the beans at each stage. Tung usually only checks at some important milestones to ensure the roasting batch is on schedule.
With this batch of beans, Tung calculated that the beans would turn yellow at 145 degrees Celsius, and from there, he set a budget for how long it would take to reach that temperature. From there, he would adjust the heat and wind levels to ensure that all reactions during the roasting process took place as planned.
On the computer screen, two colored lines were displayed, showing the wind heat and the bean heat. During the entire process, these two heat lines had to move steadily to ensure a perfect roast. According to Tung, computer software is a great assistant to help every batch of roasting of the same type of bean proceed the same way.
Once roasted, the beans are discharged into the drum below to begin the cooling process.
"Nine minutes is the time for a perfect roast. That's when we get to be in our own world with the fire, the rotation, the focus and all the passion," he said.
The finished product after roasting is evenly colored coffee beans, the aroma fills the small roasting workshop.
Seeds are stored in sealed containers before being packaged and delivered to customers.
Coffee beans can be sold immediately after roasting, but should be allowed to rest before use to achieve the best flavor. This period of time is called degassing - the process of naturally releasing carbon dioxide (CO2) from the coffee beans after roasting.
Before shipping, Tung will check again by cupping and grading according to the SCA global form. Then, he also tests the pour over method to check the quality of the beans. This is a manual method, pouring hot water slowly over the coffee through a filter, but it is Tung's favorite way because it helps to clearly feel the full flavor of the beans.
Tu Nguyen Photo: Hoang Giang