When selecting coffee beans, ensuring the quality of raw coffee sources by eliminating beans with unsatisfactory factors.
Mold particles, perforated worms, white beans, black beans, dried fruits,..., are the factors that need to be removed.
This is a very important stage to experience the quintessential, completely natural aroma of coffee.
During this stage, the beans are dried to help the coffee beans evaporate. First, heat the roasting drum in the range of 170-220°C and then fill the drum with green beans. The temperature is reducing greatly at the same time will increase to 10-15°C/min ( relatively fast ).
This stage will end when the drum temperature reaches 155-160°C. The coffee beans now turned from green to yellow.
This stage is divided into 2 stages:
1. After being dried, coffee beans always begin to move the cleavage metabolic stage to create intermidates and precursors for browning. This step raises the temperature to about 5-10°C/min. The coffee beans gradually changes from yellow to darker yellow.
2. This stage is extremely important in the aroma of coffee beans. The beans has sugar and amino acids, so the coffee beans turn brown because of the caramel reaction. Smoke the roasting machine is now rising. The temperature in the drum is now around 185-200°C.
On this stage depends on the tastes, preferences and preparation of each indiviual that finishes the roasting process.
For robusta beans, coffee beans will roasted and end about 30-45s after the second explosion, failling between 227-230°C.
After the coffee is roasted and satisfactory, the temperature is still very high. Leaving coffee at such high temperature for too long will lose its aroma affecting the quality of coffee beans. Before grinding, certain coffee beans must be incubated in a dry place for at least 5 days to stabilize the aroma.
Preserving in a cool, dry place, avoid places with high humidity and places without odors.
Very hot or cold temperatures will reduce the aroma typical of coffee.