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V. RESULT AND DISCUSSION
A. OBSERVATION OF MANUFACTURING PROCESS 1. Processing of Instant Coffee
From observation made during the internship in the Panjang factory, basically the processing of coffee from raw materials into an instant coffee powder includes 5 steps,
namely roasting, grinding, extraction, evaporation, and spray drying.
a. Roasting
Before roasting, green coffee should through the tipping process. Tipping process aims to move the coffee beans from the bag into the silo. It also aims to clean
the coffee beans from impurities that present in the sack. Coffee that is received from suppliers is placed into the holes tipping. The bottom of the holes tipping is
connected with a screw conveyor which functions to transfer the coffee beans to the bottom of bucket elevators. Bucket elevators will lift the coffee beans to the destoner.
Outlet section of the bucket elevator is connected to the inlet of destoner.
In the destoner there is a separation between green coffee with other materials such as dust, metal, and wood. After out of destoner, beans are blown to the
silo using a blower. In this stage, the green coffee is roasted in order to remove H
2
O and CO
2,
optimizing aroma, and increase size and color. The concept of roasting is flow the air with high temperatures on the outer surface of rotary drum. The green coffee that will
be roasted is inside the rotary drum. When the desired color is achieved, roasted coffee is rapidly cooled using water to stop the roasting process.
Figure 1. Roasting coffee in rotary drum The functions of roasting are:
1. The flavor formation.
During roasting, there is a chemical process that result flavor components. The longer of roasting process the more flavor components will be resulted. But
this process must be limited to avoid unwanted flavor components formed.
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The color and texture formation. During roasting, CO2 and water vapor were resulted in the coffee beans.
The pressure in the coffee beans will increase and make it became bigger. Water vapor and CO2 will out from coffee beans gradually but there are some vapor
will stay in the roasted coffee. Besides, the color of coffee beans will change became dark.
3. Extractability
Under and over roasting will reduce extractability, because coffee beans that being undercooked or burnt cannot be extracted well.
b. Grinding
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