22 2.
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
Before entering the extraction process, roasted coffee should be broken down into smaller size as needed. The tool used to break up the roasted coffee is grinder.
Grinder used is a kind of multistage. Grinding process also aims to remove the epidermis of the seed. The particles from grinding process are usually referred to
roast and ground coffee.
The size of roast and ground coffee can be divided into three kinds, namely coarse, medium, and fine. Coffee that is too large cause the longer extraction process,
therefore there is the standard size used an extraction process that is effective and efficient.
Figure 2. Grinding coffee processing
c. Extraction
After roasted and grinding, extraction is a part in the instant coffee production on a large scale. This stage aims to take a soluble solid and flavor component. The
definition of the extraction itself is a process of transferring dissolved solids in the liquid solution form.
In this process a transfer of soluble solid from roasts and ground coffee in liquid form use certain pressure and temperature. It is similar to the process of
brewing coffee that we often do at home. If a roast and ground coffee put in a hot
23 water, the hot water from the coffee will drive solid through the pores of roast and
ground coffee. Then we will get the coffee extract. Aqueous solutions produced at the extraction process called liquor. After the
extraction phase is completed, then it will go to the liquor evaporation.
Figure 3. Extraction process of roast and ground coffee
d. Evaporation
Evaporation process aims to evaporate the solvent of coffee extract to obtain a more viscous and reduced water content. Tool that was used to evaporate liquor is
evaporator. In the evaporator, the liquor will be evaporated inside the tube. The heating
medium used is a steam. The heat from the steam will be transferred trough the tube into the coffee extract. Steam temperature will decrease and then be condensed.
Steam condensate will be separated and collected then sent back to the boiler. In the boiler, condensate will be processed back into steam.
Figure 4. Evaporation process of coffee extract This process affects the next step because if the evaporation rate is low then
the spray drying should be done longer and it increase production cost.
24
e. Spray Drying
