Beverages occupy an important part of the routine diet all over the world, especially in India. Coffee is considered as one of the most popular beverages in the world. Half of the total coffee production of the world comes from Brazil. The major coffee producing states in India are Karnataka, Kerala and Tamil Nadu. Coffee is obtained from fruit of an evergreen shrub and the main species being coffee arabica and coffee robusta.
Steps involved in coffee processing:
Coffee berry develops from the flowers of coffee plant. The first step in the preparation of coffee beans is the removal of the pulp in two ways, namely mechanical method and soaking method. Soon after the removal of pulp fermentation is carried out so as to ring out the natural aroma of coffee beans. During this stage, lots of chemical changes occur in the beans due to the reduction of carbohydrates. The fermented beans are then washed and dried thoroughly.
The next step in coffee processing is the roasting process. It serves as a very important step in coffee processing because it acts as the processing method which brings out the fullest flavor of coffee. The basic procedure of roasting involves the removal of moisture and the color is changed to dark brown. The tannin content namely the chlorogenic acid content is reduced and the fat content is converted to caffeol, a group of essential oils. The carbon-dioxide content formed during roasting remains intact in coffee even after roasting
The final most steps in coffee processing are grinding. Once the roasted coffee is ground, the aroma gets lost very quickly. Hence it is very important to pack the ground coffee under vacuum conditions.
What happens to coffee when boiled?
Processed coffee is composed of tannin, caffeine, caffeol, caramelized sugar and carbon carbon-dioxide. When the coffee is boiled in water, the volatile oils are lost thus leaving behind the bitter-tasting tannins. Hence heating the coffee repeatedly makes it bitter and hence should be avoided. It is caffeol that brings about the flavor to the coffee. Coffee also contains a component called trigonelline which is converted to nicotinic acid on roasting.
While preparing coffee, it is better to extract the maximum amount of caffeine and caffeol but little amount of tannin. The following methods are commonly used to prepare coffee. Let’s see the different types of coffee preparation methods:
v Drip method
v Vacuum method
v Percolation method
v Steeping method
Green coffee does not require the roasting process and are found to be more stable than the processed one. This is because of the reason that grinding and roasting loses carbon dioxide and the unsaturated volatile compounds are chemically altered.