Coffee Making Process

Coffee production refers to the conversion of green coffee beans into a soft drink. It includes the process of roasting the green beans, grinding the roasted beans and then mixing the grounded coffee with water.


Process of Making Coffee:

1. Roasting:
Roasting coffee transforms the chemical and physical properties of green coffee beans into roasted coffee products. When roasted, the green coffee bean expands to nearly double its original size, changing in color and density. Coffee can be roasted with ordinary kitchen equipment (frying pan, grill, oven, popcorn popper) or by specialized appliances.

2. Grinding:
Beans which are too finely ground for the brewing method in which they are used will expose too much surface area to the heated water and produce a bitter, harsh, "over-extracted" taste. At the other extreme, an overly coarse grind will produce weak coffee unless more is used.


Types of grinding:

a)     Burr Grinding (Link)
       (Conical burr grinders)

b)     Chopping (Link)
       (Two blades)

c)     Pounding (Link)
       (Mortar and Pestle: e.g. Domestic sugar grinding)

d)     Roller Grinding ( )


Principles of Grinding:

There are certain principles which must be acknowledged and understood because they are the cornerstone of successful grinding.

1. The greater the friction in grinding, the hotter the coffee bean gets while grinding. This changes the flavor.

2. The more uniform the particle size, the more control the brewer has.

3. The finer the grind, the more coffee area per bean, the greater the brewing area, the more flavor extracted from the bean.

4. The finer the grind, the greater the water resistance, the more pressure required to push water through the grind.





Ways of brewing the coffee:

1.  Decoction (Boiling)

The simplest method is to put the ground coffee in a cup, pour hot water over it and let cool while the grounds sink to the bottom.

2.   Infusion (Steeping)

The grounds are placed in the cylinder, and boiling water is then poured into it. The coffee and hot water are left in the cylinder for a few minutes (typically 4–7 minutes) and the plunger is pushed down, leaving the filter immediately above the grounds, allowing the coffee to be poured out while the filter retains the grounds.

3.   Gravitational Percolation (Drip Brewing)

The grounds are placed in the cylinder, and boiling water is then poured into it. The coffee and hot water are left in the cylinder for a few minutes (typically 4–7 minutes) and the plunger is pushed down, leaving the filter immediately above the grounds, allowing the coffee to be poured out while the filter retains the grounds.

4.  Pressurized Percolation (Espresso)

Espresso is made by forcing hot water at 91–95 °C (195–204 °F) under a pressure of between eight and fifteen bars (800–1500 kPa, 116–220 psi), through a lightly packed matrix, called a "puck," of finely ground coffee.