Coffee is prepared from the roasted seeds of the Coffea plant and is slightly acid. A brief overview on the course of coffee production:
Processing: berries have been traditionally selectively picked by hand involving the selection of only the berries at the peak of ripeness yet more commonly crops are strip picked by person or machine, where all berries are harvested simultaneously regardless of ripeness . After picking, green coffee is processed either by the dry process method, which berries are strip picked, or the wet process method, which incorporates fermentation into the process and yields a mild coffee.
Roasting: the seed decreases in weight as moisture is lost and increases in volume, causing it to become less dense. The roasting process influences the taste of the beverage by changing the coffee seed both physically and chemically. The actual roasting begins when the temperature inside the seed reaches approximately 200 °C though different varieties of seeds differ in moisture and density and therefore roast at different rates.
Storage: air, moisture, heat, and light are the environmental factors responsible for deteriorating flavor in coffee seeds. The most common method is to store coffee in vacuum packed cans, in which 99% of the air was removed and the coffee in the can could be stored indefinitely until the can was opened.
Brewing: there are many brewing variations such as the fineness of grind. The ideal holding temperature is 79 to 85 °C and the ideal serving temperature is 68 to 79 °C.
Reference: Thecoffeefaq.com, Wikipedia