Roasting

Inside this subsection are:

What is roasting?

Roasting is a process during which flavour compounds “hidden” within each green coffee bean is released through a set of chemical reactions. The flavour, acidity, aftertaste and body of coffee are heavily dependent on this process. The roasting process includes the following series of steps:

Beans-absorb-heat stage: green beans are dried to a yellow colour. During the early part of this stage, coffee beans often obtain a humid grassy smell, as water is being removed from the beans. Later, the beans begin to smell like toast or popcorn.
First crack stage: the beans double in size and experience a decrease in weight. This phase often cracks the seeds. Their colour changes to a light-brown, then medium-brown. Changes in the chemical composition of the beans occur during this stage.
Beans-release-heat stage (also called Second crack stage): the sugar in the beans begin to caramelise, creating “coffee oil”.

Method

How to roast?
The most common roasting methods are drum roasting and hot air roasting:

Drum roasting: a machine-used method which roasts the coffee beans as they tumble in a rotating drum which is heated by gas or wood. At the end of this process, coffee beans are cooled in a cooling hopper.
Hot air roasting: coffee beans are roasted by a hot-air roaster while tumbling through a current of hot air.

Roasting degree

There are many different roasting degrees, which lead to the different characteristics of coffee:

Roast degree	Characteristics
Light	Light brown to cinnamon colourLow body and light acidity. The beans are dry. This roast is too light and does not allow the coffee flavour to develop to its full potential.
Medium – Light	Medium light brown colour. The acidity brightens and the bean size increases slightly. The bean is still dry.
Medium	Medium brown colour. The acidity continues to increase and the beans become more potent. The bean is mostly dry.
Medium – Dark	Rich brown colour. Very small droplets of oil appear on the surface. The acidity is slowly diminished and bean is most potent. This is the ideal roast for a well blended espresso.
Dark	Deep brownish/black colour. The bean has spots of oil or is completely oily. Subtle nuances are diminished. Flavour decreases, while body dominates.
Very Dark	Black surface covered with oil. All subtle nuances are gone, aroma is minor, and body is thin. This roast is characteristic of American espresso.

Do it yourself

Home roasting, as many people say, is not as difficult as you may think. In fact, it could be an intriguing experiment to undertake, and the results are often amazing! You may even roast coffee beans that have a better quality than professionally roasted coffee (the beans are much fresher). So why not try it for yourself?

There are several ways of home-roasting:

Skillet method
Oven method
Stove pop method
Air pop method

For more on these methods, visit: http://www.sweetmarias.com/

Each method has its own advantages and also disadvantages. Why not try them all to find out which method suits you the best? You needn’t become a roasting expert, but you can enjoy yourself during the process. Have fun!

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Bibliography

Websites:

The British Coffee Association
http://www.britishcoffeeassociation.org/

Sweet Maria’s
http://www.sweetmarias.com/

Coffee Universe
http://www.coffeeuniverse.com/

Coffee Research
http://www.coffeeresearch.org/

Holland By Mail
http://www.hollandbymail.com/