Taste is a matter of personal preference, this is certainly true when it comes to
coffee. The consumers of each country require different characteristics in their daily cup
of coffee. They may like, for example, a strong, or equally, a somewhat milder flavour.
Such differences in taste may even occur within the same country at a regional level.
Coffee specialists carry out a lot of research into taste per country. It is important
to obtain information regarding the habits and preferences of the consumers, in order to
adapt the coffee to their tastes.
Blending for a stable taste
To produce the desired flavour, various coffee varieties are blended together.
The principal aim in blending coffee is to arrive at a flavour and aroma which can be
continually reproduced. The blender uses recipes which have already proven that they meet
the taste criteria of a certain region. Coffee is a natural product, and given that the
quality of the harvest is unstable, the recipes for blends must be regularly adjusted.
First blend, then roast
As a rule, different coffees are combined while still raw, to produce what is
referred to in the trade as 'blends'. A very small number of roasters prefer to blend
their coffees after roasting. Four or more different varieties are necessary in order to
achieve the particular flavour required because only by blending can the natural
fluctuations in quality amongst the different varieties be compensated for.
Coffee's characteristic flavour and aroma develop during the roasting process. The
flavour is locked within the green coffee bean until it is roasted. Heating green coffee
beans sets a series of complex chemical reactions in motion that release the flavour
compounds hidden within each bean.
Art and science
Roasting coffee beans to perfection is an art as much as a science, since they
may react differently to the roasting process, depending on the soil and weather
conditions in which they were grown and the processing method used. Different types of
coffee require different roasts to bring out their rich flavours. An experienced roaster
adjusts the roasting time and temperature for each batch of beans so they can reach the
peak flavour and desired roast.
The roasting process
During roasting the green beans are exposed to very high temperatures of 500
degrees Celsius. The temperature in the bean rises to between 200 degrees Celsius to
250 degrees Celsius, bringing about changes in chemical composition. The moisture in the
beans evaporates, releasing the aromatic oils; the beans are reduced in weight while
at the same time they increase in volume. The sugars in the beans are converted into
caramelised sugars, giving the coffee beans a distinct
flavour and a deep brown colour.
The temperature and length of roasting determine the characteristics of the end
product. Once the desired roasting temperature has been reached, roasting is terminated.
The roasted coffee is moistened and cold air is blown through the roasted coffee beans.
There are three types of roasting:
- Light or blonde roasting gives coffee a mild flavour, which is drunk for example in
- Medium roasting produces a somewhat stronger flavour, as is popular in Central Europe
and the USA, among others.
- Dark roasting results in very strong bitter flavoured coffee intended to be drunk black,
for southern European tastes.
The coffee beans are usually ground after roasting, in so-called rolling mills. A
coffee bean can not be ground fine enough in one time to be suitable for the modern filter
systems. A rolling-mill consists of several groups of cylinders, placed on top of each
other. The beans are fed between two finely ribbed cylinders, which turn in opposing
directions. The first group grinds the coffee beans coarsely, which is called
pre-crushing. Each next group grinds the coffee finer until the desired grind size is
reached. The spacing of the cylinders is adjusted according to the required fineness of
the ground coffee.
Transport, preservation and advertising, the three most important functions of
packaging, were originally unnecessary for roasted coffee, since, until the middle of the
19th century, and in many places even later, there was no industrial roasting. The
proprietor of the coffee house purchased his supply of raw coffee and roasted the beans
himself. For domestic purposes as well, raw coffee beans were purchased form the grocer
and roasted at home.
Nowadays, to guarantee as far as possible that the flavour of the coffee enjoyed by the
consumer is as good as when it left the factory, ground coffee is very often vacuum or
soft-vacuum packed, so that no air can get in. The quality of ground coffee is quickly
diminished by oxygen in the air; oxygen breaks down the precious aromas in the coffee, and
the flavour becomes more and more flat. That is why the best roasters pack the delicate,
fresh roasted ground coffee in vacuum packages.
Unopened packets always have a quality guarantee for a specific length of time. This
best before date is printed on every packet.
source: Douwe Egberts