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When hot water comes into contact with ground coffee, the aroma, flavour and colour
constituents are released. Just how many of these components finally end up in the cup is
determined by the grind size, water quality and quantity and brewing temperature, as well
as the length of time the water is in contact with the ground coffee (brewing time). Very
simply, fine ground coffee, a high temperature and a longer brewing time result in more of
the components being dissolved and released. If too much of the content is removed in this
way, the coffee tastes strong and negative bitter. Grind size, contact time and
temperature should on one hand allow extraction of many of the water soluble components,
but on the other hand prevent extraction of negative bitter components.
Centuries of coffee brewing
It is therefore hardly surprising that the search for optimal quality in coffee
as a beverage gave rise, especially in the 18th and 19th centuries, to the development of
a whole host of infusion methods, most of which have since disappeared. Many of these
methods served to prepare the ground for today's brewing methods. The idea of boiling the
ground roasted coffee in water comes from Arabia.
The principles of brewing great coffee are always the same, no matter which
type of equipment you use:
- Always make sure your coffee maker is clean
- Use fresh water to brew the coffee
- Rinse the coffee pot well before you start
- Use fresh coffee. After opening the packet, keep the coffee in a tightly-sealed
container
- Buy the correct grind for your machine
- Use the same amount of coffee each time, in order to gain as
consistent a flavour as possible
- Make sure the coffee is evenly distributed within the filter bag
- The best drip filter and French press coffee is brewed at around 96 degrees Celsius.
Moka express and Espresso coffee is ideally brewed at 90 degrees Celsius. The ideal
temperature to serve it at is around 80 to 85 degrees Celsius.
- Coffee is at its most delicious directly after being brewed.
- For a uniform flavour, the coffee in the pot should be stirred before pouring.
- Do not leave coffee standing on the hot plate for too long, or the fine aromas will be
lost. If you wish to keep the coffee longer, use a thermos flask.
- Remember to de-scale the coffee machine every so often. How often you need to do this
depends on the hardness of the water in your area.
- Use clean crockery
The drip filter, either manual or automatic, is nowadays, together with the espresso
and the Mediterreanean method, the most popular method of brewing coffee worldwide.
The drip filter system consists of two compartments, an upper and a lower one, divided
by a filter.
Manual drip
In the manual drip filter the ground coffee is placed in the cylindrical or
conical upper part and water (just off-boiling) is poured over it in steps. The brewed
coffee drips through the metal, ceramic or plastic filter. The grind size of the coffee
should be as fine as the holes in the filter allow. This means that the holes should not
clog and no grounds should be in the coffee brew. Generally coarsely ground coffee is used
in the cylindrical filter. In the conical filter, filter paper and finer ground coffee can
be applied.
Electrical drip
The procedure can also be done by the numerous electrical drip filter machines
that are available. The upper part is usually cone-shaped and contains a filter paper or a
gold filter with very small holes. The water is near-boiling and sprayed over the coffee
grounds. Because the holes in the filter system are smaller, the coffee can be ground
finer. In the electrical machines there is generally also a device to keep the coffee
warm, but keeping the brew on the heating plate too long is often detrimental to quality.
Other factors which affect the quality are the contact time and the water/coffee ratio.
Espresso is originally an Italian method. It is drunk worldwide nowadays, both at home
and out-of-home.
The term 'espresso' is often used for a type of coffee, but it is actually the term for
the brewing procedure. Espresso means coffee that is made at the moment when it is
requested and it refers to a quick infusion of water through coffee grounds using either a
stovetop or an electrical machine. The difference with other brewing systems is that the
water is forced under pressure through finely ground coffee packed tightly over the
filter. With an espresso machine a cup of coffee can be ready in around 25 seconds.
Moka express or Neopolitan
In the stovetop version, also called Moka express and sometimes Neopolitan, water
in the bottom chamber is heated, the resulting pressure (max. 1.5 bar) forces the water up
through a filter containing packed ground coffee, at the end the coffee brew arrives in
the upper chamber.
Electrical espresso
The electrical models inject hot water through the ground coffee directly into a
cup. In this machine, pressure is built up by a pump in combination with the coffee bed
and the sieve and should be at least nine bar. To build up this pressure the grind should
be perfect, which not only means very fine but also with a certain particle size
distribution. For espresso usually a dark roast is used, which is, however, not essential.
Usually the espresso coffee has a high dry solids content, but really discriminating is
the richer flavour and aroma, more body and a pleasant aftertaste and last but not least a
beautiful, stable, creamy layer on top.
Two brewing methods are related to the drip filter system:
Neopolitan flip
A special version of the manual drip filter is the Neopolitan flip. In this
system the coffee is secured between the compartments instead of being laid loosely on top
of the filter. The water is heated in the bottom part of the pot. When the water is nearly
boiling, the pot is flipped over and the water drips through the coffee bed into the
empty side.
Percolator
The percolator was originally a drip filter system. Later the pumping percolator
was invented. Nowadays this method is out of fashion, although still used in American
households.
In this system water is heated and pumped (top to bottom) through the coffee. Then the
brew is circulated again and again until the coffee has the desired strength. This method
is quite controversial, because during brewing a lot of the aroma is lost. By controlling
the temperature of the water perking through the coffee bed, deterioration can be limited.
French press or plunger is a method which is very trendy nowadays. It is used all over
western Europe. A coarsely ground coffee is placed in a cylindrical coffee pot and water
just off boiling is added. Then the plunger is inserted on top of the cylinder. After a
few minutes soaking (circa four min) the plunger is pushed down through the coffee brew
taking the ground coffee to the bottom of the pot. The clarified coffee is served directly
from the cylinder. The coffee should be coarsely ground, because otherwise the plunger is
very heavy to handle and there is a chance of fines in the brew. The used coffee blend and
the brewing time determine the quality of the brew.
Plunger
A method which is related to the plunger is the open-pot or boiled coffee. This
gets more and more out of date, but is still in use by people in the countryside, elderly
people and also in Scandinavian countries. In the USA this method is also known as Hobo
coffee and can still be seen in Westerns. The preparation is comparable to the plunger,
but sometimes the coffee is left boiling for a while. After brewing there are methods to
help the sedimentation of the coffee grounds, like adding a drop of cold water. Another
possibility is to filter the coffee, most often over a filter cloth.
This method is used throughout the Middle East, North Africa, Greece, part of Eastern
Europe and Russia. It seems to be the most basic method to prepare coffee, almost a
ritual.
Ground coffee and water are placed in a metal coffee container, called Ibrik
(Turkish), Briki (Greek), Findjan (Arabic) or Turku (Russian), often together with the
same amount of sugar and sometimes even spices (like cardamom). The water is heated until
boiling and a foam layer appears on the coffee. Then it is taken off the heating plate or
fire. This process is sometimes repeated up to three times. The coffee including the
coffee particles (fines) is served in small cups.
Roast per region
This Middle Eastern coffee is unique since it is drunk with coffee grounds. For
this reason the coffee is brewed from very finely ground coffee, almost a powder. The
degree of roast for this coffee varies with the region. Part of the Middle East uses very
dark roasted coffee, while in Greece and part of Turkey very light roasted coffee is
preferred.
One of the most important quality factors is the thin brown creamy layer on top, called
kaimaki by the Greek. It is even a sign of your qualities as a host.
Brew in the cup
Related to the Middle Eastern method is the method by which the coffee is brewed
directly in the cup. This is drunk in parts of Eastern Europe, like the Czech Republic.
Finely ground coffee is put directly in a cup and boiling water is added. This coffee is
also drunk with coffee grounds.
This aesthetic system consists of a globe (usually made of glass) containing the water
and a bowl on top of it containing the ground coffee. Between them there is a filter of
metal or cloth or simply a glass stopper. The water is heated and rises through the filter
into the bowl with coffee. After all the water is transferred into the bowl containing the
coffee, the mixture is allowed to steep and the heat is turned off. When the system cools
a vacuum will develop in the globe in which the water was before and the brewed coffee is
drawn into it through the filter.
For daily use this system is probably not appropriate, but it is a very decorative
method that results in a very good brew. It is most suitable for special coffee types.
Retro system
A system that resembles the Cona is the Retro system. In this system the bowl is
not on top of the globe but beside it. The procedure is similar. Interesting with the
Retro system is that the flame is turned of automatically when the water from the vessel
is transferred into the coffee bowl.
The addition of milk and sugar
The definition of the perfect cup of coffee does not exist, because taste differs
from person to person. While one person will drink coffee black in order to enjoy the
exquisite aroma at its best, another will add milk and/or sugar for the desired taste.
The amount of milk and/or sugar a person adds to the coffee will affect the way it tastes.
The flavour of either of these also plays an important role; among all the different types
of milk and cream alone there are enormous variations. At home we tend to use the same
product all the time, but when we go out there may be any number to choose from.
Flavoured coffees
Flavoured coffees are increasing in popularity with consumers, attracting many
novice coffee drinkers who grew up on soft drinks, and other people who were not coffee
drinkers in the past.
Allthough flavoured coffees began appearing in the United States in the 1970s, the
tradition of flavouring coffee actually dates back to coffee's beginnings in the Middle
East, and the tradition continued when coffee came to Europe. Early coffee drinkers in
Yemen and Arabia added spices such as nutmeg and cinnamon to their brew, and 17th century
Europeans added chocolate and citrus to their coffee. Adding liqueur is a long-standing
tradition as well.
Grinding exposes the beans' cell walls and prepares the beans to release their flavour
during brewing. Because of variations in the length of the brewing cycle, the water
temperature and the water agitation pattern, each brewing method requires different
degrees of grind.
Effects of Grind
Since there are so many different ways to brew coffee, choosing the correct grind
is essential to get the optimal flavour extraction during brewing. The degree of
extraction depends on three things:
- the fineness of the grind
- the ratio coffee / water
- the length of time the grounds have been in contact with the water
Generally, the shorter the brewing cycle, the finer the grind required to produce
optimal flavour extraction. The longer the brewing cycle, the coarser the grind required.
Fine grinds expose more of the coffee's surface area to the water and the coffee's
essential oils are released faster. Longer brewing methods require a coarse grind to avoid
over-extraction. For example, espresso brewers can produce a cup of espresso in just
20 seconds, so they need a very fine grind. A grind that is mismatched to the brewing
method can produce a bitter, overly strong coffee, or one that is weak and lacking in
flavour.
source: Douwe Egberts |
