Each coffee cherry usually contains two coffee beans with their flat sides nestling against each other.

The coffee beans inside the cherry are green in colour, their natural state as a seed.

Some coffee cherries, around 5%, contain only one coffee bean, this bean is referred to as a Peaberry.

As this Peaberry doesn’t have another coffee bean to push against it is round in shape instead of having one flat side.

The coffee beans contain between 0.8% and 2.5% caffeine, a natural stimulant which makes coffee a very popular drink and the green coffee beans the world’s second valuable traded commodity, behind only petroleum.

Coffee Bean (Roasted)

The brown coffee bean we are all used to seening in our local coffee shop is actually the final product from the coffee roasting process.

The green beans are roasted in a large heated drum for between 8-15 minutes until brown in colour and are ready to send to coffee shops, supermarkets and our homes.

There are four main ways of grinding coffee beans, pounding, rolling, chopping and burr grinding.

Pounding is used for Turkish coffee where the grounds need to be very fine, almost powdery as the coffee is put in a pot without a filter.
This is usually done with a pestle and mortar though a mill is starting to be come the norm these days.

Rolling coffee beans is done by grinding the coffee beans through 2 corrugated rollers.
This method produces a even, consistent grind and there is little heat to damage the coffee.
Due to the size of the machinery and the costs included, this method is used exclusively by commercial coffee roasters and retailers.

Chopping is done by fast moving blades in a enclosed container. These are usually specifically designed for the task but this can be done in a standard blender.
Chopping gives varied results, often ending with a mix of coarsely and finely ground coffee which in not desired for good coffee extraction.
Coffee choppers are cheaper to produce and as such are usually only produced for the domestic market where the cost of a burr grinder can be prohibitive.

Domestic coffee chopper and top view of the blades

Burr grinders use disks or conical grinding elements which the coffee beans are ground between.
This constant distance, similar to rollers, allows for an even, more consistent grind.
A consistent grind produces a better cup of coffee when filtered or used in an espresso machine.
Burr grinders also produce very little heat so don’t effect the taste of the coffee.
They are the standard for commercial coffee grinders and used in the majority of coffee shops and quality coffee retailers.
Burrs are also used on high end domestic coffee grinders, though these tend to be the slightly cheaper disk types.

Commercial coffee grinder with hopper

Commercial coffee grinders usually have a hopper on the front allowing coffee to be ground in batches then quickly dispensed when needed.
This is very useful for very busy coffee shops as it saves on time, however when the ground coffee is left it quickly goes off, with a noticeable difference with in 20 minutes.

Becoming more popular are on demand grinders, as the name suggests these allow the coffee beans to be ground on demand, ie when the coffee is needed.
On demand coffee grinders are suitable to all but the very busiest coffee shops as the grinding only takes 5-10 seconds but makes sure the ground coffee is fresh every time.

Commercial on demand coffee grinder

When done correctly the espresso will have a dark thick crema, carrying all the subtle flavours of the espresso into the cup.
Tamped incorrectly however leaves a bitter overpowering taste which is unfortunately usually covered up with sugar, syrup and milk.

The first point to note is to make sure the coffee beans are fresh roast and freshly ground.

Grinding should be done only when the coffee is ready to be made.
The oils in the bean are released once the shell is broken and the grounds will quickly go stale.

An on demand grinder is perfect here as coffee can be ground as and when it is needed at the touch of a button, providing fresh coffee grounds with no waste.

The coffee is ground into the group head in a 7 gram measurement for a single shot of espresso and 14 grams for a double.

Before tamping the coffee should be leveled, this is usually done by running a curved finger over the head to level the coffee with the top of the rim.

A Coffee Tamper

The first tamp should be quite light, around 5 pounds of pressure, to form a puck shape from the coffee grounds.

A good way of gauging the amount of pressure needed is to practice on a bathroom scale.

The final tamp should be around 30 pounds of pressure to leave a compact coffee puck to give the desire resistance to the water.

While still applying the pressure the tamp should be twisted through 720° to leave a smooth surface on the coffee, essential for even distribution of the water through the coffee.
The coffee should also be level as if at an angle the water will push through the low side giving a bitter taste to the coffee.

If done correctly the extraction should take 20-25 seconds and leave a nice crema and produce all the subtle espresso flavours.

There are more than 90 species of coffee plant but only a portion of these are used to make the coffee drink.

Coffee Plants

Coffee plants used to make the coffee drink are usually grown in tropical and sub-tropical countries on large farms or plantations.

These tropical plants are small trees that grow to a height of 3-4.5 meters (10-15 feet) and live for 50-70 years on average.
Coffee plants leaves are broad, waxy green and thickly cover the branches.
They bear fruit, coffee cherries,  after 3-5 years and then for the rest of their lifespan.
They also produce sweet, jasmine like flowers in huge quantities.

Coffee Cherries on a Coffee Plant

There are 2 main types of coffee plant grown and harvested around the world, Coffea Arabica and Coffea Robusta.

Robusta is grown at lower elevations than Arabica and  produces a greater yield of coffee beans per plant.
It is also a more robust plant, more resistant to disease and bad weather.

Robusta coffee contains twice as much caffeine, which gives coffee its bitter taste, as Arabica.
As such Robusta is classed as a lower quality coffee than Arabica, often being used for instant coffee, especially due to its lower production costs.

Arabica is grown at higher elevations often on the side of hills and mountains and makes for all the worlds best coffees.
The lower caffeine content gives a smoother taste preferred the world over.
Arabica needs plenty of sun and water with low pH soil and is often grown in volcanic regions as the soil there is perfect for Arabica growth.

Arabica contributes around 75% of all the worlds 8 million or so tons of harvested coffee each year.

Arabica coffee plant

]]> http://www.coffee-machine.org/the-coffee-plant/feed/ 2 http://www.coffee-machine.org/coffee-roasting/ http://www.coffee-machine.org/coffee-roasting/#comments Wed, 25 Mar 2009 11:54:53 +0000 Coffee Machine http://www.coffee-machine.org/?p=135 Roasting is performed in a large special made roasting machine, which look like an extra large tumble dryer.
The green coffee beans are poured into the roasters cylindrical container which is preheated to an exact temperature.

The beans are then spun around in the cylinder to ensure they are heated evenly.

Through out the process the person roasting keeps a very close eye on the beans by checking their temperature, time, smell, appearance and the sound they make.
The sound and appearance is checked by taking a small sample from the drum by means of a tryer.

Commercial Coffee Roaster

The whole process usually takes between 10-15 minutes dependant on the type of taste require.

• A quicker roast, around 8 minutes,  gives a light more acid taste and is referred to as a cinnamon roast
• A medium roast, 9 to 11 minutes, gives a light brown slightly sweeter taste with more balanced acidity and is known as full city.
• A longer roast, 12-14 minutes, give a much darker beam with a sweet chocolaty taste though still holding some of the acidity. This is referred to as a Vienna roast and is highly popular.
• Finally a very long roast, 15+ minutes, give a very dark, almost black bean. The sugars have carbonised giving a smoky intense flavour, though its has now lost the subtle coffee flavour. The is know as a French roast.

Once ready the roaster door is open and the coffee beans tumble onto a cooling tray below.
The beans are spread evenly over a screen which has small holes allowing air to be drawn over then beans helping to cool them.

When the coffee beans have cooled they are ready to be packaged for sale or made into a cup of coffee.

To grow coffee you need three main things.

• Moderate rainfall, too much or too little will ruin the crop.
• A frost free climate.
• Lots of sunshine.

Though the conditions can vary, producing different types of coffee, these main requirement need to be met.

Coffee is produced in various regions across the world, these can be grouped as the Americas, Africa and Arabia, and Indonesia.

Inside of these three regions the coffee plant grows in around 80 different countries with Brazil begin the largest grower.

Coffee Producing Countries

In these countries, coffee can grow at anywhere from sea level to 6,000 feet (1,828 meters) in lots of different types of soil and local climates.

The higher quality coffees need more exacting conditions however.
These coffees need to be at high altitudes, between 4,000 to 6,000 feet (1,219 to 1,828 meters) and only grow in select mountainous regions between the Tropic of Capricorn and the Tropic of Cancer.
They also need around 80 inches (203cm) of rainfall annually, and the rainy and dry seasons must come in set periods.
Cloud and mist needs to present on regular intervals to block overexposure to the sun.
The soil must be very fertile and is often volcanic as this is rich in nutrients and generally considered the best type of soil for crowing crops.
Finally the average temperature must be held around 60-70°F(15-21°C) which by tropical standards is quite cool.
This lower temperature means the growing period is longer, which leads to denser crops and a more intense flavour.

Coffee grown outside of this area and at lower altitude still produces good coffee but tends to have  a more simple taste without the intense flavour of the higher grown beans.

Coffee Harvesting

The coffee tree’s cherries are harvested individually by hand.
This process allows the coffee to be collected when its is ripe and means it is handled with care.
The average coffee tree will be returned to several times over a harvest as all the cherries do not ripen at the same time.

Once collected from the trees the next process is to remove the seed ‘the coffee bean’ from inside of the cherry.

Removing the bean from the cherry involves removing four outer layers.

These are the tough outer layer, the sticky pulp layer, a stiff parchment casing and finally the thin silverskin that wraps around the bean.

Cross-section of a Coffee Cherry

There are two methods of removing the coffee bean, the wet and dry methods.

Which one is used depends mainly on the availability of fresh clean water and has a significant impact on the flavour of the coffee.

The wet method involves removing the bean from the pulp in purpose built machinery.
After removing the bean from the pulp, it is then placed in a fermentation tank where water is added to start the fermentation process.
This process usually last between 12 and 36 hours, but must not be allowed to go over this time as the ripen fruit can soon become rotten.
Once fermentation is complete the beans are washed free from the remaining pulp then left to dry.
The drying is done on large patios and the beans are raked several times a day to ensure the beans dry evenly.

The dry method is a lot more simple but doesn’t give the clean even taste associated with the wet method.
The dry method simply involves leaving the coffee cherries out in the sun for several weeks until they are dry.
The beans are then simply separated from the dried cherry.

Whichever method is used the next stage is to remove the parchment and the silverskin from the bean by milling.
Once done they are sorted by size to make sure of even roasting and any foreign materials, twigs, stones and so on are removed.
These beans are ready to be shipped to roasters and retailers in their now ready ‘green coffee’ state.

The coffee beans were crushed into balls with animal fat and eaten as quick high energy snacks for long marches and during warfare.
The fat, protein and caffeine in the balls provided energy and alertness, making an early form of energy bar!

Coffee first begin to be made into a drink around 1000 A.D.

Coffee History tells the story told is that a young Ethiopian goat herder, Kaldi,  noticed his goats behaving frenetically after eating some red berries from a near by bush.

Kaldi tried some of the berries for himself and found to his amazement that he felt awakened and began to dance around with his goats.

Kaldi soon developed this into a daily habit which was noticed by a monk from a near by monastery.

The monk tried the berries for himself, noticed the effect and had the idea of boiling the berries into a drink.

The monks used this drink to help stay away during long religious services and the first version of coffee was born.
This drink spread from monastery to monastery and then through out the Middle East.

Kaldi and Goat

By about 1100 A.D. coffee trees were starting to be cultivated on the Arabian peninsula.
The Arabs were the first people to roast the coffee bean and boil it in to a drink.

The first written accounts of coffee in history were by a philosopher and astronomer Rhazes (850-922 A.D.) followed by the philosopher and physician Avicenna of Bukhara (980-1037 A.D.).

Avicenna wrote about a drink called ‘bunchum’ which many believe to be coffee, “It fortifies the members, it cleans the skin, and dries up the humidities that are under it, and gives an excellent smell to all the body”

The popularity of coffee continued to spread and the worlds first coffee house opened in Constantinople in 1475.

By the late sixteenth century, European travellers to the Middle East had noted the drink in their travel journals, describing that it was often used as a medicine for a huge range of illnesses, the most relating to the stomach.

A German physician Leonhard Rauwolf described in his travel journal one of the earliest European accounts of coffee, writing “they have a very good drink they call Chaube (Coffee) that is almost as black as ink and very good in illness, chiefly that of the stomach. Of this they drink in the morning early in open places before everybody, without fear or regard, out of China cups, as hot as they can…”

The first coffee introduced into Europe was done so by Venetian traders in the early seventeenth century.
Coffee was imported through the busy ports of Venice and Marseilles and the European coffee trade network began.
Once coffee was in Europe, word of it spread with travellers, the more enterprising ones importing the bean with them.
The first European coffee house opened in Italy in 1645.

England’s coffee history began when the first English coffee house was opened in 1650 in the university town of Oxford.

Its popularity grew quickly, especially amongst the local students who made the local coffee houses their regular meeting places giving birth to England’s first social clubs.

Two years after the coffee houses arrived in Oxford, a man named Pasqua Rosée opened London’s first coffee houses.
The coffee house was so popular that by 1715 there was as many as 2000 coffee houses in London alone.

Edward Lloyd opened his coffee house in 1688 catering mainly to sailors and merchants.
While running this coffee house, Edwards established a list detailing ships cargo and schedules.
London’s underwriters came to his coffee house to sell shipping insurance and merchants came to keep track of ships.
From this bustling coffee house arose Lloyd’s of London, today one of the worlds largest insurance companies in the world.

Lloyds of London Coffee House

Coffee made its way into France in 1657, made popular in Paris by a Turkish ambassador, Suleyman Aga.

Austria coffee history began when they stumbled upon coffee in 1683 after the Battle of Vienna.
The defeated Turks left behind their supplies including thousands of livestock and camels as well as several thousand sacks of exotic foods, including several hundred sacks of coffee.

At first the coffee was thought to be animal feed, but a Pole in the army named Kolshitshy knew of coffee from his travels through the Middle East and opened Vienna’s first coffee house.

The Dutch were the first to cultivate and transports coffee commercially, through their colonies. in early to mid 1600.
They intentionally acquiring colonial land with the intent of cultivating coffee.

They were so successful that for many years the Dutch controlled the worlds coffee price.

Though coffee was therefore highly important though the colonies it wasn’t until 1668 that coffee was introduced to America, 44 years after New York was settled.
By the end of the century however, there were coffee houses in all the major cities.

High tax levels on Tea and the end of the United States colonialism, dramatically reflected by the Boston Tea Party, made tea very unpopular in America and coffee which could be imported directly from the Caribbean the drink of choice.

Coffee made its way to Brazil in the form of a seedling smuggled out of France in 1727.
Brazil and with it Columbia grew to be huge coffee producing power houses, with Brazil being the worlds largest producer today (2009).

Colombia is now the worlds third largest producer, due to Vietnam taking second place in recent years.

Vietnam has become a major producer of the cheaper but very popular robusta beans. These beans are favoured by larger companies an are popular for use in instant coffee.

The first coffee machine was made in 1818.