Sunday 20 March 2011

Coffee Roasting : How it Works

Commercial coffee roasting machine Coffee roasting is a chemical process by which aromatics, acids, and other flavor components are either created, balanced, or altered in a way that should augment the flavor, acidity, aftertaste and body of the coffee as desired by the roaster.


Roasting Coffee Beans

The first stage is endothermic.  The green beans are slowly dried to become a yellow color and the beans begin to smell like toast or popcorn.

The second step, often called the first crack, occurs at approximately 205 °C (400 °F) in which the bean doubles in size, becomes a light brown color, and experiences a weight loss of approximately 5%.  The corresponding Agtron number for this color is between 95-90 (Davids, 68-69).

In the next step the temperature rises from 205 °C to approximately 220 °C, the color changes from light brown to medium brown (Agtron # 60-50), and a weight loss of approximately 13% occurs (Davids, 68-69).  The resulting chemical process is called pyrolysis and is characterized by a change in the chemical composition of the bean as well as a release of CO2.

The second step is followed by a short endothermic period which is followed by another exothermic step called the second crack. This second pyrolysis occurs between 225-230°C, and the roast color is defined as medium-dark brown (Agtron #50-45) (Davids, 68-69). The second pop is much quicker sounding and the beans take on an oily sheen. 

Coffee roaster Espresso potential is maximized in roasting when you maximize the sweetness and aroma of the coffee while minimizing the bitterness and acidity.  Most people focus on the latter and therefore roast extremely dark, yet without sweetness and aroma the espresso will never be palatable.  This explains the unpopularity of straight espresso and the popularity of espresso based drinks where either milk or other flavors are used to replace the sweetness that was lost by roasting darkly. 




From 170-200°C the sugars in coffee begin to caramelize. From tasting pure sugar versus its caramelized component it is evident that uncaramelized sugar is much sweeter.  The dark color of coffee is directly related to the caramelization of the sucrose in coffee. Therefore, to maximize sweetness you want to minimize the carmelization of sucrose, yet you do not want to roast too lightly or bitter tasting compounds will not thermally degrade. Stop the roast somewhere between the end of the first crack and less than half way through the second crack.  Do not roast well into or past the second crack.  We recommend a roasting chamber temperature somewhere between 205-215°C.  Realizing the danger of the following suggestion we might recommend a color similar to the one below. 

Saturday 19 March 2011

Coffee Species : Coffea Arabica

This is the most sought after coffee specie with high quality tasting characteristics, little acidity and caffeine. Coffea Arabica is originally grown in the mountains of Yemen in the Arabian Peninsula (hereof its name - arabica) as well as the southwestern highlands of Ethiopia and southeastern Sudan. However the trees are now almost all mixed with another planted ones.


Arabica green beans can also be found in Boma Plateau in southeastern Sudan and on Mt Marsabit in northern Kenya. But it is unclear whether these are native species or naturalized.

Coffea Arabica is a bush which grows 9 to 12 meters tall but the height can be regulated in order to give more crops. The plant has an open branching system; its leaves are of a lustrous dark green color, have elongated form (6–12 cm long and 4–8 cm broad), and are opposite to each other. The blossom is white; the fruit is drupaceous (also called a "berry"), when it ages, its color ranges from bright red to purple and usually has two seeds (the so-called “coffee bean”).


Arabica coffeeIt takes up to 7 years for coffee Arabica to start yielding. Arabica is typically cultivated at a height of 1,300 and 1,500 m but there are species planted at the sea level and at 2.800 m height. The plant is able to stand low temperatures but not frost. It needs a little shade to be grown if opposite to Robusta which does very well under direct sun rays.

During couple of years after planting, coffea Arabica gives yield of small and very fragrant blossom. When flowers open on a sunny day, they crop great number of small green beans or berries. This can bring to low quality coffee beans and bad harvest in the following years as the bush tends to foster berries maturing, thus injuring its health. In order to avoid this, the plants are usually pruned.

Coffee blossom survives only several days and begin to fade away resulting in green berries. After awhile, the fruit begins ripening turning from green into yellow, light red and then deep red. These green coffee beans are called cherries and are ready to be picked now. The berries often ripen unevenly, thus there’s a need of hand picking to select ready beans of coffee and leave green berries to mature.


Arabica coffee berriesA so-called coffee tree can give from 0.5 kg to 5kg of dried beans depending on some specific tree features and climate. Each berry typically contains two locules with 2 beans inside, though it can also contain 3 or 1 bean called peaberry.

Peaberry (also caracoli) is a coffee bean. Usually coffee cherry is a fruit with two sections and 2 or even 3 beans inside it. But there are cases when only one of the two beans gets embryonated and the other vanishes. This pea-formed bean is called peaberry. Around 5% of all coffee beans yielded are green peaberry coffee beans.


Kona coffee is in fact an Arabica coffee variety grown on the slopes of Hualalai and Mauna Loa in the North and South Kona Districts of the Big Island of Hawaii. Solely coffees grown in Kona regions can be added "Kona" prefix. The peculiar "Kona" climate along with its sunny mornings, thick clouds or rains in the afternoon, and a rich soil are the perfect conditions for Kona coffee beans growth.

How to Grow a Coffee Plant at Home


The coffee plant, under normal conditions, grows in the warm sun and climates of the tropics. But thanks to the advancement of modern growing technology and science, you are now able to grow your own coffee plants indoor.

The preferred method of starting a coffee plant is from seed. Your best bet in obtaining seeds is from the people who actually live in the countries who grow the plants. For these people, it is as easy as plucking a freshly grown coffee cherry from a healthy specimen.

But what are you to do if you do not live in an area that grows coffee? You can pick up coffee plants from a green coffee supplier. Just type those words into your favorite search engine, and it will hand you several unique results.


Once the seeds are delivered from the supplier, you will then need to soak them in water for 24 hours. After this soaking, the seeds will need to be sown in damp sand.

The time it takes to germinate the seeds can vary quite a bit, from two months to six or more months. After germination begins, the coffee plant should be planted in soil. A soil that is porous and includes a high amount of humus is best. The PH level should be kept in the low range, with high nitrogen content.

When grown indoors the new coffee plants will need plenty of light. If grown outdoors even the mildest of cool temperatures can destroy the plant.


If you are wanting the best tasting coffee for your morning expect to wait up to three years for the plants beans to mature to peak flavor and strength.

Tuesday 15 March 2011

History of Coffee


The global spread of coffee growing and drinking began in the Horn of Africa, where, according to legend, coffee trees originated in the Ethiopian province of Kaffa. It is recorded that the fruit of the plant, known as coffee cherries, was eaten by slaves taken from present day Sudan into Yemen and Arabia through the great port of its day, Mocha. Coffee was certainly being cultivated in Yemen by the 15th century and probably much earlier. In an attempt to prevent its cultivation elsewhere, the Arabs imposed a ban on the export of fertile coffee beans, a restriction that was eventually circumvented in 1616 by the Dutch, who brought live coffee plants back to the Netherlands to be grown in greenhouses.
Initially, the authorities in Yemen actively encouraged coffee drinking. The first coffeehouses or kaveh kanes opened in Mecca and quickly spread throughout the Arab world, thriving as places where chess was played, gossip was exchanged and singing, dancing and music were enjoyed. Nothing quite like this had existed before: a place where social and business life could be conducted in comfortable surroundings and where - for the price of a cup of coffee - anyone could venture. Perhaps predictably, the Arabian coffeehouse soon became a centre of political activity and was suppressed. Over the next few decades coffee and coffeehouses were banned numerous times but kept reappearing until eventually an acceptable way out was found when a tax was introduced on both.

 By the late 1600’s the Dutch were growing coffee at Malabar in India and in 1699 took some plants to Batavia in Java, in what is now Indonesia. Within a few years the Dutch colonies had become the main suppliers of coffee to Europe, where coffee had first been brought by Venetian traders in 1615. This was a period when the two other globally significant hot beverages also appeared in Europe. Hot chocolate was the first, brought by the Spanish from the Americas to Spain in 1528; and tea, which was first sold in Europe in 1610. At first coffee was mainly sold by lemonade vendors and was believed to have medicinal qualities. The first European coffeehouse opened in Venice in 1683, with the most famous, Caffe Florian in Piazza San Marco, opening in 1720. It is still open for business today. The largest insurance market in the world, Lloyd's of London, began life as a coffeehouse. It was started in 1688 by Edward Lloyd, who prepared lists of the ships that his customers had insured.

The first literary reference to coffee being drunk in North America is from 1668 and, soon after, coffee houses were established in New York, Philadelphia, Boston and other towns. The Boston Tea Party Of 1773 was planned in a coffee house, the Green Dragon. Both the New York Stock Exchange and the Bank of New York started in coffeehouses in what is today known as Wall Street.

In 1720 a French naval officer named Gabriel Mathieu de Clieu, while on leave in Paris from his post in Martinique, acquired a coffee tree with the intention of taking it with him on the return voyage. With the plant secured in a glass case on deck to keep it warm and prevent damage from salt water, the journey proved eventful. As recorded in de Clieu's own journal, the ship was threatened by Tunisian pirates. There was a violent storm, during which the plant had to be tied down. A jealous fellow officer tried to sabotage the plant, resulting in a branch being torn off. When the ship was becalmed and drinking water rationed, De Clieu ensured the plant’s survival by giving it most of his precious water. Finally, the ship arrived in Martinique and the coffee tree was re-planted at Preebear. It grew, and multiplied, and by 1726 the first harvest was ready. It is recorded that, by 1777, there were between 18 and 19 million coffee trees on Martinique, and the model for a new cash crop that could be grown in the New World was in place.

But it was the Dutch who first started the spread of the coffee plant in Central and South America, where today it reigns supreme as the main continental cash crop. Coffee first arrived in the Dutch colony of Surinam in 1718, to be followed by plantations in French Guyana and the first of many in Brazil in the state of Pará. In 1730 the British introduced coffee to Jamaica, where today the most famous and expensive coffee in the world is grown in the Blue Mountains.

The 17th and 18th centuries saw the establishment across Brazil of vast sugar plantations or fazendas, owned by the country’s elite. As sugar prices weakened in the 1820’s, capital and labour migrated to the southeast in response to the expansion of coffee growing in the Paraiba Valley, where it had been introduced in 1774. By the beginning of the 1830’s Brazil was the world’s largest producer with some 600,000 bags a year, followed by Cuba, Java and Haiti, each with annual production of 350 to 450,000 bags. World production amounted to some 2.5 million bags per year.

The rapid expansion of production in Brazil and Java, among others, caused a significant decline in world prices. These bottomed out in the late 1840’s, from which point a strong upward movement occurred, reaching its peak in the 1890’s. During this latter period, due mainly to a lack of inland transport and manpower, Brazilian expansion slowed considerably. Meanwhile, the upward movement of prices encouraged the growth of coffee cultivation in other producing regions in the Americas such as Guatemala, Mexico, El Salvador and Colombia.

In Colombia, where coffee had been introduced by the Jesuits as early as 1723, civil strife and the inaccessibility of the best coffee-growing regions had hampered the growth of a coffee industry. Following the “Thousand Days War” of 1899 to 1903, the new peace saw Colombians turn to coffee as their salvation. While larger plantations, or haciendas, dominated the upper Magdalena river regions of Cundinamarca and Tolima, determined peasants staked new claims in the mountainous regions to the west, in Antioquia and Caldas. New railways, relying on coffee for profit, allowed more coffee to be grown and transported. The opening of the Panama Canal in 1914 permitted exports from Colombia’s previously unreachable Pacific coast, with the port of Buenaventura assuming increasing importance.

In 1905 Colombia exported five hundred thousand bags of coffee; by 1915 exports had doubled. While Brazil desperately tried to control its overproduction, Colombian coffee became increasingly popular with American and European consumers. In 1914 Brazil supplied three-quarters of U.S. imports with 5.6 million bags, but by 1919 that figure had fallen to 4.3 million, while Colombia’s share had risen from 687,000 to 915,000 bags. During the same period Central American exports to the U.S. had risen from 302,000 to 1.2 million bags.

In spite of political turmoil, social upheaval and economic vicissitude, the 20th century saw an essentially continuous rise in demand for coffee. U.S. consumption continued to grow reaching a peak in 1946, when annual per capita consumption was 19.8 pounds, twice the figure in 1900. Especially during periods of high global prices, this steadily increasing demand lead to an expansion in production throughout the coffee-growing regions of the world. With the process of decolonisation that began in the years following the Second World War, many newly independent nations in Africa, notably Uganda, Kenya, Rwanda and Burundi, found themselves in varying degrees dependent on coffee export revenue.

For US coffee drinkers, the country’s wettest city, Seattle, has become synonymous with a new type of café culture, which, from its birth in the 1970s, swept the continent, dramatically improving the general quality of the beverage. This new found 'evangelism' for coffee has spread to the rest of the world, even to countries with great coffee traditions of their own, such as Italy, Germany, and Scandinavia, adding new converts to the pleasures of good coffee. Today it is possible to find good coffee in every major city of the world, from London to Sydney to Tokyo; we are drinking more and, more importantly, better coffee.

The importance of coffee to the world economy cannot be overstated. It is one of the most valuable primary products in world trade, in many years second in value only to oil as a source of foreign exchange to producing countries. Its cultivation, processing, trading, transportation and marketing provide employment for hundreds of millions of people worldwide. Coffee is crucial to the economies and politics of many developing countries; for many of the world's Least Developed Countries, exports of coffee account for more than 50 percent of their foreign exchange earnings. Coffee is a traded commodity on major futures and commodity exchanges, most importantly in London and New York.