|Where does coffee come from? How is it processed? How does it fit into human culture?|
How does a coffee bean become a cup of java?
David follows a coffee bean from plantation to mug.
Segment length: 6:00
It's been used as a medicine and an ingredient in wine. It's been linked with revolutionary ideas. First a food, later a beverage, coffee contributed significantly to the economic health of countries that controlled it. The coffeehouses in the Middle East and Europe that sprang up because of it became centers of intellectual ferment, often frowned upon by the authorities.
Native to Ethiopia, this crop is now grown around the world and is a major commodity in the world economy. The principal species, Coffea arabica, thrives at high elevations in a moist, mild climate where there is partial shade. That's why most of the big coffee producers are located in mountainous countries near the equator.
The coffee tree is a shrublike plant with glossy, dark-green leaves and small, white, fragrant flowers. The fruit, or cherry, is initially green and gradually ripens to a dark red. Although people used to eat the coffee cherries or chew the coffee leaves, the principal interest now is in the coffee seeds or beans.
Removal of the fruit from the beans requires several steps and considerable water because the inner part of the fruit is so sticky. Processors first pulp and wash the cherries, and then allow them to ferment before washing them again. During fermentation, microorganisms act on the sticky inner layer of the cherry to break it down. Finally, the seeds are dried, and a hulling machine crushes the remaining parchment covering so it can be removed. The seeds-now called green coffee beans-can be roasted in several different ways.
To prepare coffee, people brew the ground-roasted beans with hot water, a process that extracts flavor and fragrance chemicals. Only those chemicals that are soluble in hot water dissolve to make the coffee. The coffee grounds are left behind. One chemical naturally present in coffee is caffeine, which is a mild stimulant. But many different chemicals are manufactured by the coffee plant, and other chemicals are created in the roasting process.
Most coffee flavor comes from roasting-green coffee beans smell and taste completely different from roasted ones. Caffeine can be extracted from the beans to make decaffeinated coffee without altering the flavor much, since caffeine itself has very little flavor.
1. If you were a farmer, what things would you consider before growing
coffee for sale? What plans would you have to make?
2. What are the known effects of caffeine on the human body? Is caffeine addictive? Are there medicinal uses for it? Do soft drinks with caffeine sell better than those without?
brewing hot-water extraction of flavors, fragrances, and caffeine from ground-roasted coffee beans
commodity any object or material that is bought and sold
economic botany the study of plants bought, sold, traded, or otherwise involved in a society's commerce
fermentation in coffee processing, the action of microorganisms on the sticky inner pulp of coffee cherries
hulling removal of the dry parchment layer on coffee beans after they have been pulped, fermented, washed, and dried
pulping mashing coffee cherries to loosen the fruit pulp so it can be washed away
roasting heating green coffee beans in hot air to brown them and develop the distinctive aroma and flavor of coffee
Additional source of information
National Coffee Association
110 Wall Street
New York, NY 10005
(Free history booklets on coffee-requests in writing only.)
Extract and blend fragrances to make one that appeals to you.
Flavors and fragrances play a large part in our daily lives. We add spices to food to make it taste and smell good, and put perfume on ourselves to make us more attractive. We tend to avoid unpleasant odors. Most flavors and fragrances are not single chemicals but mixtures of several substances. Coffee is usually blended from various types of beans to obtain a pleasant taste. Experienced coffee tasters can tell where specific kinds of coffee come from just by taste.
and fragrance experts talk about "notes" of scent-fruity, flowery,
aromatic, earthy, musky, and so on. Some odors are unpleasant in large
amounts, but smell good in small amounts or when mixed with other scents.
Coffee, for example, contains sulfur compounds that are unpleasant by themselves,
but that smell pleasant in the aroma of coffee. Most perfumes are specific
blends of fragrance notes.
1. Using the mortar and pestle, grind the material you are testing into
2. Place the material in the beaker and soak with hot water. Be careful when handling the hot water.
3. After stirring the material in the hot water, set up the funnel with filter paper. Pour the mixture into the filter paper and collect the filtrate (extract) in a screw-top bottle. Label the bottle with the source of the extract. Manufacture as many different extracts as time allows.
4. Mix small portions of various extracts to make new fragrances. Experiment with a variety of combinations. Can you design your own personal fragrance with particular "notes"?
5. Health food stores often sell essential oils from various plants. What other scents would you like to obtain to add to your mixture?
Many foods and drinks contain caffeine. Find out what they are and add up your daily caffeine consumption.
Too much caffeine makes people jittery and irritable. In larger quantities it can be poisonous. Decaffeination removes the caffeine from coffee and other beverages. One type uses carbon dioxide under so much pressure that it becomes a semi-liquid called a supercritical fluid. Find out about other decaffeination processes. How will you plan your research?
Try your hand at economic botany. By studying back issues of the Wall Street Journal, Business Week, or other financial publications, track the weather in Brazil and the price of coffee. Can you graph these two things on a yearly or semi-annual basis? Does there seem to be a relationship between weather and price? What other environmental events might influence the price of coffee or other commodities?
A fruit is the enlarged ovary of a flowering plant, and it encloses the seeds from which a new plant can grow. Coffee cherries are fruits, and fruits all have some similarities. Dissect several fresh fruits. How are they different? How are they similar? Could you tell plants apart based entirely on their fruits?
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