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.
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.
Flavor 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. Materials
- odoriferous materials such as flowers, spices, pine needles or chips, sage and mint leaves, and fruits (Caution! Not all of these materials are edible, so stick to fragrance, not taste.)
- hot water
- mortar and pestle
- small beaker
- filter paper
- medicine droppers
- small screw-top bottles for storing the extracts
1. Using the mortar and pestle, grind the material you are testing into a pulp. 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?