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Coffee Roasting and Grinding


Coffee Roasting and Grinding

Most coffee is roasted in the country where it will be consumed. Most processors blend different types of green beans before roasting. Roasting is performed in revolving, perforated, metal cylinders that are heated by gas or light fuel oil. The older batch roasters operate at about 400° F (200° C) for 16 to 17 minutes. The modern, continuous-process roasters operate at 500° F (260° C) for 5 minutes. A large roaster can turn out 5,000 to 10,000 pounds (2,300 to 4,500 kg) of roasted coffee per hour.

Medium roasts are preferred in the United States. French and Italian roasts are much darker, and Turkish roasts are darkest of all.

The roasted coffee is cooled before grinding. Grinding machines break the whole beans into particles with a series of rollers that produce from 1 to 10 grind sizes at rates up to 4,000 (1,800 kg) pounds per hour. The ground coffee is then packaged in vacuum cans or paper bags in sizes from 1/2 to 3 pounds (0.2 to 1.3 kg).

Soluble (Instant) and Decaffeinated Coffee

The possibility of preparing an extract from coffee was considered as early as 1838, when the United States Congress substituted coffee for rum in the rations of soldiers and sailors. Probably the first powdered instant coffee was invented by Sartori Kato, a Japanese chemist living in Chicago. He first sold his soluble coffee at the Pan American Exposition in Buffalo in 1901. Soluble coffee was first marketed on a broad scale in the United ^tates by the American chemist G. Washington i 1909. However, the demand for the product remained small until World War I when the entire output of all soluble coffee in the United States was purchased by the War Department for troops in the field. During World War II the government bought almost 260 million pounds (118 million kg) of instant coffee. By 1953 one cup of coffee in 10 was instant; a more recent estimate is one cup in five.

Soluble coffee is produced by brewing coffee in a series of giant coffee pots. The extract moves from pot to pot until it reaches optimum strength. Then the water is removed, usually by drying. A spray nozzle atomizes the liquid in a current of hot air. The hollow spherical particles known as "beads" then are packaged.

Decaffeinated coffee is made by several methods; each treats the green coffee to remove the caffeine. The decaffeinization processes provide a major source of caffeine for the chemical and drug industries.

Making Coffee

Each brand of coffee represents a different blend of coffee beans. A brand should be selected for its flavor, and the grind for the type of coffee maker used. For a percolator, use regular grind; for a drip pot, drip or all-purpose grind; for a vacuum style coffee maker, fine grind.

Regardless of the brand, grind, or personal preference as to whether coffee should be full-bodied or light, coffee must be made full strength to obtain optimum flavor. For less than full-bodied brew, dilute the coffee with hot water after making it with the recommended coffee-to-water ratio.

For each serving, use 1 coffee measure or 2 level measuring tablespoons of coffee and 6 ounces of water. Both the coffee and the water should be fresh. Coffee should be purchased in amounts that can be used within a week and should be stored in a tightly closed container in a cool, dry place. Freshly drawn cold water is desirable because the flavor of coffee is sometimes affected by mineral deposits in hot water pipes.

The coffee maker should be clean and should not be used at less than three' fourths of its capacity. If a percolator is used, perk gently for 6 to 8 minutes. If a drip or cone type coffee maker is used, dripping is usually completed in 4 to 6 minutes. In vacuum pots, boiling water that rises into the upper bowl should be allowed

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