Instant coffee, also called soluble coffee and coffee powder, is a beverage derived from brewed coffee beans. Instant coffee is commercially prepared by either freeze-drying or spray drying, after which it can be rehydrated. At least one brand of instant coffee is also available in concentrated liquid form.
Advantages of instant coffee include speed of preparation (instant coffee dissolves instantly in hot water), lower shipping weight and volume than beans or ground coffee (to prepare the same amount of beverage), and long shelf life—though instant coffee can also spoil if not kept dry.
History
Instant coffee was invented in 1901 by Satori Kato, a Japanese scientist working in Chicago. Kato introduced the powdered substance in Buffalo, New York, at the Pan-American Exposition.[1] George Constant Louis Washington developed his own instant coffee process shortly thereafter, and first marketed it commercially (~1910). The Nescafé brand, which introduced a more advanced coffee refining process, was launched in 1938.
High-vacuum freeze-dried coffee was developed shortly after World War II, as an indirect result of wartime research into other areas. The National Research Corp. was formed in Massachusetts as a process-development company employing high-vacuum technology. It developed high-vacuum processes to produce penicillin, blood plasma and streptomycin for US military use. As the war ended, NRC looked to adapt its processes for peacetime uses. It formed Florida Foods Corp. to produce concentrated orange juice powder, and originally sold its product to the United States Army. That company later changed its name to Minute Maid.
Use
One advantage of instant coffee is its simplicity of preparation. It is virtually impossible to spoil the product accidentally during the rehydration process, and simple instructions are printed on the back of typical instant-coffee packaging.
Instant coffee is available in powder or granulated form contained in glass jars, sachets or tins. The user controls the strength of the resulting product, by adding more or less water (for a weaker or stronger brew).
Instant coffee is also convenient for preparing iced coffee like the Greek frappé, which is popular in warmer climates and hot seasons.
In some European countries such as Spain, instant coffee is commonly mixed with hot milk instead of boiling water.
Production
As with regular coffee, the green coffee bean itself is first roasted to bring out flavour and aroma. Rotating cylinders containing the green beans and hot combustion gases are used in most roasting plants. When the bean temperature reaches 165 °C the roasting begins, accompanied by a popping sound similar to that produced by popcorn. These batch cylinders take about 8–15 minutes to complete roasting with about 25-75% efficiency. Continuous fluidized bed roasting only takes between thirty seconds and four minutes, and it operates at lower temperatures which allows greater retention of the coffee bean aroma and flavor.
The beans are then ground finely. Grinding reduces the beans to 0.5–1.1-millimetre (0.020–0.043 in) pieces in order to allow the coffee to be put in solution with water for the drying stage. Sets of scored rollers designed to crush rather than cut the bean are used.
Once roasted and ground, the coffee is dissolved in water. This stage is called extraction. Water is added in 5-10 percolation columns at temperatures of 155 to 180 °C; this concentrates the coffee solution to about 15-30% coffee by mass. This may be further concentrated before the drying process begins by either vacuum evaporation or freeze concentration.
