Decaffeinated Coffee |
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Decaffeinated Coffee |
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Decaffeinated coffee is not really a
coffee of convenience, but for people who do not want the effects of
the caffeine, to have a sort of unleaded version of it at their
fingertips is handy, to say the least. Caffeine as a substance had
been discovered and was known to be in coffee years before
decaffeination was practiced. The eighteenth-century German writer
Goethe supposedly took some coffee beans to a chemist friend, who
analyzed the contents and reported on the power source within. It
was not until 1906, however, that Ludwig Roselius of Bremen, with
the help of Frederick Ringe, discovered that caffeine is
water-soluble. The result of his labors was Kaffee Hag, the first
company to specialize in decaffeinated coffee. Many people find that coffee upsets their stomach, so they assume they should be drinking decaffeinated coffee. Coffee contains acidity; and some coffees are more acid, particularly those blends with high-grown South and Central American coffees, and they are even more so if the coffee is not very dark roasted. When coffee is decaffeinated it does not lose its acidity, and it is probably the acidity that is causing the stomach problem. The solution might be to drink "acid-neutralized" coffees, which are hard to find, but they are out there. The good news is that decaffeinated coffee, which used to taste as though it had been filtered through a newspaper, is now almost indistinguishable from the real thing. In fact, blind tastings of beans from the same bags, undecaffeinated and treated with different methods of decaffeination, have shown that even expert tasters cannot reliably tell which is which. They sometimes even like the decaf best, and sometime even the coffee decaffeinated by chemical methods. So why is decaffeinated coffee now so good? The actual methods of decaffeination have changed very little over the years, so the difference must be that at last the coffee companies are using good beans in the blend, instead of the (figurative) factory floor sweepings. There are various methods of decaffeinating coffee beans, and most of them treat the unroasted (green) beans. First, depending on the decaffeination method, the green beans are usually steamed. Because green beans are extremely hard, the steam cannot damage the beans; it merely softens them, making their cells a bit more open and vulnerable to soaking. If a water method of processing is to be used, then the beans are soaked either in a solution water and coffee compounds (add to help keep flavor compounds from passing out of the beans), or basically just water (called the Swiss Water Process). When at least 97 per cent (99 percent for Switzerland) of the caffeine has passed into the water, the beans are drained. If the soaking solution was water and coffee compounds, this mixture, now containing the caffeine, is combined with methylene chloride and steamed. The methylene chloride and steamed. The methylene chloride and the caffeine leave the mixture during the steaming, and the cleared mixture goes back to work on the nest batch of beans. If the original mixture was originally just water, after it is laden with caffeine and removed from the beans it is filtered with activated charcoal to remove only the caffeine, leaving any coffee compounds that may have passed into the water. The original soaking water, now caffeine-free, but possibly containing coffee compounds, is reunited with the beans. The decaffeination process most feared by health fanatics is the straight solvent method. The steamed beans are soaked in methylene chloride, which quickly absorbs the caffeine from the beans. When the beans are 97 per cent caffeine-free, the beans are steamed and heated until any residual solvent has evaporated. The important thing to remember is that the beans still have to be roasted, and that is at temperatures of 200-240oC, the US Food and Drug Administration concluded after exhaustive tests that a person would have to drink 11 million cups of solvent-decaffeinated coffee to have a trace of solvent in his body. Another solvent used is ethyl acetate, and although it can be used on liquid coffee, which later will be processed into instant coffee, which later will be processed into instant coffee, the principle is basically the same, even if the process is a bit more convoluted. First the caffeine passes from the liquid coffee into the ethyl acetate, from which it goes into water, from which it is removed and solidified. Meanwhile the "clean" ethyl acetate is recombined with the original coffee to replace any flavor compounds it might still retain; the "clean" water goes on to be used with the next batch of beans. A third method of decaffeination is that of adding carbon dioxide under high pressure to green beans and water, and keeping them at high pressure for several hours, after which beans go on to be roasted, and the carbon dioxide is cleared of caffeine and re-used. |
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