What is decaf coffee? Is decaffeinated coffee good?

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The so-called decaf coffee

It means that the coffee beans are processed before they are sent to the roaster to separate the caffeine that affects sleep. However, decaffeinated coffee is not 100% caffeine-free. It can only remove 94% to 98% caffeine and still contains trace amounts of residual caffeine. At present, there are three commonly used low-cause treatment methods, namely, dissolving method, Swiss water treatment method and carbon dioxide extraction method.

Decaffeinated coffee originated from the great German poet Goethe. His brother likes coffee, so he often can't sleep properly, so he asks his chemist friend Runge to analyze what ingredients are in the coffee beans and interfere with sleep. In 1820 Rongi separated the caffeine from the beans and became the ancestor of decaf. However, at that time, the technology could not produce decaf coffee in large quantities, only that the substances that caused insomnia caused by coffee beans could be extracted. It was not until 1903 that there was a major breakthrough in the technology of extracting caffeine and mass production began. This is due to Ludwig Roselius, a German coffee importer, and the chemists who assisted him. Roserus found that once imported raw coffee beans were soaked in sea water, the caffeine content decreased a lot, so he hired a group of chemists to study it and developed a new technology for extracting caffeine.

Solvent extraction method

Roserus is inspired by the loss of caffeine from soaked raw beans. Heat the beans in a high-pressure steam pan. After the beans are looser and softer, add benzene solvent to extract caffeine. Although benzene only chooses caffeine as the extraction object and does not extract other ingredients from coffee beans, benzene is toxic and drinking decaf coffee made by benzene solvent extraction is harmful to health. However, the awareness of health care was very weak at that time, and Roserus founded Kaffee HAG in Germany in 1906, which was the first company to produce decaf in large quantities.

The medical community is gradually worried that the residual benzene in decaf coffee will cause harm to the human body. Chemists have also developed extraction solvents dichloromethane and ethyl acetate without safety concerns. The advantage of dichloromethane is that the boiling point is very low and volatilizes when heated to 40 degrees Celsius. After years of testing, the US Food and Drug Administration (Food and Drug Administration) approved dichloromethane as the legal caffeine extraction solvent in 1985. As for ethyl acetate, it is safer because some fruits contain more ethyl acetate than decaf coffee and are also listed as legal extracts in the United States. Solvent extraction can be divided into direct and indirect methods. However, the pre-operation of the two methods is the same, and they must be softened first, that is, the coffee beans are steamed at high pressure and high temperature, and the bean surface expands, resulting in an increase in contact area with the liquid, and then the dichloromethane or ethyl acetate solvent is added to extract caffeine. This is called the direct method, which is the method used by Roserus. The difference is the extraction solution, which used toxic benzene in the past, and now uses safe dichloromethane or ethyl acetate. Another indirect extraction method is that the coffee beans are softened and placed in warm water, and the caffeine and other ingredients in the beans are dissolved into warm water, where the solution almost becomes a coffee essence, and then into another container. Add dichloromethane or ethyl acetate, extract the caffeine, slightly heat the caffeine will evaporate with the extraction solution. Finally, the non-caffeinated essence is introduced into the coffee beans previously extracted by warm water to reabsorb or replenish the lost ingredients. Generally speaking, indirect extraction will lose more coffee flavor, which is not as ideal as direct extraction.