Starting the workday with a cup of coffee has become a habit for many friends. With the development of the coffee industry, more and more novel coffee processing methods have emerged. In addition to the diversity of processing methods, coffee categories are also becoming increasingly subdivided. One rather special category that Front Street Coffee will introduce today is decaf coffee.For some sensitive individuals, even a little caffeine is enough to cause negative effects, such as being wide awake through a long night. In this case, decaf coffee is a good choice for such sensitive people, or for those who need to quit caffeine. Customers often ask Front Street Coffee: "How was decaf coffee born? Can decaf coffee also be specialty grade? If high-quality coffee beans are made into decaf coffee, will it still taste just as good?" So today, Front Street Coffee will explore with everyone what decaf coffee is.The Story of Decaf CoffeeIt is said that the famous German poet Goethe was also a coffee lover, but he also suffered greatly from being unable to sleep after drinking coffee. The feeling of loving it yet being unable to get close to it led Goethe to seek out his friend Runge(Runge)to analyze the components of coffee beans and find out why coffee interferes with sleep. Around 1820, Runge identified caffeine as the factor affecting sleep and developed a method to separate coffee beans from caffeine, thus making Runge the originator of decaf coffee.Although Runge invented the method of separating caffeine, the method at that time could not achieve mass production of decaf coffee. It was not until 1903 that the German coffee bean importer Ludwig Roselius(Ludwig Roselius)discovered that once coffee beans were soaked in seawater, their caffeine content would decrease significantly. So he asked a group of chemists to research caffeine separation technology from this angle, which led to an important breakthrough in caffeine separation technology. Only from this point on could decaf coffee begin to be mass-produced.Decaf coffee is the abbreviation of coffee without caffeine(decaffeinated coffee). Apart from naturally occurring decaf coffee, there are also many methods to remove caffeine from coffee beans. However, in addition to removing caffeine, depending on the method used, the taste, aroma, and color of the coffee may undergo varying degrees of change.Does decaf coffee bean mean it is completely caffeine-free? Not exactly. Decaf coffee actually only removes about 97% of the caffeine, not all of it. Although caffeine still exists, compared with regular coffee, the effect decaf coffee has on people is extremely, extremely small.The stimulating effect of caffeine can be said to be the main reason people cannot do without it. Caffeine is a central nervous system stimulant. Consuming caffeine can make people less likely to feel tired, and it also has effects such as improving concentration and reducing pain. In fact, decaffeinated coffee was not a demand that only appeared in the 21st century. As early as the beginning of the 20th century, the German coffee company Kaffee Hag had already developed this product(it wasthe world's first company to sell decaf coffee). It was just that at the time, not many people drank decaf coffee. It was not until after the end of World War II that a type of coffee bean with higher caffeine content — Robusta beans(Robusta; Coffea canephora)— rose to prominence, which greatly increased the amount of caffeine many people consumed. Most of the coffee we commonly see in daily life comes from Arabica beans (Coffea arabica), which account for about 60% of global production. Because the coffee brewed from them has diverse aromas and rich flavors, they are mostly made into various specialty coffees. Robusta beans, on the other hand, have a strong smell and bitter taste, so they are often made into blended coffee or instant coffee, and they account for nearly 40% of global production. In addition, Arabica beans contain about 1.2–1.5% caffeine, while Robusta beans contain nearly twice that, about 2.2–2.7%. After World War II, more and more coffee products made from Robusta beans appeared, but because of their high caffeine content, they easily made consumers feel uncomfortable, so many manufacturers began to invest resources in developing decaf coffee products.
Common methods for removing caffeine all use "extraction." Generally, green coffee beans are first extracted to remove caffeine, and then they are dried and roasted. Common extraction methods can be broadly divided into three major categories: solvent decaffeination, carbon dioxide processing, and water processing.Solvent Extraction MethodDepending on the processing steps, solvent extraction can be divided into two types: "direct solvent extraction" and "indirect solvent extraction." Because caffeine binds with chlorogenic acid (CGA) inside the bean, before extraction begins, the dried coffee beans need to be fully saturated with water to separate the two, so that caffeine molecules can be effectively dissolved out.In the direct extraction method, dried green coffee beans are first steamed and soaked thoroughly with water vapor, then the green beans are immersed in solvent. After the caffeine is dissolved out, they are removed and heated so that the solvent and moisture evaporate. In the indirect extraction method, the green beans are boiled in hot water, dissolving out caffeine and various aroma molecules. The water used to boil the coffee beans is then thoroughly mixed separately with solvent so that the caffeine dissolves into the solvent. After removing the solvent, the remaining water is used to rinse the green beans so that the aroma molecules can return to the beans again, and finally they are drained and dried.
Speaking of caffeine extraction solvents, dichloromethane could be said to have dominated the decaf coffee industry before the 1970s and was recognized as the most useful solvent. In addition to its quite good extraction performance, its colorless nature, low boiling point of 39.6°C, easy volatility, and non-flammability made the process quite efficient and safe. But ironically, the reason dichloromethane was eventually abandoned was not because it was found to possibly be carcinogenic, but because at the time it was suspected of being one of the culprits behind the hole in the ozone layer. After dichloromethane fell out of fashion, it was replaced by ethyl acetate. Ethyl acetate is naturally produced in nature, and many fruits themselves contain a certain proportion of it, so there are relatively few safety concerns. In 1982, the U.S. Food and Drug Administration(U.S. Food and Drug Administration, FDA)approved ethyl acetate for decaffeination. However, because many foods contain ethyl acetate, its health effects cannot be directly investigated, so no explicit permitted residue standard was established. Carbon Dioxide Processing MethodThe carbon dioxide processing method is similar to the direct solvent method. Coffee beans are soaked in warm water, and then high-pressure liquefied carbon dioxide replaces the solvent to extract caffeine, after which the carbon dioxide returns to room temperature and becomes gas again. Coffee made using carbon dioxide decaffeination places a lower burden on the human body, and according to research, this method extracts more caffeine than the direct solvent method. However, the cost of this method is much higher than that of the direct solvent method.In addition to the costly supercritical fluid method, at the time another group of people developed a method using water as a solvent that could extract caffeine without losing coffee flavor. This type of method costs much less than the supercritical fluid method and is simpler to operate. The most common water processing method is the Swiss water process developed by the Swiss company Coffex in the late 1970s(Swiss water process). The Swiss water process involves soaking green coffee beans in hot water. The soaking stage actually already removes caffeine to some extent. The soaked solution is then filtered through activated carbon, and finally the solution is returned to the coffee beans. This series of steps removes caffeine more effectively. In addition to not requiring chemical solvents, the soaked solution can also be reused in different batches of processing. However, the coffee still loses a great deal of flavor during the filtration process. The drawback of this processing method is that its production cost is much higher than the two solvent methods mentioned above, and the extracted caffeine is directly filtered out and cannot be used for other commercial purposes. Mountain Spring Water Processing MethodThis uses another special kind of water, water taken from glaciers, to extract caffeine. The company Descamex states that it uses some kind of special filtration device to remove caffeine. After processing, a caffeine-free water-based solution is obtained. This solution also contains dissolved coffee solids and can be reused in the decaffeination process. This processing method, like the Swiss water process, does not use chemical solvents, so some consumers therefore regard it as a safer and healthier choice.Can Decaf Coffee Also Be Specialty Coffee?People often think decaf coffee has a flat and uninteresting flavor, because during processing, in addition to caffeine being removed, the coffee also loses some of its most important flavor substances. Therefore, the biggest challenge faced by companies making decaf coffee is finding a method that can extract caffeine without sacrificing the flavor of the coffee beans. This has always been a highly controversial topic in the specialty coffee world.The most common processing method is to directly remove caffeine with solvent, but this method directly damages the flavor of the coffee, because it is impossible for the removal target to be limited only to caffeine. Those substances that bring deliciousness to coffee are consumed in large amounts during processing, causing a huge impact on coffee flavor. Lower-quality coffee beans often use solvent processing because the beans themselves do not taste very good.But these statements do not mean there is no such thing as decaf specialty coffee. By using good-quality coffee beans and a processing method that causes less flavor loss to remove caffeine, coffee of quite good quality can still be obtained. Decaf coffee beans obtained using the Swiss water process have their flavor damaged to a lesser extent, but its processing cost is higher, so it is less often used to process decaf coffee. The Swiss water process retains the solid dissolved substances of the coffee beans. This technology extracts caffeine through "activated carbon specifically used to filter out caffeine." This step preserves the flavor of the coffee's origin and the flavor of the batch processing, and in order to confirm that the flavor has been retained, cupping is generally conducted after processing to compare before and after.How Should Decaf Coffee Be Roasted?How do you roast decaf coffee so that it has sweetness? The decaf coffee production process includes adding water to green coffee beans to extract caffeine, and then drying them again. During the decaffeination process, it is carried out as gently and carefully as possible, removing caffeine while affecting the flavor as little as possible. This means the structure of the coffee beans will be somewhat different from regular coffee, so a gentler approach is needed during roasting.During roasting, decaf coffee will follow a similar temperature curve, but the rate of temperature rise is a bit different. Because decaf coffee has also undergone decaffeination processing, the degree to which the coffee beans retain heat is also different. Therefore, roasters need to adjust the batch size and boiler preheating time specifically for decaf coffee. A gentler roasting curve than usual is typically used to roast decaf coffee, such as a lower and slower rate of temperature rise, and a curve that gently declines after the rate of temperature rise reaches its maximum until the end of roasting. There are two keys to maximizing sweetness in decaf coffee roasting: extending time and lowering temperature. The goal is slight caramelization before first crack.
When roasting reaches first crack, decaf coffee reacts very differently from regular coffee. Once decaf coffee begins to release heat, development proceeds differently, and the energy maintained in the coffee beans is not very tense. The special cellular characteristics of decaf coffee may pose challenges to the roaster. On the one hand, the beans can easily be over-roasted and over-developed; on the other hand, because they cannot maintain as much heat inside the bean, you cannot simply drop them after roasting like regular coffee and wait for them to cool.So, look for high-quality green beans. Ensure there is enough but not excessive caramelization at first crack, and skillfully manage the roast after first crack to achieve the correct balance of sweetness, acidity, and bitterness. To roast delicious and sweet coffee still requires continuous roasting to accumulate experience. And because decaf coffee has a lower caffeine content, it can indeed effectively reduce the impact on sleep, but the specific situation still varies from person to person~ The above content is compiled by CoffeeHunters, a coffee news website.
