Where to Find Low-Caffeine Coffee_How Decaf Coffee Beans Are Made_How Much Does a Cup of Decaf Coffee Cost

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Understanding Decaf Coffee

Decaf coffee refers to coffee with only trace amounts of caffeine. The caffeine content in brewed decaf coffee should not exceed 0.3%. This means that one cup of decaf coffee contains no more than 5mg of caffeine (while a regular 236ml cup of coffee typically contains 50mg to 200mg of caffeine). According to the US Food and Drug Administration (FDA) standards, decaffeinated coffee must have at least 97% of its caffeine removed, while the European Union standard requires a 99.9% caffeine removal rate.

Caffeine is a fascinating substance, and you often consume it unknowingly in daily life. Hot chocolate in winter, energy drinks after exercise, and even the refreshing Coca-Cola all contain certain amounts of caffeine. Caffeine has the effect of stimulating the central nervous system and temporarily restoring physical stamina, which sounds like gaining a buff. In fact, caffeine, or 1,3,7-trimethylxanthine, is a xanthine alkaloid compound.

In clinical settings, caffeine is often used to treat neurasthenia and revive patients from coma. In nature, most plants contain this substance as part of their self-protection mechanism - insects become paralyzed after consuming caffeine. Similarly, for humans, there's an upper limit to daily caffeine intake, especially for pregnant women, people with cardiovascular and cerebrovascular diseases, teenagers, individuals sensitive to caffeine, and... young women during their menstrual periods, who should all try to reduce caffeine intake. However, coffee is often called the only legally permitted drug largely because of caffeine. While discussing toxicity without considering dosage is meaningless, even normal populations can experience heart palpitations, stomach cramps, or even caffeine poisoning when consuming excessive amounts. In this context, decaf coffee emerged to meet these needs.

Decaf coffee beans are truly a blessing for those who cannot consume caffeine, proving that food lovers' wisdom should not be underestimated. However, decaf coffee also comes in natural and artificially processed varieties. Natural decaf varieties are extremely rare, with Laurina being one example. In 2004, Brazilian scientists announced the discovery of three other precious decaf coffee varieties in the Kafa forests of Ethiopia, meaning that in the near future, we may be able to drink coffee with naturally low caffeine content.

History of Decaffeination

The first person to extract caffeine from coffee was Friedlieb Ferdinand Runge, but he didn't conduct further research or commercialize it.

The first to commercialize decaffeination was German Ludwig Roselius, who invented a decaffeination method with colleagues in 1903 and patented it in 1906. However, because their method used benzene as a solvent, this method is basically no longer used today.

Decaffeination Methods

1. CO₂ Processing Method

For artificial processing, there are currently three methods for removing caffeine from green coffee beans, but unfortunately, almost none can be performed at home. The first is the technology-driven supercritical carbon dioxide processing method, which can achieve 96-98% caffeine removal efficiency, making it the most efficient (though expensive) processing method.

Supercritical carbon dioxide, which is less extreme than extremely high concentrations, has a density close to that of liquid but remains in a gaseous state, thus possessing gas viscosity. Think of it like a summer night where there was originally only one mosquito buzzing in your mosquito net, but suddenly 300 mosquitoes appear - the density of mosquitoes greatly increases. Although their flight speed might decrease, the reduction won't be significant. Similarly, high-concentration carbon dioxide acts like hungry mosquitoes, and your delicious body represents the caffeine being captured. Blankets, mattresses, and pillows are other chemical components and flavor factors in coffee beans. At this point, coffee beans in pure water solution have already expanded, and tightly bound caffeine molecules are in a loosened state, just like when you kick off your blanket because you're too hot while sleeping. Carbon dioxide molecules rush toward caffeine molecules, combining with them and dissolving into the pure water solution. The processed green beans only need drying to retain most of their flavor. The caffeine extracted by carbon dioxide can be considered 100% pure caffeine and can be recovered through separation operations. Since carbon dioxide is also part of atmospheric components, exhaust gas can be directly released into the air. Carbohydrates, proteins, and various flavor factors in coffee beans are preserved, with extremely high extraction efficiency. The disadvantage, of course, is the cost.

2. Solvent Extraction Method

The second method is solvent extraction. This principle may sound obscure and difficult to understand, but it has long been deeply integrated into daily life. For example, when washing dishes, the stubborn grease in bowls can be dissolved and contained by the lipid components in dish soap, making it easy to clean with water. Caffeine is an alkaloid, and chloroform, which we often call chloroform, is typically used to extract penicillin, essential oils, and alkaloids, making it suitable for extracting caffeine from coffee beans.

Because purine itself has a structure similar to benzene rings, only with N atoms replacing them to form heterocyclic compounds, benzene solutions can also be chosen for extraction.

There are two types of solvent extraction methods. The direct extraction method first uses steam to open the pores of coffee beans, then uses appropriate solvents to dissolve the caffeine, and finally uses steam to carry out both the solvent and caffeine together. It's simple and crude but effective. The other is called indirect extraction, which first soaks green beans in hot water to dissolve various chemical substances from the beans into the water, then adds solvent. Caffeine combines with the solvent and floats to the liquid surface. The separated solvent is then separated from the decaffeinated liquid below, and the processed green beans are soaked in the filtered liquid to ensure coffee flavor factors are preserved as much as possible. The method of treating green coffee beans with solvents is the least expensive, but whether it's chloroform or benzene solutions, they have certain toxicity, and waste liquid treatment is difficult. The operation process is troublesome, and combined with the lowest decaffeination efficiency among the three methods, it has basically been eliminated today.

3. Swiss Water Processing

The most widely used decaffeination method in the coffee industry today is the Swiss Water Process. First, a batch of green beans is soaked in a high-pressure environment to dissolve as many flavor substances as possible into the water. This batch of beans is discarded, and then activated carbon is used to extract caffeine from the soaking liquid. The same batch of green beans is then soaked in the caffeine-extracted soaking liquid. This is like pouring 75% concentrated salt water into 25% salt water, eventually reaching an average 50% concentration harmony in the solution. Since only the caffeine component is missing, caffeine from the green beans spontaneously dissolves into the soaking liquid while preserving other flavor factors in the beans. This method is relatively simple to operate, waste liquid treatment is not troublesome, produces almost no pollution during the process, and can process coffee beans in large batches, making it the most commercially used method today.

However, this processing method also has obvious drawbacks. First is waste - the beans used to extract the soaking liquid can no longer be used for production, resulting in high costs for decaf coffee beans and persistently high prices. Second is the activated carbon extraction of caffeine. Activated carbon is a very powerful substance that can effectively filter and deodorize, such as in tap water purification, bamboo charcoal masks, and bamboo charcoal deodorizing shoe inserts that concerned mothers place in teenage boys' sports shoes... If it can absorb the hormones of restless teenage boys, caffeine is certainly no challenge. Even if some special methods are used to specifically extract and filter caffeine, it still carries away some flavor factors, largely causing the flavor of decaf coffee to be less than satisfactory.

The decaffeination process targets green coffee beans rather than roasted beans. The most difficult part of the decaffeination process is how to remove caffeine without affecting other substances in coffee, such as sugars, cellulose, proteins, citric acid, and fruit acids.

Coffee itself contains over 1000 compounds, and it's these compounds that create coffee's varied layers and aromas. However, no matter which processing method is used, it will more or less affect the coffee's flavor. As the saying goes, there's always a trade-off, but this still doesn't stop coffee lovers from their passion for coffee, right!

FrontStreet Coffee: A roastery in Guangzhou with a small shop but diverse bean varieties, where you can find various famous and lesser-known beans, while also providing online store services. https://shop104210103.taobao.com

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