Decaffeination is the act of removing caffeine from coffee beans, cocoa, tea leaves and other caffeine-containing materials. Despite removal of most caffeine, many decaffeinated drinks still have around 1–2% of the original caffeine remaining in them, and research has found that certain decaffeinated coffee drinks can contain around 20% of the original caffeine. In the case of coffee, various methods can be used.

Decaffeinated coffee is also referred to as decaf.

Coffee was first successfully decaffeinated in 1820 by German chemist Friedlieb Ferdinand Runge. However, decaf coffee wasn’t commercially employed until 1902, when German Merchant Ludwig Roselius accidentally decaffeinated some coffee beans and subsequently patented, marketed and sold decaf coffee.

There are three main methods of decaffeination.

The original method, known as the Roselius method, involves soaking coffee beans in a chemical, such as benzene, in order to extract the coffee. Benzene has since been shown to be potentially harmful to health if consumed in large quantities and so has been replaced by other chemicals, predominantly dichloromethane and ethyl acetate. This method is still the most popular because it is cheap and it retains most of the original flavors and properties from the coffee.

The second method of decaffeination is is known as the Swiss Water Method which uses solely water and osmosis to decaffeinate the beans. Although this method is healthier and more natural, it hasn’t been such a popular method because it also typically removes some of the other properties and flavors from the bean. This method is typically used for all decaf organic coffee.

The third main method of decaffeination is the Carbon Dioxide or ‘natural’ method. This method dissolves CO2 in water to decaffeinate coffee beans. The CO2 method was invented most recently and is the most expensive method of decaffeination.