How is coffee decaffeinated?
What is Decaf Coffee?
Decaf coffees are coffees that have had most of its caffeine content removed via a process of decaffeination. Various decaffeination methods are used today, each aiming to preserve the flavours and aromas of the coffee while removing the caffeine. These are complex processes that require large specialist equipment, and therefore take place at only a few locations around the world. The raw green coffee is shipped from coffee origins to these locations, decaffeinated, and then transported onwards to the consuming country for roasting.
How Much Caffeine in Regular Coffee vs. Decaf
It is not possible to remove all the caffeine from coffee, so Decaf coffee still contains a small amount of caffeine. This is typically around 0.1% by weight, compared to the regular 1.2% caffeine in Arabica Coffee. As an approximation a cup of decaf coffee will have approximately 10% (or a bit less) of the caffeine in a regular cup of coffee.
The caffeine content in a cup of coffee can varies depending mainly on the type of coffee (species and variety) and brewing method. Using a standard variety of Arabica coffee, a typical double espresso may have 125mg of caffeine, and a typical filter coffee may have 195mg caffeine. For the decaf equivalent there will be approximately 6-12g caffeine in the espresso, or 10-20g caffeine in the filter coffee.
Although decaf is not entirely caffeine-free, the amount present is usually low enough to prevent most of the stimulating effects associated with regular coffee. Decaf coffee is ideal for those sensitive to caffeine, or for coffee lovers to drink late in the day without impacting sleep. Decaf can also be useful for certain people who should be limiting their caffeine consumption for their health – for example pregnant and breastfeeding women.
A Brief History of Decaf
Coffee was first decaffeinated commercially in the early 1900’s by a German coffee merchant Ludwig Roselius. He used benzene as a direct solvent to strip the coffee of its caffeine, which was sold by his brand Kaffee Hag. Although effective, benzene was later found to be toxic, and its use in decaffeination was discontinued.
After benzene, Methylene Chloride (MC) became a popular chemical solvent to decaffeinate coffee. The solvent would remain present in only trace amounts in the end product, below government health guidelines. In the UK the amount of Methylene Chloride allowable as residual in decaf coffee is 2 parts per million. Although still a legal method to decaffeinate coffee the method has become less popular as more natural alternatives have developed. There has been a renewed push in 2024 particularly in the United States to ban this method of decaffeination.
A naturally occurring solvent Ethyl Acetate has become a popular alternative as it is a naturally occurring substance that is consumed daily in a wide variety of foods.
Other non-solvent methods for decaffeination are now available. The Swiss Water Process was developed in the 1930s in Switzerland but not used commercially until the 1980’s by Swiss Water Decaf, based in Canada. This method soaks the coffee in a green coffee extract that draws the caffeine from the beans through a process of diffusion.
The Swiss Water Process
The Swiss Water Process is one of the most popular methods for decaffeinating coffee, popular due to its strong brand name and for being chemical-free.
It involves soaking green coffee beans in hot water, which opens the beans’ pores and allows the caffeine to dissolve. The coffee is then added to a liquid green coffee extract – pure water + all the water soluble contents in coffee, except for the caffeine. This causes the caffeine to migrate to the GCE by a process of diffusion. The GCE is constantly refreshed and renewed, and the diffusion is continued until the coffee is 99.9% caffeine free.
We find coffees that have been decaffeinated to be decaffeinated by the Swiss Water Process to taste very balanced and clean with a moderate body. Our DECAF ETHIOPIA Shakisso and DECAF COLOMBIA Excelso have undergone Swiss Water Decaffeination.
The Sugarcane EA Process
The Sugarcane Ethyl Acetate (EA) process, is a popular decaffeination method in Colombia, where sugarcane is readily available. This process uses ethyl acetate, a naturally occurring compound in fruits and vegetables, as a solvent to remove caffeine. The EA compound is derived from sugarcane, making this method both cost-effective and relatively natural compared to other direct solvent methods.
The process begins by steaming the green coffee beans, increasing the coffees porosity. The beans are then soaked in an ethyl acetate solution, which binds to the caffeine molecules and draws them out of the beans. The liquid in the tanks is repeatedly refreshed until sufficient caffeine has been removed from the beans. After the caffeine is extracted, the beans are steamed again to remove any residual ethyl acetate.
The Sugarcane EA process is known for preserving the flavor and aroma of coffee, as the gentle process avoids extreme temperatures and harsh chemicals. Since the ethyl acetate is naturally derived, and decaffeinated often occurs in the coffee producing country (as is the case with our El Vergel decaf) this method is popular among consumers looking for a decaf option with a lower environmental impact.
We find coffees that have been decaffeinated by the Sugarcane EA process to taste bold and fruity clean with a full body and silky mouthfeel. Our DECAF COLOMBIA El Vergel has undergone Sugarcane EA decaffeination at Descafecol, located less than 100 kilometres from the farm where the coffee was grown.
Other Decaffeination Processes
In addition to the Swiss Water and Sugarcane EA processes, another popular modern decaffeination process is the Carbon Dioxide (CO₂) method.
Like all decaffeination processes, this method begins by soaking the coffee beans in water to expand them and make caffeine extraction easier. CO₂ gas is then applied at high pressure transitioning it into a supercritical state, which means it exhibits properties of both a liquid and a gas. In this state, CO₂ can selectively target and dissolve caffeine molecules while leaving other compounds that contribute to flavor intact.
The caffeine-laden CO₂ is then filtered out through a charcoal filter, where it separates from the caffeine. Afterward, the CO₂ is recycled back into the process, and the caffeine by product is collected to be sold for other uses.
Is Decaf Coffee Safe?
Decaf coffee is considered safe for consumption - modern decaffeination processes have eliminated the need for toxic chemicals like benzene, which was used in the early iterations of decaf. Today’s methods, such as the Swiss Water Process and the Sugarcane EA Process, rely on natural solvents or water, ensuring minimal chemical exposure. Research has consistently shown that these decaf coffees poses no known health risks and retains most of the beneficial antioxidants and other compounds found in regular coffee.
Decaf coffee offers a safe and enjoyable alternative for those looking to reduce caffeine intake without sacrificing the joy and flavour experiences of a coffee ritual. Great decaf means that coffee lovers can enjoy a flavourful, aromatic cup with only a fraction of the caffeine of a regular coffee. Ready to try some great decaf – explore our decaf options here.
References
- Ramalakshmi, K., & Raghavan, B. (1999). Caffeine in Coffee: Its Removal. Critical Reviews in Food Science and Nutrition, 39(5): 441-456.