November 10, 2022

How is decaf coffee made?


Although many people around the world drink coffee to increase their caffeine intake, a significant proportion of coffee drinkers opt for decaffeinated or low-caffeine coffee. In fact, according to Transparency Market Research, the value of the global decaf coffee market is predicted to reach US $14.83 billion by 2031.

The first decaffeination process was used almost 120 years ago by German coffee merchant Ludwig Roselius. In 1903, he created the first commercial batch of decaf coffee. Since then, decaffeination methods have evolved and changed significantly – and now, there are a range of new techniques available.

To learn more, I spoke to two coffee professionals. Read on for more of their insight into different decaf processes.

You may also like our article on what roasters need to know about decaf coffee.

A roaster conducts green coffee quality control

The origins of decaf coffee

Around the world, one of the main reasons that people drink coffee is for the caffeine within.

Caffeine stimulates the central nervous system, which helps to heighten cognitive function, alertness, and mood. However, while many consumers enjoy these side effects, others prefer to reduce their caffeine intake. Some people may even completely remove caffeine from their diet for health reasons. 

To address these concerns, the coffee industry has developed a number of decaffeination processes over the years.

After Ludwig Roselius created the first batch of commercial decaf coffee in 1903, he began selling it through his trading company Kaffee HAG. Three years later, Roselius – along with Karl Wimmer and Johann Meyer – issued a US patent for “the treatment of coffee”.

Their decaffeination technique involved steaming green beans in brine and then dissolving caffeine with benzene – which has now been found to be carcinogenic.

Since then, more food-safe decaffeination methods have been developed. However, it’s important to note that decaf coffee isn’t completely caffeine-free, as some trace amounts may still remain after processing.

To be certified as a decaf coffee, no less than 97% of the caffeine content must be removed. According to European standards, however, a coffee should have 99.9% of its caffeine removed.

Friso Miguel Spoor is a co-founder of green coffee importer The Coffee Quest in the Netherlands. 

“In the past, decaf coffee was mostly commercial-grade, [and therefore likely to be lower in quality],” he says. 

Although decaffeination first emerged at the turn of the 20th century, it became especially popular a few decades later – perhaps most notably during the 1980s.

However, in recent years, the demand for higher-quality decaf coffee has been increasing.

“Over the last five years, there has been a growing market for better-quality decaf coffee,” Friso tells me. “Consumers want a high-quality decaf coffee that tastes as good as other non-decaffeinated specialty coffees.”

He adds that decaf coffee accounts for around 2% of the Coffee Quest’s total coffee sales.

“We have a Brazilian decaf coffee that sells well, but our Colombian decaf coffee has a slightly higher price point because it’s higher quality,” he explains.

Tanks used for decaf processing

Different decaf processes

Since the early 1900s, several different decaffeination processes have been developed in order to remove caffeine.

Chemical solvents

In the past, one of the main ways of removing caffeine from green coffee was by using chemical solvents – mainly methyl chloride or ethyl acetate.

A mixture of water and the synthetic solvent (which is designed to closely mimic the chemical structure of coffee without caffeine) is applied either directly or indirectly to the green beans.

The direct method is when green coffee is continuously steamed and then rinsed with the solvent for up to ten hours, before being drained and steamed to remove any solvent residue. 

The indirect method, meanwhile, involves soaking green coffee in hot water for several hours, before removing it and adding the solvent.

However, it’s important to note that fewer and fewer decaf coffee companies are using methyl chloride as a solvent because of its potential toxicity if consumed in high amounts. That said, according to the US Food and Drug Administration, trace amounts of methyl chloride are safe to consume.

The Swiss Water process

First developed in Switzerland in the 1930s, the patented Swiss Water process has been in commercial use since the 1970s.

The Swiss Water process uses fresh water containing soluble compounds from green coffee (apart from caffeine which is removed using a carbon filter). This mixture is referred to as green coffee extract (GCE).

Green coffee is then soaked in this mixture for up to ten hours, allowing the caffeine compounds to transfer from the green beans to the GCE – leaving around 0.01% caffeine content.

For specialty coffee professionals, the Swiss Water decaf method is perhaps the most well-known, as it is believed that it preserves most of the coffee’s inherent characteristics. Moreover, it’s one of the safest and most natural ways of removing caffeine from green coffee.

Alternative water processes

While the Swiss Water process may be the most common water process, other companies have developed their own methods of removing caffeine by using water.

In 1987, Mexican company Descamex developed a patented water process using osmosis and carbon filtering technology, which is known as the Mountain Water Process.

Luis Demetrio Arandia Muguira is the General Manager at Descamex.

“The caffeine extraction principle is similar to other water processes, but we change many different variables throughout,” he says.

With this process, green coffee is steamed and submerged in a caffeine-free green coffee extract, but variables such as water flow, temperature, and pressure are changed to achieve the best results. Once the green beans reach the required caffeine content, they are triple-dried and cleaned.

“Our main goal is to preserve the original characteristics of the coffee as much as possible,” Luis tells me. 

He adds that some roasters who have purchased Descamex decaf coffee have found flavour notes of tobacco, malt, and caramel as being present in the final roast. However, Luis emphasises that this ultimately depends on a number of factors, including origin and roast profile.

A roaster places green coffee beans into jute bags

Carbon dioxide method

One of the other prominent decaffeination techniques is the carbon dioxide method.

With this process, green coffee is soaked in liquid carbon dioxide at a pressure of up to 300 atmospheres. 

“Because the carbon dioxide method occurs at such a high pressure, it’s known as the ‘supercritical’ process,” Luis says. “As a result of the high pressure, carbon dioxide turns to liquid, which helps it to retain more caffeine.”

In turn, the liquid carbon dioxide either absorbs caffeine compounds and evaporates, or is passed through a charcoal filter to remove the remaining caffeine. 

Friso tells me that when he has tasted decaf coffees which have undergone the carbon dioxide process, results have been promising.

“The intensity of the body was slightly lower, but the mouthfeel was prominent,” he says. “One of the coffees, which was a Colombian from Huila La Victoria, tasted slightly floral and had a delicate acidity.

“The process certainly changed the flavour profile somewhat, but it was still sweet and received good feedback from customers,” he adds. “We also had a Brazilian decaf coffee which was processed using the carbon dioxide method, which remained sweet, too.”

Despite the promising results, this technique is more energy-intensive, which means that the growth of this process has been comparatively quite slow.

Luis tells me: “The high pressure could adversely affect certain kinds of coffees, but it could also benefit other types.”

The sugarcane method

One of the newer emerging trends in decaf processing is the sugarcane method.

As mentioned previously, ethyl acetate – which is a natural derivative of sugarcane and certain fruits – is a solvent used to remove caffeine.

“More recently, we have seen more and more suppliers using the sugarcane method, which is mainly carried out in Colombia,” Friso explains.

One of the pioneers of this process is Descafecol, a Colombian company which uses natural ethyl acetate extracted from local sugarcane. The extract is mixed with spring water, which the green beans are added to under gentle heat and pressure.

Descafecol says many of its clients have scored its decaf coffee more than 85 points on the Specialty Coffee Association grading scale.

“In terms of physical appearance, the coffee looks different, but on the cupping table, you can’t really tell a difference in flavour,” Friso says. “The acidity was still bright and prominent in the specialty decaf coffees, but these are only the coffees we have cupped so far.”

A barista grinds coffee into a portafilter

Looking to the future

Luis tells me that demand for decaf coffee is certainly growing.

“We have noticed three prominent trends in the decaf market,” he says. “Firstly, the increase in home coffee consumption because of Covid-19 has led people to drink more decaf.

“There is also a greater awareness of caffeine intake from consumers,” he adds. “Lastly, a greater range of markets are starting to drink more decaf coffee.”

Ultimately, more and more consumers are demanding higher-quality coffee – and decaf is by no means the exception. Furthermore, while it has historically had a reputation for being lower quality, this has started to change in recent years.

For example, in 2019, Canadian Barista Championship competitor Cole Torode placed third in the World finals using a decaf Gesha variety, which was processed using the Swiss Water method. This is certainly a sign that quality has improved.

Alongside this, we’ve also seen a number of low-caffeine coffee varieties emerge in recent years. Laurina is one of the most prominent examples (containing as little as 0.2% to 0.3% caffeine), while others include Coffea charrieriana from western Cameroon and an arabica variety known as AC1, which was discovered in Ethiopia.

A roaster conducts quality control on decaf coffee beans

There’s no doubt that the decaf market segment has come a long way since its emergence in the early 20th century, with a number of new techniques developed in the years since. And with the market certainly expected to grow in the coming years, we could well see more methods and processes become more readily available.

With that said, the recent growth of low-caffeine coffee varieties could well affect the future of the decaf coffee market – but precisely how it will do so remains to be seen.

Enjoyed this? Then read our article on whether low caffeine coffee varieties could replace decaf.

Photo credits: The Coffee Quest, Descamex

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