Demystifying Decaf — A Roaster’s Guide to Decaffeination

Caffeine plays a crucial role in coffee. The chemical compound delivers stimulating energy to coffee drinkers and, for the coffee plant itself, it acts as a natural pest repellent. That’s why Robusta coffee plants are heartier and can thrive at lower altitudes. They are naturally more pest-resistant than Arabica plants — i.e., they contain more caffeine.

Coffee is naturally caffeinated, but for people who are sensitive, a dose of 50 to 100 milligrams of caffeine in your average cup of coffee is way too much. (That’s for a single or double espresso-based drink. It can go up to 160 milligrams if the coffee is brewed with long infusions like cold brew or pour overs.) With decaf coffee, around 97% of the caffeine is extracted from the beans using different decaffeination methods, leaving an average of 3 milligrams per cup.

Caffeine is a water-soluble chemical, and the challenge is trying only to target caffeine while leaving other water-soluble elements like sugars and proteins intact to preserve flavor. There are three ways to extract caffeine: with chemical-stripping solvents, liquid carbon dioxide, or water-only processes that gained traction in the 1980s.

Coffee of any process (natural, washed, honey, etc.) can undergo decaffeination, which happens at the green bean stage after removing the parchment. Decaffeination usually occurs in a separate facility, with some of the most well-known ones located in Canada, Mexico, and Colombia.

A Brief History of Decaf Coffee

German coffee merchant Ludwig Roselius discovered how to decaffeinate coffee in the early 1900s. He steamed coffee beans in a brine salt solution and extracted the caffeine with benzene. Unfortunately, we now know this natural solvent is highly toxic and causes cancer, so no one uses the Roselius process anymore. Benzene has since been replaced with other solvents like methylene chloride and ethyl acetate.

Solvent-Based Processes: Indirect vs. Direct

Indirect decaffeination happens when solvents only treat the water where caffeine and other compounds are stripped from the beans. The coffee itself stays separated from the solvent chemicals. Often referred to as the “European process” or “Euro prep,” beans are soaked in boiling water and then removed from the solution. Solvents like methylene chloride or ethyl acetate are then added to the water to bind and remove caffeine compounds. Once the water is decaffeinated, the flavorless beans are reintroduced to the solution and soaked to reabsorb the remaining flavor compounds and oils.

On the other hand, direct decaffeination happens when the coffee beans are directly immersed into solvent-laden solutions. Sugarcane is readily available in Colombia, and its application to the coffee industry was a game-changer. The name might sound like a caustic chemical, but ethyl acetate is an organic compound found in sugarcane, fruit juices, cereals; that’s why it is known as a “natural” decaffeination process. This process begins with the fermentation of molasses derived from sugarcane to create ethanol. This alcohol is then mixed with acetic acid (the main component of vinegar) to create the compound ethyl acetate.

In a direct solvent-based process, low-pressure steam opens the pores of the coffee beans. Then the beans are soaked in a solution of water and ethyl acetate. The solvent binds to the salts of chlorogenic acids and allows the removal of caffeine. After flushing the beans with ethyl acetate repeatedly, up to 97% of the caffeine is extracted. The remaining chemicals are eliminated by steaming the beans again. Because ethyl acetate comes from sugarcane and is an organic compound that can effectively remove caffeine, the coffee’s flavor attributes are not extracted. They will instead be slightly sweeter, thanks to the solvent.

That’s why decaf beans like Genuine Origin’s Valle del Cauca are such a popular alternative to caffeinated coffee. The sugarcane process helps preserve delicious flavors like dried cherry, hazelnut, nougat, and red apple and highlights a pleasant sugary flavor and heavier body.

Carbon Dioxide (CO2 Decaf) Process

One of the most expensive ways to extract caffeine is by using liquid carbon dioxide. Because the CO2 is highly selective for caffeine and requires low temperature and low pressure conditions to maintain its liquid state, the original structure of the coffee beans is left mostly intact. That’s how CO2-processed decaf coffee can retain so much of the coffee’s original flavors and compounds.

The beans are moistened with water and then circulated with the liquid CO2, which draws caffeine out. The caffeine evaporates from the CO2 in another chamber, and the CO2 is pumped back into the beans in a repetitive process until they reach the desired caffeine level. This process is relatively newer but has a high potential for decaffeinating more delicate and high-grade coffee beans. Currently, the process is being used to decaffeinate large quantities of commercial-grade coffee to offset the high cost.

Water-based decaf processes: Swiss Water Process and Mountain Water Process

The Swiss Water Process and Mountain Water Process are both trademarked to facilities in Canada and Mexico. Both are water-only and free from chemical solvents, making them popular natural methods of decaffeination.

The Swiss Water Process, first pioneered in Switzerland, uses a proprietary Green Coffee Extract (GCE) solution, made from soaking coffee in pure water to extract caffeine and other desirable coffee compounds that influence flavor. The GCE is filtered through activated carbon to remove caffeine, leaving behind “flavored” water. The first batch of beans is discarded, but the GCE is kept and flushed through another batch of beans. Because the GCE is now caffeine-free, the caffeine in the new beans automatically extracts itself and migrates into the GCE solution. By repeatedly flushing beans with GCE and filtering the GCE through carbon, the process simultaneously removes caffeine while keeping the beans saturated in flavor-rich water.

When coffee — like the Peru Santo Domingo — goes through the Swiss Water Process, the result is a 99.9% decaffeinated coffee that retains bright acidity and flavors like milk chocolate, green apple, and caramel.

The Mountain Water Process is similar but occurs in the Descamex facility in Mexico. The pure water used in the caffeine extraction solution comes from Pico de Orizaba, the highest mountain in the region, and also results in 99.9% decaffeination. Like the Swiss Water Process, this water-based decaffeination is chemical-free and can therefore retain organic certifications for the original beans.

Decaf Coffee that Doesn’t Disappoint

The discovery of new decaf processes is a good sign for improvements in the quality of decaf coffee. Now, decaf drinkers don’t need to sacrifice flavor for the sake of lower caffeine content, and coffee producers can continue to focus on growing high-grade coffee that complements any changes that happen during decaffeination. Genuine Origin is always on the lookout for delicious decaf from our partner producers to add to our portfolio of tried and tested decaf green coffee beans.

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Find out more about Genuine Origin on our website — https://www.genuineorigin.com/

Written by Tigger Chaturabul, copywriter for Curious Typhoon about all things coffee and beyond. Copyright Genuine Origin

We make it easy for small roasters to buy the trace-able, sustainable green coffee while empowering 50,000+ coffee producers. www.genuineorigin.com