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Coffee Basics

How Is Decaf Coffee Made? The 4 Methods Explained

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Jute bag with the word "decaf" stamped on the front

Although most people reaching for their morning cup of coffee are doing so in search of that desired caffeine kick, there is a percentage of the population who actually prefer decaf coffee. Not only that, but this percentage continues to steadily grow.

According to Future Market Insights, the decaf coffee market is expected to expand from $20.06 billion in 2023 to $39.10 billion in 2033.

Even with this growth in popularity, there’s still a stigma surrounding decaf and how it’s processed. Which raises the question, how is decaf coffee made?

In this article, we not only explore the different methods used to remove caffeine from coffee beans but also discuss the benefits and drawbacks of each method, as well as the pros and cons of decaf coffee in general.

How Is Decaf Coffee Made?

The process of decaffeination was first discovered in 1903 by a German coffee merchant named Ludwig Roselius. When a shipment of his coffee beans was accidentally soaked in seawater during transit, it unintentionally resulted in the extraction of the caffeine.

Recognizing an opportunity, Roselius refined the method. This process, which was later coined the Roselius Process, involved steaming coffee beans with a brine solution (salt water) and then treating them with the chemical solvent benzene to extract the caffeine.

Over time, it was discovered that benzene was carcinogenic. Understandably, this raised serious health concerns among consumers. This concern pushed the industry to innovate safer and more environmentally friendly methods. However, while coffee manufacturers no longer use benzene, in some cases, chemicals are still part of the decaffeination process.

Although the decaffeination methods used today vary in certain aspects, they all share some common characteristics:

  • The goal is to remove the caffeine while preserving the beans’ natural flavor profile.
  • The process is performed on green coffee beans that have not yet been roasted.
  • Water is an essential component in every method, often used to soften the beans or aid in the extraction process.
  • All methods involve a solvent or agent that selectively binds to or dissolves caffeine to separate it from the beans.
  • Post-decaffeination, the beans undergo a thorough cleansing to ensure the removal of any residual solvents or agents.

The four main decaffeination methods used today are the direct-solvent method, the indirect-solvent method, the Swiss Water Process, and the carbon dioxide method. 

Direct-Solvent Method

This is the oldest and most common method for decaffeinating coffee beans. To begin with, the beans are steamed for 30 minutes to open their pores. They are then rinsed for approximately 10 hours with a solvent. The caffeine is extracted from the beans during this time, binding with the solvent.

Once the solvent absorbs the caffeine, it gets drained away. The beans then undergo a second steaming to remove any remaining solvent residues. Finally, the beans are dried, roasted, and ready to be brewed.

This method commonly uses ethyl acetate (an organic compound derived from certain fruits) as the solvent. This has led to nicknames such as “The Natural Decaffeination Method” or “The Ethyl Acetate Method.”

Indirect-Solvent Method

In this method, the coffee beans are soaked in near-boiling water for several hours to extract the flavor, oils, and caffeine.

Once these elements are absorbed, the water is transferred to a different tank and treated with solvent, most commonly methylene chloride. Here, the solvent binds only with the caffeine, leaving the flavor and oils in the water.

The caffeine-laden solvent, which never comes in contact with the beans, is then skimmed from the water. Finally, the beans are reintroduced to the decaffeinated solution to reabsorb their flavors and oils.

Swiss Water Process

Swiss Water decaffeination process infographic
The Swiss Water Process is most often used by organic and specialty coffee producers that prioritize quality, taste, and chemical-free decaffeination. Filtered Grounds/Dylan Van Gerpen

The Swiss Water Process is a chemical-free method that relies on the principles of osmosis and solubility. The coffee beans are first cleaned and pre-soaked in hot water, making it easier to access the caffeine found inside.

Next, they’re introduced to a solution from an initial batch of beans that has been over-saturated with coffee compounds (Green Coffee Extract).

From there, the caffeine is drawn from the bean into the solution. This solution is then passed through activated carbon filters, which trap the caffeine molecules but allow the coffee flavors and oils to pass through.

Lastly, the decaffeinated solution is reintroduced to the beans, and the process repeats until 99.9% of the caffeine is removed.

There are other water-based decaffeination processes as well, such as the Mountain Water Process and the Natural Water Process. Although these methods use different types of filtration systems or water sources, they follow the same principles as the Swiss Water Process.

Carbon Dioxide Method

Carbon dioxide decaffeination method infographic
The carbon dioxide method is primarily used by larger commercial coffee producers due to it being well-suited for processing large batches of coffee beans. Filtered Grounds/Dylan Van Gerpen

The carbon dioxide method is the newest advancement in decaffeination.

Beans are first soaked in water and then placed in a stainless steel extraction vessel. This vessel is sealed, and liquid CO2 is introduced at a pressure of 1000 pounds per square inch. Here, CO2 is in a supercritical state (between a liquid and gas) and acts as a solvent, binding to and removing the caffeine from the beans.

Unlike other methods, the beans retain their flavor components throughout the process rather than being soaked out and put back in again. 

After the caffeine has been extracted, the CO2 is moved to a lower-pressure chamber, where it releases the caffeine and is returned to its gaseous state. The CO2 can then be reused for the next batch of beans. What’s left behind are now caffeine-free beans that, once dried, are ready for roasting.

Which Decaffeination Method Is Best?

The question of which decaffeination method is best continues to be a topic of debate for both consumers and producers.

Although benzene and other harmful chemicals have been phased out, modern techniques, such as the direct and indirect solvent methods, still use chemicals in the decaffeination process. Despite the FDA’s assurances that these chemicals are safe at their current usage levels, many health-conscious consumers remain wary. 

When comparing the two non-chemical-based methods, neither is universally superior. For instance, the Swiss Water Process has garnered significant attention because it’s the sole method employing only water to remove the caffeine from the bean.

However, the Carbon Dioxide Method utilizes the same natural gas plants require to live and grow. Although its adoption in the specialty coffee segment remains limited due to how expensive it is to perform, it’s often heralded as the future of decaffeination.

While the Carbon Dioxide Method’s natural appeal might resonate with some, others might be drawn to the chemical-free purity of the Swiss Water Process or the tested reliability of solvent-based methods.

Ultimately, which decaffeination method is the best comes down to your priorities and weighing factors like health concerns, environmental considerations, and economic realities. 

Does Decaf Coffee Still Have Caffeine?

While decaf is a popular choice for those looking to enjoy the rich flavor of coffee without the stimulating effects of caffeine, does decaf actually mean caffeine-free? The short answer is no. 

Depending on the method used, the decaffeination process removes roughly 97% or more of the caffeine in coffee beans. As a result, a typical 8-ounce cup of decaf coffee will still contain a small amount of caffeine, typically ranging from 2-5 mg.

In comparison, an 8-ounce cup of regular brewed coffee can pack anywhere between 70-140 mg of caffeine, making the amount of caffeine in a cup of decaf significantly lower but not absent.

Although the amount of caffeine in decaf might seem negligible, it’s essential to be informed, especially if caffeine plays a critical role in specific areas of your health.

For individuals with certain medical conditions, those taking medications known to have adverse reactions when combined with caffeine, or those particularly sensitive to caffeine, even modest amounts can have unintended consequences. 

While decaf coffee is a far cry from its regular counterpart in terms of caffeine content, it’s not entirely caffeine-free. If you have questions or concerns about your caffeine consumption, it’s best to consult with a healthcare professional.

What Are the Pros & Cons of Decaf Coffee?

As with most things in life, there are both advantages and disadvantages. Decaf coffee is no different. Here is a breakdown of some of the pros and cons to consider when opting for decaf:

Pros:

  • Less caffeine: The most apparent benefit is decaf offers a way to still enjoy the taste of coffee while limiting your caffeine intake.
  • Fewer side effects: There is such a thing as too much caffeine. Since decaf has significantly less caffeine than regular coffee, it can help you avoid the common side effects associated with caffeine overconsumption, such as headaches, increased heart rate, and insomnia.
  • Health benefits: Decaf coffee still offers many of the same benefits as regular coffee, such as antioxidants and biologically active compounds that promote heart health, increase longevity, and reduce the risk of some cancers.

Cons:

  • Caffeine content: While decaf coffee has significantly less caffeine, it still contains a small amount. This can still be problematic for individuals with certain health conditions or caffeine sensitivities.
  • Decaffeination method: It can be challenging to determine the decaffeination method used for your cup of coffee, as there aren’t specific labeling rules requiring disclosure of this information on the packaging. As a rule of thumb, where there isn’t information about the decaffeination method, it usually means a chemical solvent was used.
  • Taste difference: Some coffee enthusiasts argue that decaf lacks the depth and richness of regular coffee. This could be partly due to some of the natural compounds being unintentionally removed during the decaffeination process and the fact that decaf coffee beans are notoriously more difficult to roast.

Ultimately, whether you choose to pour yourself a cup of decaf comes down to personal preference. While decaf coffee has its advantages, such as reduced caffeine content and some fantastic health benefits, there are also drawbacks to consider, including the decaffeination process and potentially sacrificing taste.

Final Thoughts

The decaffeination process has evolved significantly over the years, with improvements focused on the consumer’s health and ensuring that decaf coffee beans retain their natural flavor profiles. Whether you choose a cup of decaf over its caffeinated counterpart is ultimately a matter of personal preference.

If you’d like to delve deeper into the vast world of coffee to help you make that decision, our coffee basics section is a great place to start. And if you’re interested in improving your home brewing techniques, check out our brewing guides.

Frequently Asked Questions

Caffeine’s effects can vary depending on factors such as body weight, metabolism, and sensitivity. When consumed in moderation, caffeine can offer numerous benefits, such as improved mental alertness, enhanced physical performance, and a reduced risk of certain diseases. However, it can also lead to sleep disturbances, dependency, increased heart rate, and digestive issues, especially when consumed in high amounts.

Yes, decaf coffee can taste different from regular coffee. The decaffeination process can strip away not only the caffeine but also some of the natural oils and flavor compounds present in the coffee beans. While decaffeination methods have improved in retaining flavor, subtle differences in taste, aroma, and body can still arise.

Decaf coffee is generally more expensive to produce than regular coffee due to the specialized decaffeination processes involved. These methods lead to weight loss in the beans and can require additional waste disposal. Furthermore, certain specialty or niche markets can involve additional certifications, branding, or quality checks. As a result, these added costs can make decaf coffee pricier at the retail level.

Yes. While it is possible to overdose at extremely high levels, the general guideline for caffeine consumption in healthy adults is much lower. It’s recommended to limit caffeine to a maximum of 400 mg per day. Pregnant and nursing women, as well as individuals with health conditions, should follow even more conservative guidelines. As for kids, while there aren’t any official U.S. guidelines, it’s strongly advised that children under 12 years of age avoid consuming caffeine, while teens should limit intake to less than 100 mg per day.

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AUTHOR

Hey there! I'm Michael, founder and editor-in-chief of Filtered Grounds. In addition to being an entrepreneur, I'm also a bit of an endurance sports junkie. Whether it's working toward my business goals or training for my next Half Ironman triathlon, a good cold brew or cup of French press plays a role in fueling my performance.