Decaf coffee is made by removing 97%-99.9% of the caffeine from raw coffee beans before roasting to provide a coffee beverage that reduces the potential negative health effects associated with caffeine consumption, such as anxiety, insomnia, and increased heart rate. Decaffeination of the coffee is achieved through various chemical processes, mainly classified as solvent-based or non-solvent based.
Scientifically, coffee is decaffeinated by extracting caffeine molecules. This involves soaking or steaming green coffee beans to make their cell walls permeable, soften the beans, and release caffeine. After extraction, the beans are dried, tested for residual caffeine, and analyzed to ensure flavor and quality.
Decaf coffee has been made since the early 20th century. Initially, a variety of controversial chemical solvents were used, including benzene, chloroform, and ether. However, due to safety concerns, over time, safer, less toxic, and more effective methods were developed, leading to the nine methods for decaffeination in use today, which are listed below.
- Methylene Chloride Decaf
- Ethyl Acetate Decaf
- Supercritical CO2 Decaf
- Swiss Water Process Decaf
- Mountain Water Process Decaf
- French Water Process Decaf
- Oil-based Decaf
- MIRGA Decaf
- Ethyl Lactate Decaf
1. Methylene Chloride Decaf
Methylene chloride decaf, also known as the European Method, is an FDA-approved solvent-based decaffeination process. It uses methylene chloride (Dichloromethane), a volatile, non-flammable, and colorless liquid first used in the 1970s to remove caffeine from raw coffee beans.
To make decaf roasted coffee and decaf soluble coffee extract (instant coffee) using the methylene chloride method, the U.S. Food and Drug Administration requires green coffee beans to be soaked in hot water to expand them, then washed with methylene chloride at a level not exceeding 10 parts per million (0.001 percent). This binds to the caffeine and extracts it from the beans. The caffeine-containing solution is removed, with the caffeine extracted for other uses. Nearly 100% of the methylene chloride is recovered and reused to decaffeinate more beans. The decaffeinated beans are dried and roasted at ~400°F (204°C) or higher, 2-4 times above methylene chloride's boiling point of 104°F (40°C).
The process of making decaf coffee using the methylene chloride method typically takes several hours, leaving 3-5% of the caffeine. It is a popular method, especially in Europe, due to its efficiency and cost-effectiveness. Recently, there have been calls to ban the use of methylene chloride in decaf coffee. Activist groups have petitioned the FDA and California state assembly, citing concerns about the potential health risks of even trace amounts of the chemical found in seven of 17 brands of coffee tested, according to the petition. This image illustrates the methylene chloride decaffeination process.
2. Ethyl Acetate Decaf
Ethyl acetate decaf, also known as sugarcane decaf, is an FDA-approved solvent-based decaffeination process in use since 1982. The ethyl acetate decaf method utilizes ethyl acetate, a natural, clear, colorless, and flammable ester as liquid solvent with a fruity odor and taste. This process effectively removes 97% of caffeine from coffee beans without significantly altering their flavor, aroma, or chlorogenic acid content.
Research conducted in 2009 at the Indonesian Coffee and Cocoa Research Institute and Bogor Agricultural University found that under optimal conditions (90-100°C temperature and bean size smaller than 5.5 mm), the ethyl acetate decaf method can achieve very low caffeine levels (0.3% remaining).
To make decaf coffee beans using sugarcane method, the U.S. Food and Drug Administration mandates that the ethyl acetate used must meet the specifications of the Food Chemicals Codex, 7th edition. The beans are treated with ethyl acetate in a ratio of 1:5 at a temperature of 80°F (27°C) for 8-16 hours to initially remove 37-80% of the caffeine. The extraction process is iterated until the residual caffeine concentration reaches 0.3%.
After extraction, the green coffee beans are steamed at high temperatures of 212–230°F (100-110°C), rinsed, and aerated to eliminate any residual ethyl acetate, ensuring solvent levels do not exceed 10 parts per million (ppm). Finally, the coffee beans are dried to their original moisture content before roasting. This table shows some of the decaf coffee brands that use the ethyl acetate method, as listed on checkyourdecaf.org.
| Brand | Coffee Product Name | Decaf Process |
|---|---|---|
| 1850 Coffee | Fraction Packs, Pioneer Blend Decaf, Medium Roast | Chemical solvent: ethyl acetate |
| Chock Full O' Nuts | Original Decaf | Chemical solvent: ethyl acetate |
| Chock Full O' Nuts | 1/2 Caff | Chemical solvent: ethyl acetate |
| Folgers Coffee | 100% Colombian Decaf Coffee K-Cup Pods | Chemical solvent: ethyl acetate |
| Folgers Coffee | Simply Smooth Decaf Coffee | Chemical solvent: ethyl acetate |
| Giant Food Stores | Original Coffee Decaf (Ground) | Chemical solvent: ethyl acetate |
| Giant Food Stores | Original Medium Roast Coffee Decaf (Ground) | Chemical solvent: ethyl acetate |
| Hy-Vee | Hazelnut Decaffeinated Light Roast Ground Coffee | Chemical solvent: ethyl acetate |
| Hy-Vee | Decaf Breakfast Blend Single Serve Cups | Chemical solvent: ethyl acetate |
3. Supercritical CO2 Decaf
Supercritical CO2 (carbon dioxide) decaf is a safe and non-toxic coffee decaffeination method developed by Kurt Zosel in the early 1970s. The CO2 decaf method involves treating unroasted coffee beans with supercritical carbon dioxide (CO2 in a state where it exhibits properties of both a liquid and a gas) at approximately 300 atmospheres and 150°F (65.5°C) to efficiently remove caffeine while preserving valuable coffee compounds like trigonelline and chlorogenic acid.
Carbon dioxide is a nonflammable, colorless, odorless, and tasteless gas that leaves no solvent residue and, according to researchers from the Department of Plantation Products, Spices, and Flavour Technology at the Central Food Technological Research Institute, has no known deleterious effects when used as a decaf coffee solvent. However, a 2011 study in the Journal of Food Science by food safety expert Yumin Chen indicates that melanoidins (brown pigments formed during the roasting process) may form during the supercritical CO2 decaffeination process. Furthermore, The Community Research and Development Information Service (CORDIS) suggests that while melanoidins are known to possess antioxidant properties, their effect on human health remains unknown.
Decaf coffee using the supercritical CO2 method is made by moistening green coffee beans to approximately 50% moisture content. The beans are then placed in a stainless steel extractor where liquid CO2, pressurized to 300 atmospheres and heated to 150°F (65.5°C), circulates through them, dissolving the caffeine. The caffeine-laden CO2 is then passed into a separate separator chamber, depressurized, and scrubbed with water to remove the caffeine. This process of recirculating the carbon dioxide continues for 8-12 hours until less than 0.08% caffeine remains in the decaffeinated beans.
4. Swiss Water Process Decaf
The Swiss Water Process, a coffee decaffeination method using the proprietary Swiss Water® Process, was first developed in Switzerland in 1933 by by Jean Maclang and commercialized by Coffex S.A. in 1980. The Swiss Water Process was introduced to the North American market in 1988 by The Swiss Water Decaffeinated Coffee Company of Burnaby, British Columbia.
Swiss Water Process method decaffeinates green coffee beans by soaking them in purified hot water to dissolve caffeine, sugars, and flavor compounds. The resulting flavorful, aromatic, and caffeine-rich water, known as green coffee extract, is then filtered through activated carbon to remove the caffeine. The caffeine-free, flavor-saturated green coffee extract is then reintroduced to a fresh batch of raw green beans, creating a concentration gradient that draws out more caffeine from the beans without sacrificing flavor compounds.
This process is repeated continuously for 8-10 hours until 0.1% of the caffeine remains. The decaffeinated beans are then dried to their original moisture level, ensuring that no chemical residues remain. The Swiss Water Process is made without the use of solvents, additives, or chemicals, preserving the original flavor profile of the coffee beans. This method is more expensive, resulting in a higher price for consumers, and takes longer than other decaffeination processes but is preferred by those who seek a chemical-free decaf coffee. The image below illustrates the Swiss Water Process for decaffeinating coffee.
5. Mountain Water Process Decaf
Mountain Water Process decaf is a chemical-free coffee decaffeination method that uses water from Pico de Orizaba, an active volcano and the highest mountain in Mexico. Developed by DESCAMEX, a company founded by Domingo Muguira Revuelta in 1980, and patented in 1987, the mountain water process decaf involves steaming or soaking green coffee beans in hot water to open their pores.
The beans are then soaked in mountain water, which extracts 99.9% of the caffeine while preserving the flavor oils. The caffeine-laden water is filtered to remove the caffeine and then reintroduced to the beans. Finally, the decaffeinated beans are dried to a moisture content of about 10-12% and shipped for roasting, resulting in coffee where only 0.1% of caffeine remains.
6. French Water Process Decaf
French Water Process (FWP) is a chemical-free, water-based, and flavor-preserving coffee decaffeination method introduced in New York in 1992 by Ed Wakeham, a coffee trader for Cofinco. French Water Process uses neutral pH (seven) underground water from Provence, south of France, to naturally decaffeinate coffee beans.
The process involves soaking the beans in hot water without acidity, allowing it to extract both caffeine and coffee solids. The water is then filtered through charcoal, which removes the caffeine but retains the coffee solids. This caffeine-free, flavor-rich water is then reintroduced to the beans, allowing reabsorption of the coffee solids. After drying, the beans retain a mere 0.1% caffeine, minimizing flavor loss compared to other decaffeination methods.
7. Oil-based Decaf
Oil-based decaffeination is a novel, effective, and environmentally friendly method that utilizes water-immiscible oils or fatty materials, such as sunflower, soybean, corn, peanut, and coffee oils, to extract caffeine.
A 2011 study by researchers from UAE University explored the use of sunflower oil as a less toxic alternative to traditional solvents. Their results, using a hollow-fiber membrane contactor (HFM), showed that sunflower oil alone achieved a caffeine extraction rate of 45-50%. When combined with Amberlite LA-2, a carrier that enhances extraction, the rate increased to 50-55%. The extraction process involves mixing a 20 mg/ml caffeine solution with sunflower oil (and optionally Amberlite LA-2) at temperatures between 90-120 °C.
This method not only maintains the coffee's flavor and aroma but also utilizes a non-toxic, environmentally friendly solvent, making it a promising alternative for decaffeination.
8. Decafino Decaf
Decafino is a patented technology for decaffeinating already brewed coffee and tea. The product itself is a teabag-like pouch filled with composite adsorbent beads that can remove up to 80% of caffeine in just a few minutes, all while preserving the beverage's flavor and aroma.
Each Decafino bead contains tens of thousands of pores specifically designed to target and bind caffeine molecules through a process called adsorption. This allows for the selective removal of caffeine without affecting other flavor compounds.
The beads are made from two main FDA-approved ingredients: alginate, a natural seaweed extract, and bentonite, a natural mineral. These ingredients are combined using microencapsulation, a process where bentonite particles are encapsulated within alginate material. This enhances the beads' caffeine adsorption capabilities and ensures their stability across a wide range of temperatures and pH levels.
The efficacy and safety of Decafino technology have been validated by IEH Independent Laboratory, providing assurance to consumers about the product's performance and safety.
9. MIRGA Decaf
MIRGA Decaf is a novel decaffeination method that utilizes the Mid-Infrared Generating Atomizer (MIRGA) to reduce caffeine content in coffee by 8%, while increasing theobromine by 40% and theophylline by 10-20%. Developed by Dr. T. Umakanthan and Dr. Madhu Mathi, MIRGA was patented (Indian patent application number: 201941048628) and its findings were published in 2022 in Annals of Clinical and Medical Case Reports.
To achieve these results, the MIRGA device contains a water-based solution with approximately two sextillion positively charged ions (cations) and three sextillion negatively charged ions (anions). The process involves spraying mid-infrared wavelengths (2–6 μm) onto packaged or liquid coffee and tea. This causes the ions within the solution to oscillate, generating mid-infrared energy that penetrates the packaging and acts on the coffee or tea to modify its sensory and chemical properties, enhancing both flavor and aroma.
How Was Decaf Coffee Made Historically?
Historically, decaf coffee was made using solvent methods only, with the first decaffeination process invented by Ludwig Roselius, a German coffee merchant and founder of the company Kaffee HAG, in 1903. Early health concerns about making decaf coffee focused on the potential carcinogenicity, mutagenicity, and toxicity of solvents such as benzene, chloroform, ether, alcohol, trichloroethylene, carbon tetrachloride, acetone, ammonium hydroxide, and sulfuric acid.
- Benzene: Benzene is a volatile aromatic hydrocarbon, once used in the decaffeination process, but it is now banned due to its established link to cancer, such as leukemia and multiple myeloma, as well as other serious health risks including aplastic anemia. Benzene's toxicity stems from its metabolic conversion into harmful substances like phenol, quinol, and muconic acid. A 1991 study in the British Journal of Industrial Medicine found these metabolites cause genetic damage and oxidative stress, leading to cellular and molecular harm.
- Chloroform: Chloroform, a volatile liquid initially used for decaffeination, was later banned due to significant health concerns. A 1978 study by S.G. Winslow and H.B. Gerstner, published in Drug and Chemical Toxicology, confirmed chloroform's potential to damage the liver and kidneys. This, coupled with the National Cancer Institute's findings that chloroform is carcinogenic in laboratory rodents, prompted the removal of chloroform from the decaffeination process and raised concerns about its safety in other applications.
- Ether: Ether is a highly flammable organic compound that was previously used as a solvent in the decaffeination process but has since been prohibited due to its inherent dangers and potential health hazards. A 1995 study by R.D. White, W.C. Daughtrey, and M.S. Wells, published in Toxicology Letters Journal, demonstrated that exposure to related compounds tertiary amyl methyl ether (TAME) and ethyl tertiary butyl ether (ETBE) posed significant health risks.
- Trichloroethylene: Trichloroethylene (TCE), a carcinogenic industrial solvent once used to decaffeinate coffee beans, is linked to kidney cancer, liver cancer, and non-Hodgkin lymphoma, according to a 2013 study in Environmental Health Perspectives by Weihsueh A Chiu. Due to these significant health risks, including potential harm to the central nervous system, kidneys, liver, immune system, male reproductive system, and developing fetuses, the U.S. Environmental Protection Agency (EPA) banned its use.
- Carbon tetrachloride: According to the U.S. Environmental Protection Agency, carbon tetrachloride, a toxic solvent formerly used in decaffeination, is now prohibited due to its potential to cause severe liver and kidney damage through the production of free radicals and metabolites that lead to lipid peroxidation and cellular injury.
- Acetone: Acetone is a volatile organic compound that raises concerns about its potential health effects when used in the decaffeination process. According to a study by the Agency for Toxic Substances and Disease Registry (ATSDR) published in their toxicological profile for acetone, this compound can cause neurological effects, ranging from mild neurobehavioral changes to severe narcosis, as well as hematological, renal, respiratory, ocular, and reproductive effects.
- Ammonium hydroxide: Ammonium hydroxide, while previously permitted in decaffeination, poses potential health risks upon exposure. It can cause severe irritation to the respiratory tract, skin, and eyes. Further research is needed to determine the potential for long-term damage to organs like the liver and kidneys. The Agency for Toxic Substances and Disease Registry (ATSDR) has documented the acute effects of ammonium hydroxide exposure, but additional studies may shed light on any chronic effects.
- Sulfuric acid: Sulfuric acid, a highly corrosive mineral acid identified in a 1989 study by M.O. Amdur (Environmental Health Perspectives), was once used in decaffeination but is now banned. This is due to its potential to cause severe burns, increased airway resistance in asthmatics, heightened irritant response to ozone, and impaired lung function, potentially leading to chronic bronchitis and other pulmonary effects.
Newer chemical-free methods, such as the carbon dioxide (CO2) method and the Swiss Water Process, surpass older, now-banned methods in safety, caffeine removal efficiency, and flavor preservation.
How Much Caffeine Is Removed When Making Decaf Coffee?
During the decaffeination process, the amount of caffeine removed ranges from 97% to 99.9%, depending on the method used and country regulations. The US requires a 97% reduction, the EU allows up to 3% in instant decaf, and Brazil mandates less than 0.1%. The Swiss Water Process is the most effective method, removing up to 99.9% of the caffeine and leaving less than 0.01% remaining. In contrast, oil-based decaf methods are the least effective, removing only 50-55% of the caffeine. The table below compares various decaffeination methods, outlining their processes, the percentage of caffeine removed, and the amount remaining in the final green coffee beans.
| Decaffeination Method | Description | Caffeine Removed | Caffeine Remaining |
|---|---|---|---|
| Methylene Chloride Decaf | Uses methylene chloride solvent to remove caffeine from green coffee beans. | 95-97% | 2-3 mg per cup |
| Ethyl Acetate Decaf | Utilizes ethyl acetate solvent, a natural ester, to decaffeinate coffee beans. | 97% | 0.3% remaining |
| Supercritical CO2 Decaf | Employs supercritical carbon dioxide to extract caffeine while preserving flavor compounds. | 99.0% | 1.0% remaining |
| Swiss Water Process Decaf | Uses water and activated carbon filtration to remove caffeine from green coffee beans. | 99.9% | 0.1% remaining |
| Mountain Water Process Decaf | Utilizes mountain water to extract caffeine, filtering it out and reintroducing flavor compounds. | 99.9% | 0.1% remaining |
| French Water Process Decaf | Employs neutral pH water from Provence, France, to decaffeinate coffee beans. | 99.9% | 0.1% remaining |
| Oil-based Decaf | Uses oils like sunflower or soybean oil to extract caffeine from coffee beans. | 50-55% | Not specified |
| Decafino Decaf | Uses composite adsorbent beads to remove caffeine from brewed coffee and tea. | 80% | 20% remaining |
| MIRGA Decaf | Utilizes Mid-Infrared Generating Atomizer (MIRGA) technology to reduce caffeine while increasing theobromine and theophylline. | 8% | Not specified |
Can you get addicted to decaf coffee? Decaf coffee is unlikely to cause addiction. While it contains trace amounts of caffeine (usually less than 2-15 mg per cup), this amount is too low to trigger the addiction or withdrawal symptoms associated with regular coffee. Despite the widespread consumption of decaf coffee, there have been calls to ban it due to concerns about the chemicals used in some decaffeination processes.
What Are the Reasons for Banning Decaf Coffee?
The primary reasons for the proposed ban on European Method decaf coffee are concerns over the presence of methylene chloride, a chemical used in the decaffeination process. Two activist groups, the Environmental Defense Fund (EDF) and the Clean Label Project (CLP), are calling for a ban on this method, claiming that even minute traces of methylene chloride, which can be as low as 10 parts per million (the equivalent of 10 drops of water in 10 gallons), pose health risks. However, these claims lack substantial scientific backing, as tests show that detected levels are often between 10% and 99.5% below the FDA's safety threshold. This controversy has sparked a growing interest in decaf coffee that is free of methylene chloride.
Where to Buy Decaf Coffee Without Methylene Chloride?
You can find a wide variety of decaf coffee brands that don't use methylene chloride by looking for those that use the Swiss Water Process or CO2 decaffeination. For example, at Powerbean Coffee, we offer decaf coffee without methylene chloride, made using the Swiss Water Process, roasted to order with no chemicals. Experience the rich flavor and smooth finish of our freshly roasted, chemical-free decaf coffee today.
How Does Making Decaf Coffee Affect the Taste?
Making decaf coffee can alter its taste, often resulting in increased bitterness and reduced complexity compared to regular coffee, according to a 2022 study by Danijela Šeremet from the Faculty of Food Technology and Biotechnology at the University in Zagreb. However, modern decaffeination methods have improved, allowing decaf coffee to retain much of its original flavor and aroma. Innovative techniques and blends can enhance sensory qualities, ensuring that decaf coffee remains flavorful and enjoyable.
Does Making Decaf Coffee Makes it More Acidic?
No, making coffee decaf does not necessarily make it more acidic. In fact, the acidity level of decaf coffee depends on several factors, including the type of coffee bean, roast level, brew method, and decaffeination process used. While coffee is acidic, the level can vary widely. A 2022 study published in Molecules Journal found that decaffeinated Arabica filter coffee was perceived as more bitter rather than more acidic, suggesting that bitterness, not acidity, is more affected by decaffeination.
