Not all decaf coffee is created the same

The Deets on Decaf

Food

Whether you prefer to enjoy a hot cup o' Joe or a soothing cup of chai, both coffee and tea have become enshrined in many people's daily routines. Both drinks contain caffeine, a central nervous system stimulant known to increase alertness, improve focus, and reduce fatigue (1,2). However, not everyone always wants or needs that extra caffeine kick, and too much caffeine for those that are sensitive can result in adverse health effects like migraines, anxiety, insomnia, poor sleep quality, and gastroesophageal reflux (3-8). Thankfully, that's where decaf coffee comes in! While decaf coffee may not be 100% caffeine-free, more than 97% of the initial caffeine amount in green coffee beans needs to be removed before it can be labeled as decaffeinated in the US (10). Here's a breakdown of how decaf coffee is made (hint: sometimes harmful chemicals are used), the safest and healthiest methods, as well as a list of decaf coffee brands you can try for yourself.

Why Go Decaf?

Although many of us rely on a good caffeine kick in the morning to get us going, consuming excessive amounts of caffeine can lead to deleterious health effects like increased heart rate, blood pressure, headaches, nausea, hypertension, and restlessness (1). FDA guidelines recommend limiting caffeine consumption to 400 mg a day (approximately 3-4 cups of coffee) for healthy adults, although this may vary depending on other factors like a person's caffeine sensitivity, body weight, and rate of metabolism (9). For those not looking for that extra energy boost or just trying to limit overall caffeine intake but still crave the taste of java, there is the option of choosing a decaffeinated version with lower caffeine levels. It's a common choice for an afternoon or evening cup and even for pregnant women wanting to limit their intake. But do you know how they take the caffeine out of the coffee beans? And that some processes use chemicals?

Decaf Coffee with Solvents

Stumbled upon in the early 1900s by Ludwig Roselius, the initial decaffeination process utilized benzene as a solvent, or a substance that can dissolve other substances, to remove caffeine from steamed coffee beans before they are roasted (10). When the negative health effects of benzene were discovered (and now known to be carcinogenic), more than 30 other solvents were tested for use instead (10). Today, the majority of decaf coffee created via this method use either methylene chloride (also called dichloromethane) or ethyl acetate (10,15).

Although methylene chloride and ethyl acetate are safer solvents than benzene, their use in the decaffeination process has historically caused controversy. Methylene chloride is categorized as a probable human carcinogen and a potential hormone disruptor. Ethyl acetate has less hazardous categorizations, but its use can still be very irritating to those who work with it. FDA regulations allow both to be used in the coffee decaffeination process and cite their safety in minuscule trace amounts (10,15,16,18). Both the FDA and the European Union have developed limits on maximum residue content allowed in decaffeinated roasted coffee; the US FDA maximum residue limit is 10 mg/kg (ten parts per million or 0.001%), and the EU limit is 2 mg/kg (two parts per million or 0.0002%) (10). For decaffeination plants committed to good manufacturing practices, residue content is usually between 0.3-1 mg/kg (10,14). Due to public concerns over potential health effects, there has been a rise in demand for more natural decaffeination alternatives as well as the progressive replacement of methylene chloride to 100% natural solvents (10).

The two main ways that solvents can be used to extract caffeine from green coffee beans are via direct and indirect contact, aptly named the direct method and the indirect method (10-12).

Direct Solvent Method

In the direct method, solvents are in direct contact with coffee beans to extract caffeine. Here are the steps:

  1. Green coffee beans are steamed and submerged in hot water to increase bean moisture content, open their pores, release caffeine, and be more responsive to the solvent (10,12).
  2. Green coffee beans are repeatedly rinsed with the solvent to draw out and bind caffeine away from the beans (12).
  3. Beans are steam-treated to remove solvent residues (10,17).

Indirect Solvent Method

In the indirect method, solvents are not in direct contact with coffee beans but instead share an aqueous solution. Although similar, there are slight differences:

  1. Green coffee beans are first steamed and submerged in hot water to extract all the water-soluble components, including certain flavorings and caffeine (10-12).
  2. The solution is transferred to a different tank and treated with a solvent to remove the caffeine.
  3. After caffeine extraction, the solution is reintroduced to the green coffee beans to revive their flavors (11,12).

Decaf Coffee Without the Use of Chemicals

The good news is that techniques have evolved and there are now a variety of different methods used to decaffeinate coffee that don't use any chemicals.

Swiss Water Process

The Swiss water process is unique in that it is a chemical-free decaffeination process (11). Green coffee beans are first soaked in water and the resulting caffeine-and-flavor-rich solution is strained through activated carbon, which captures the larger caffeine molecules while letting the flavor stay intact (10-14). The resulting solution, which is full of flavor and has no caffeine, has been termed Green Coffee Extract and can be used on an entirely new batch of green coffee beans to extract caffeine without losing any flavorings due to solubility and osmosis (11,14). This process can be repeated for up to ten batches with the same Green Coffee Extract before a new solution has to be created (11). Although this method doesn't use any chemicals, it may seem a bit wasteful since one batch of coffee beans is discarded for every ten batches of decaf coffee created (11). Also, some say that flavors may get mixed up among batches since the green coffee extract can carry a previous batch's flavor (11).

Carbon Dioxide Process

The carbon dioxide process also does not use any chemicals, but it does rely on supercritical carbon dioxide that is under extremely high pressure (10). Green coffee beans are initially soaked in water to increase their water content before being placed in a stainless steel container, also known as the extraction vessel (11,12). The extraction vessel is then infused with liquid CO2 at 1,000 pounds of pressure per square inch and compressed to 200 times its normal atmospheric level (11,12). The CO2 solvent dissolves and removes the caffeine from the beans while leaving behind their flavor (12). Afterward, the caffeine-rich CO2 is moved to another container so that the CO2 can be used again after turning back into a gas and naturally separating from the caffeine (12).

Give These Decaf Roasts a Shot

With so many different kinds of decaf roasts and processes used, it might seem daunting to choose one you like. However, it just takes a bit of trial and error to find what should work for you. In general, we recommend purchasing decaf coffee that was processed without the use of chemicals and to look for bags that say Swiss Water Process or CO2 Process. While the chemicals used today in the Solvent Method are not as dangerous as past solvent chemicals used, like benzene, it's always a good idea to be aware of what goes into the process (12). Down below, we've listed a few brands that use the Swiss Water Process and Carbon Dioxide Process to decaffeinate their coffees. We hope you enjoy your next cup of decaf!


References

  1. https://www.sciencedirect.com/science/article/pii/S1043276014001283?casa_token=e66HlK4F27IAAAAA:0xdKHa_jGbpmcA0EZizpIYMinE0_1hdDjHb9gDJy7iguzzv1umM6hjqr6jWVfBaMGbQcquIGmg
  2. https://www.sciencedirect.com/science/article/pii/S0278691502000960?casa_token=et2m4wMH31wAAAAA:92vq0_u6ZxqA42zrk_gBQdEaro9zoHBCQi159h5_y9mewSRYk0Pn_YdciQ_HTb6IC23_W3rwfA
  3. https://www.ncbi.nlm.nih.gov/pmc/articles/PMC7468766/
  4. https://americanmigrainefoundation.org/resource-library/caffeine-and-migraine/
  5. https://www.sleepfoundation.org/nutrition/caffeine...:~:text=Can%20Caffeine%20Cause%20Insomnia%3F,and%20overall%20poorer%20sleep%20quality.
  6. https://www.ncbi.nlm.nih.gov/pmc/articles/PMC6230475/
  7. https://pubmed.ncbi.nlm.nih.gov/7918922/
  8. https://onlinelibrary.wiley.com/doi/abs/10.1046/j.1365-2036.1997.00161.x
  9. https://www.fda.gov/consumers/consumer-updates/spi...:~:text=For%20healthy%20adults%2C%20the%20FDA,it%20(break%20it%20down).
  10. https://www.google.com/books/edition/Coffee/SRSEDwAAQBAJ?hl=en&gbpv=1
  11. https://illumin.usc.edu/where-does-my-decaf-come-from/
  12. https://www.durangocoffee.com/decaffeination-proce...:~:text=Today%2C%20there%20are%20four%20major,the%20caffeine%20from%20the%20beans.
  13. https://www.coffeeandhealth.org/all-about-coffee/decaffeination/
  14. https://www.bbc.com/future/article/20180917-how-do-you-decaffeinate-coffee
  15. https://www.livescience.com/65278-how-decaf-coffee-is-made.html
  16. https://www.ncausa.org/Decaffeinated-Coffee
  17. https://www.scientificamerican.com/article/how-is-caffeine-removed-t/
  18. https://www.accessdata.fda.gov/scripts/cdrh/cfdocs/cfcfr/cfrsearch.cfm?fr=173.255
  19. https://www.swisswater.com/pages/coffee-decaffeination-process
  20. https://www.belco.fr/green-coffee-article.php?article=473
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