How Much Caffeine is in Decaf Coffee?
Decaf coffee gets a bad rap in the coffee world for ‘ruining’ the taste of coffee beans. However, whether for health reason or because of sensitivities to caffeine, at some point many of us have to switch to decaf in order to continue our love for coffee without experiencing the side effects of caffeine.
Theoretically, companies selling decaffeinated coffee must meet government-regulated standards before they can label their product “decaf.” Those standards are 97% free of caffeine for the United States and 99.9% free for the European Union.
That’s why it may surprise you to learn that decaffeinated coffee is not actually 100% free of caffeine in practice. One recent study published by the Journal of Analytical Toxicology found that samples of decaf coffee from a random selection of restaurants and coffee shops contained anywhere from 8.6 milligrams to 13.9 milligrams of caffeine. This is nowhere near what a regular coffee drinker might consume in one day (there is somewhere between 95 and 165 milligrams of caffeine in a regular 8 oz cup of coffee), but it is clear that “decaffeinated” does not translate to “caffeine-free.”
So how much caffeine is really left in your cup of decaffeinated coffee? Without being a coffee chemist, you can roughly guess whether your decaf falls on the high or low end of the spectrum by understanding the factors that affect caffeine: decaffeination method, brewing method, coffee bean species, etc.
Here’s a breakdown of what we know about how caffeine ends up in our decaf coffee.
History of Decaf Coffee
The first attempts to decaffeinate coffee date back to the early 1800s. In 1820, Friedrich Ferdinand Runge isolated caffeine as the culprit that made coffee drinkers experience insomnia. His first attempts to extract the caffeine from coffee beans involved adding chemical solvents directly to roasted beans. It worked in removing the caffeine, but the flavor of the beans was also so adversely affected that the resulting coffee was undrinkable. His next idea was to grind the green coffee beans and extract caffeine that way, but then it was too difficult to roast pre-ground beans.
It was a man named Ludwig Roselius who first developed a commercially successful way to decaffeinate coffee in 1906. Roselius found that he could make green coffee beans porous by steaming them, at which point he applied a chemical called benzene to extract caffeine. It worked, and we still use this basic process in some decaffeination methods today, though we no longer use benzene as it was later found to be a carcinogen.
One of the factors that affects how much caffeine is in your decaf coffee beans is how coffee companies decaffeinated their beans. We have come a long way from the earliest attempts at decaffeination, and today there are four main methods of decaffeinating coffee beans, and two of them are essentially the same concept but use a slightly different process.
Coffee is decaffeinated in its raw, green bean form before it is roasted so as to preserve flavor, aroma, and texture. Here is an overview of the different ways that coffee manufacturers decaffeinate green coffee beans.
Solvent methods use chemicals to extract caffeine from coffee beans, similar to the original attempts at decaffeination. This is still the most common process of decaffeination and has improved over the years so that there is rarely such a strong, lingering chemical aftertaste with decaf beans today. There are two different types of solvent methods: direct, where chemicals are applied directly to the beans, and indirect, where chemicals are applied to coffee-soaked water. The two most common chemicals used for the decaffeination process are methylene chloride and ethyl acetate.
First, beans are soaked in water and then flushed with methylene chloride, which is the most commonly used chemical in this process to draw caffeine from raw, green coffee beans. Those beans are then flushed to rinse away the chemical before roasting (see here).
In this method, green coffee beans are first soaked in hot water and then removed at which point the coffee-flavored water is treated with ethyl acetate to remove the caffeine. The next step is a separate process of adding the flavored, decaffeinated water back to the coffee beans before they are dried. The final step is a rinse of the beans to ensure that traces of leftover ethyl acetate are washed away.
There are two methods of decaffeination that do not involve chemicals at all. Both of these processes are relatively new, and are favored by specialty coffee brands:
Carbon Dioxide Process
The newest way of decaffeinating coffee, the carbon dioxide process relies on placing water-soaked coffee beans in a sealed, stainless steel container and blasting them with liquid CO2 at 1,000 pounds per square inch to pressurize caffeine out of the beans. The CO2 flows into another chamber where it is then depressurized and returns to its normal gaseous state. The carbon-dioxide method is fairly expensive, so it is more often used by commercial-grade brands who can afford it. Check out this video here to see a visualization of this process.
Swiss Water Process
This is the only method available that is guaranteed to be organic, as the Swiss Water Process is patented and the plant is certified Organic by both OCIA and Aurora Certified Organic, in addition to being certified Kosher by the Kosher Overseers Association. It’s the most popular method with specialty coffee roasters because it is completely chemical free and reduces 99.9% of the caffeine from green coffee beans. Beans are soaked in water and then the company adds something called Green Coffee Extract (GCE) that relies on the science of equilibrium to draw the caffeine out of the beans and into the GCE. The GCE is then reusable and the whole process is eco-friendly and sustainable.
To hear a better explanation of the Swiss Water Process from the company itself, listen to this video here.
For an interesting view of the mechanical process behind this decaffeination method, check this video out (see here).
Arabica vs. Robusta
Now that you know which methods to look out for, the next step is to know which coffee beans you are buying. There is a wide variety of coffee species in the world, but only about two commonly make their way into your coffee cup. You may have even seen the words “100% Arabica beans” on the side of your specialty coffee beans bag. Robusta accounts for about 25% of coffee bean production and the other 75% is Arabica.
There are some differences between taste, ease of farming, and quality, but the biggest factor to remember for today is that Robusta beans have about twice as much caffeine as Arabica beans, which can account for their slightly more bitter taste. Arabica beans are about 1.5% caffeine and Robusta have about 2.7% caffeine.
Check the labels on your beans or call the manufacturer to make sure that you are buying 100% Arabica to minimize the caffeine content of your decaf beans. Most instant coffees are made from Robusta, and many espresso mixes, especially those of Italian origin, contain at least a portion of Robusta. Most specialty coffee brands use Arabica beans, but it is always a good idea to check.
Roast Affects Caffeine Content
Contrary to some common myths and misunderstandings, there is actually not much of a difference in caffeine content between light and dark roast beans. Many people believe that lighter roasts are higher in caffeine than dark roast beans because the roasting process burns off caffeine. That’s actually not true!
However, the roasting process does change the mass of coffee beans and causes them to lose water. So beans that have been roasted longer —dark roasts— have less mass than light roast coffee beans. This means that if you were to weigh 10 grams of light roast beans and 10 grams of dark roast beans, you’d have just a few more dark roast beans than light ones.
So depending on how you measure your coffee for brewing, your roast matters. If you measure your coffee by scoops (volume) then light roasts will result in more caffeine because they have more density. If you are measuring by weight, then dark roast beans will result in more caffeine content since they have less mass.
If you don’t have much of a preference between light and dark roasts and are trying to decrease your caffeine intake, it may be a good idea to think about how you measure and brew coffee and buy your beans accordingly.
Using Brewing to Affect Caffeine Levels
The study that we mentioned earlier where researchers actually tested random samples of decaf coffees from restaurants and shops yielded some other interesting results: a sample of espressos and regular drip coffee from the same Starbucks had different caffeine contents (see here). This could have been an error of testing or any number of variable factors in caffeine content, or it could be the result of a difference in brewing process resulting in different caffeine levels.
Brewing method affects how much caffeine ends up in the final cup of coffee, so it is entirely possible that the difference in caffeine between Starbucks drinks went back to how the coffee was prepared.
The longer that coffee is brewed, the more time caffeine has to be extracted from the grounds and into the final liquid. So, for example, the very short brewing period for an espresso results in a lower caffeine content than the long brewing period for a french press.
In addition, hotter water extracts more caffeine than cold water. So while cold brew has an extraordinarily long brewing time (up to 12 hours depending on how strong of a brew you like), the cold water usually results in coffee with a considerably lower caffeine content.
The bottom line is that caffeine content is highly variable. Even if you tweak your brewing, buy the right beans, and adjust the brewing temperature, there are a number of factors that may influence the final product and there is no guarantee that your experiment will work. However, if you are serious about learning how caffeine ends up in your decaf coffee, these are some helpful markers to understand.
Is Decaf Safe?
So is decaf coffee a viable option for people avoiding caffeine for health purposes or because of caffeine sensitivities? The answer is ‘probably’, but in moderation.
First, be mindful of which decaf coffee you are consuming. As we learned above, decaffeination processes are not created equally and some leave more caffeine in the beans than others.
The Swiss Water Process removes about 99% of the caffeine from beans because they soak in water for so long. However, some people find that this soaking process destroys much of the coffee’s taste so you may prefer using coffee beans decaffeinated with the carbon dioxide method. We recommend you try them both to decide which flavor you prefer.
While you can minimize the caffeine content in decaf by choosing the right decaffeination process, Arabica or Robusta beans, and brewing method, the ultimate answer to whether you are still able to drink decaf without caffeine side effects comes down to individual sensitivities. If you choose a Swiss Water Process decaf Arabica bean brewed as a pour over and still feel jittery or anxious, you might be ultra-sensitive to caffeine.
If you are pregnant or nursing, it might be safest to avoid coffee altogether so as not to risk the adverse side effects of coffee. Always discuss these issues with your doctor or healthcare provider.
Decaf Coffee and Taste
Decaf has a bad reputation among coffee lovers for having a metallic, chemical-like taste. Much of this poor reputation is due to the way that coffee was historically decaffeinated using solvent methods and heavy chemicals that left their mark on the taste of the beans.
As decaffeination methods have improved over the years, so has the taste of decaffeinated coffee. Many people still find decaf to lack the flavor and aroma of regular coffee, but there are a few brands on the market from reputable coffee companies that have rave reviews and whose dedicated consumer base swears there is no difference in taste. We’ve compiled a list of those that you can view here.
Final Word of Advice
If you need to switch to decaf for health or medical reasons and are worried about taste, our best advice is to try different brands to find something that you like. We also might suggest ordering something like an espresso drink, perhaps a decaf double shot cappuccino. The milk in a cappuccino provides a rounder, softer taste to the espresso and may mask any unfortunate flavors of the decaf beans while still giving you a dose of strong coffee.