The Coffee Lover’s Guide to Decaf Coffee

Coffee has over a thousand different compounds in it, the most well-known of which is caffeine. While many consider caffeine a desirable stimulant (and sometimes the only reason to drink coffee), a significant number of people can’t have or don’t want to have caffeine. That’s where decaffeinated coffee comes in, of course.

Here’s a look at what qualifies coffee as decaffeinated, how decaffeinated coffee is made and perhaps the most important question of all — do you really want to drink the stuff?

Is There Any Caffeine in Decaf Coffee?

The Theoretical Caffeine Content of Decaf Coffee

The description of decaf coffee as “decaffeinated” rather than “caffeine-free” is notable. Caffeine is a naturally occurring substance in coffee, and the decaffeination process seeks to remove the caffeine found in coffee from the bean. The process is largely effective, but it doesn’t make coffee caffeine-free.

In the United States, the Food and Drug Administration (FDA) requires 97 percent of a coffee’s caffeine content to be removed before the coffee can be called “decaffeinated.” The agency doesn’t require coffee companies to disclose how much caffeine is in a coffee before or after the decaffeination process, though, and that can lead to some surprising results.

Theoretically, this ratio would lead to decaffeinated coffee having a fairly negligible 2.25 to 4.2 milligrams of caffeine. The average cup of coffee ranges between 70 and 140 milligrams of caffeine, which would leave 2.25 to 4.2 milligrams left over after 97 percent removal. A few milligrams of caffeine isn’t entirely caffeine-free, but it’s not enough to have a meaningful impact on most people.

(Varietal, roast level and brew method all impact caffeine content in non-decaffeinated coffee.)

The Actual Caffeine Content of Decaf Coffee

The actual caffeine content in decaf coffee can be higher than this theoretical range, however, and it’s sometimes much higher. A couple of studies demonstrate just how much caffeine may be left in decaf coffee.

One 2006 study published in the Journal of Analytical Toxicology looked at caffeine content in decaf drip coffee and espresso shots at various businesses.

The researchers of this study first purchased 10 16-ounce cups of decaf drip coffee at restaurants and coffee shops, and all but one of those cups had caffeine in it. The caffeine content per 8 ounces ranged from 4.3 to 6.7 milligrams — just slightly higher than the theoretical range.

The researchers then purchased decaf espresso and decaf drip coffee from various Starbucks stores. The decaf espresso shots ranged from 3.0 to 15.8 milligrams per shot, and the decaf brewed coffee had between 6 and 6.7 milligrams per 8 ounces. These ranges likewise are higher than expected, although a single cup might not have too much caffeine for most drinkers.

A 2007 Consumer Reports study of decaf coffee had some more surprising findings. While the study found that most of the decafs surveyed did indeed have 5 milligrams of caffeine or less, a few outliers had a disconcerting amount of caffeine. One cup of Seattle’s Best coffee contained 29 milligrams of caffeine, and a Dunkin’ Donuts’ cup had 32 milligrams. Both of these cups were between 10 and 12 ounces, but even just 8 ounces of these coffees would have caffeine levels that were similar to many sodas.

Most Decaf Coffee Has Minimal Caffeine

In summary, decaf coffees frequently have what amounts to a negligible amount of caffeine for most coffee drinkers. Occasionally a decaf coffee will have a significant amount of caffeine, though. If you have a medical issue that even a little caffeine can affect, you should consult with a healthcare provider on whether decaf is wise to drink.

How Is Decaffeinated Coffee Made?

Caffeine is one of the larger molecules found among coffee’s 1,000-plus compounds, and the size of caffeine plays a role in how it’s removed from coffee. There are three ways that caffeine can be removed: solvent-based decaffeination, carbon dioxide decaffeination, and Swiss Water Processing.

All three of these methods follow the same basic steps:

  • The coffee beans are swollen, typically with water.
  • The caffeine is extracted from the coffee beans.
  • The swollen coffee beans are dried.

Where these three decaffeination methods differ is primarily in Step 2. They use different techniques to extract the caffeine from the coffee beans.

What Is Solvent-Based Decaffeination?

Solvent-based decaffeination is the most widespread decaffeination process, and it’s been widely used since the advent of decaf coffee. This method uses a combination of water and chemical solvents to extract caffeine during Step 2.

While water alone will extract caffeine from coffee beans, it’s unable to selectively target only caffeine molecules. Water will also extract many other molecules (which is why it’s used to brew coffee, after all).

Solvent-based decaffeination addresses this issue by infusing chemical solvents that can more selectively extract caffeine. These solvents speed up the decaffeination process, with the solvents quickly extracting caffeine before the water extracts too many other compounds.

Today, solvent-based decaffeination is primarily done with either methylene chloride or ethyl acetate. The latter of these naturally occurs in ripening fruit and is sometimes branded as “natural decaffeination” because of this. The ethyl acetate that’s used in decaffeination is synthetically produced, however. Methylene chloride is also synthetically made.

The low levels of these solvents that are used in decaffeination are considered safe, and it’s unlikely that either chemical would make it into a brewed cup of coffee even if higher levels of the chemicals were used. Coffee is roasted to around 400°F or higher, and it’s ideally brewed between 195 and 205°F. Methylene chloride and ethyl acetate both evaporate at these high temperatures.

What Is Swiss Water Processing?

Swiss Water Processing is the only organic decaffeination method, and all organic decaf coffees are made using this method. Instead of relying on chemical solvents (even if they are naturally occurring), Swiss Water Processing uses only water during the Step 2 extraction of caffeine.

To decaffeinate coffee with only water, the Swiss Water Processing method breaks the broader Step 2 down into these smaller stages:

  1. An initial batch of coffee beans is soaked in water, which extracts both caffeine and other compounds from the beans.
  2. The initial batch of beans and water are separated, and the beans are discarded while the water is preserved.
  3. The water is processed through a carbon filter, which is calibrated to remove the larger caffeine molecules but not the smaller molecules of other compounds.
  4. A second batch of beans is soaked in the same water, which mostly extracts the larger caffeine molecules because smaller compounds remain in the water.
  5. The second batch of beans is dried (broad Step 3) and roasted for brewing.

The cycle can continue with additional batches as the water can be continually recycled. Only one batch of beans must be discarded for a large run of different decaf coffees.

What Is Carbon Dioxide Decaffeination?

Carbon dioxide decaffeination is the newest method for removing caffeine from coffee. It relies on carbon dioxide gas, which itself naturally occurs in coffee beans. (Carbon dioxide will bubble up and “bloom” from freshly roasted coffee when it’s brewed.)

This decaffeination method applies carbon dioxide at pressures that exceed 1,000 pounds per square inch to remove caffeine. The carbon dioxide selectively extracts the caffeine molecules, leaving the other compounds in place.

This is an efficient and effective way to decaffeinated coffee, but it’s also an expensive one. A lot of carbon dioxide is required, and the chambers used must be able to withstand enormous pressures.

Because of the cost associated with this method, carbon dioxide decaffeination is only used for large-scale commercial decaf coffees. It’s not a financially practical way to decaffeinate small-batch or specialty coffees.

Which Decaffeination Method Should You Look for When Buying?

Many decaf specialty coffees are produced using Swiss Water Processing, as it’s an effective process that retains much of the flavor of the coffee and is truly all-natural. If you’re not worried about chemicals, other decaf coffees are worth trying too.

Does Decaf Taste Different Than Regular Coffee?

All decaf coffees do taste different from their regular counterparts, and there are a couple of reasons for this.

First, caffeine itself is a bitter white powder that acts as a natural pesticide in part because it does taste bitter. The reason people put sugar in coffee isn’t just to sweeten it up, but because the sugar molecules actively surround the caffeine molecules and block some of them from reaching the tongue. When a bitter compound like caffeine is removed, the resulting taste will change some — although the decrease in bitterness may not be enough for everyone’s liking.

Second, other subtle tastes change during the decaffeination process because it’s virtually impossible to extract only caffeine and not also remove at least a few other compounds. Coffee’s nuanced flavors come from a rich array of different compounds, and a small portion of those will inevitably be lost during decaffeination.

The extraction of other compounds will lead to a slightly duller taste in decaf coffee, as some of the compounds that give coffee its more nuanced flavors are lost. This doesn’t mean that decaf coffee is bad, however, for many decaf coffees are quite good. Additionally, there are ways to mitigate the flavor loss in roasting and brewing.

Choosing Roast and Flavor for Decaf and Caffeinated Coffee

Any flavor that’s lost in a decaf coffee will be most noticeable in light roasts and least noticeable in dark roasts. It’ll also be most noticeable in traditional brews and least noticeable in cold-brewed coffee.

A coffee’s flavor can be pictured on a continuum, where the bean’s inherent flavor and the roast’s imparted flavors are at opposite ends of the spectrum. As coffee is roasted, the inherent flavor gives way to the roasted flavor.

Since the decaffeination process doesn’t impact roast flavor, medium to dark roasts that impart more roast flavor will result in less noticeable differences between decafs and their caffeinated counterparts.

With regard to brewing, any method that uses hot water (which is most methods) will yield a more noticeable difference between decaf and caffeinated, because hot water extracts those compounds that give a coffee it’s nuanced flavors. Since decaf has fewer compounds to start with, the difference between decaf and caffeinated coffee will be accentuated by hot water.

Cold-brew coffee, in contrast, doesn’t extract the same number of compounds. Thus, it’ll help cover up decaf’s decreased number of compounds because they won’t be extracted from caffeinated coffee anyway.

While decaf can be good with any roast level and brew method, you’ll find the fewest differences between a decaf and a caffeinated coffee if the two are dark roasts and prepared as cold brew.

Does Decaf Really Deserve the Bad Reputation That It Has?

There’s no debate that decaf coffee is different from caffeinated coffee. It lacks caffeine, and there are some subtle changes in the coffee’s flavor. Those changes don’t justify an inferior reputation, though.

Decaf coffee lets many people who would otherwise be unable to have coffee enjoy the beverage, and many decafs taste quite good when roasted and brewed well. If you start with good coffee and remove the caffeine, you can still have coffee that’s quite good.