Is There Caffeine in Decaf Coffee?

Decaffeinated coffee, or “decaf,” is often assumed to be caffeine-free. In reality, decaf coffee is not 100% free of caffeine but it comes pretty close. This article will dive into exactly how much caffeine remains in decaf coffee, how it compares to other drinks and foods, and how we measure it. Grab a (decaf) cup and let’s demystify what’s in it!

How Much Caffeine Is in Decaf Coffee?

Decaf coffee does have a little caffeine, but far less than a cup of full caff. On average, a cup of decaf coffee (about 8 ounces or 240 ml) contains only around 2–7 milligrams of caffeine. This is only a fraction (roughly 2–5%) of the caffeine in a typical cup of regular coffee — of course, the exact amount depends on the way it was prepared and the dosage used.

In percentage terms, decaffeination removes approximately 97% of the caffeine from coffee beans. For example, research has found that a standard 240ml cup of brewed coffee has about 95 mg of caffeine, whereas an equivalent cup of decaf might have only about 4 mg.

One scientific analysis of decaf from various coffee shops found a range of 0 to 13.9 mg of caffeine in a 16-ounce (475 mL) serving of decaf coffee. Even a decaf espresso shot from Starbucks was found to contain between about 3.0 and 15.8 mg per shot in the same study.

To put these numbers in perspective, here’s how decaf compares to some common beverages and foods containing caffeine:

• Decaf coffee (8 oz/240 mL): ~2–5 mg caffeine
• Regular coffee (8 oz/240 mL): ~95 mg caffeine
• Black tea (8 oz/240 mL): ~40–50 mg caffeine
• Green tea (8 oz/240 mL): ~25–30 mg caffeine
• Cola soft drink (12 oz/355 mL can): ~40 mg caffeine
• Dark chocolate (1 oz/28 g): ~20–25 mg caffeine (milk chocolate of the same size has around 5–6 mg)

As you can see, decaf coffee’s caffeine content is low. In fact, you would likely have to drink 10–20 cups of decaf to equal the caffeine in one cup of normal coffee! However, if someone is sensitive to caffeine they need to be aware of this as a cup too many might affect them.

How Do Regulations Define “Decaf” (US vs EU)?

Since decaf coffee isn’t completely caffeine-free, how is it defined legally? Well, there’s not a single answer. Different countries have set standards to ensure decaf really is almost caffeine-free. This means that it’s theoretically possible for the same coffee to be decaf in the US and low caff in the UK, for example. I’ve only come across this once, with the Los Nogales decaf/low-caf. The current regulations are discussed below:

• United States: In the U.S., federal guidelines (FDA) don’t permit a specific milligram amount on labels for decaf, but the industry follows a standard that at least 97% of the caffeine must be removed from the coffee beans in order to call it decaffeinated. In practice, that means a decaf coffee bean will have only around 2–3% of its original caffeine content left. For example, if a batch of beans started with 1.2% caffeine by weight (typical for Arabica beans), after decaffeination it would have around 0.04% caffeine remaining. This translates to just a few milligrams per cup when brewed. The FDA has reviewed common decaffeination processes and found no safety concerns with them, and decaf coffee products that meet the 97% caffeine reduction benchmark are considered true “decaf."
• European Union: The EU’s regulation is even more explicit: decaffeinated coffee must contain no more than 0.1% caffeine on a dry weight basis for roasted coffee beans (and no more than 0.3% for decaf instant coffee). In other words, 99.9% of the caffeine must be taken out of decaf coffee in the EU. For consumers, this ensures that any product sold as “decaf coffee” in Europe truly only has trace amounts of caffeine.

In practical terms, whether you buy decaf in New York or in London, you can expect that a cup will have only a few milligrams of caffeine at most, having around 97–99% of caffeine removed from the product.

How Is Caffeine Content Measured in Decaf Coffee?

You might wonder, how do we know these numbers – who’s measuring 4 mg of caffeine in a cup, and how? The caffeine content in coffee (including decaf) is typically measured by scientists using laboratory analytical techniques. Unfortunately, it’s not something we can measure at home or at the roastery, unless you are James Hoffman.

One of the most common methods is High-Performance Liquid Chromatography (HPLC), which refers to a process that separates the components in a liquid and allows precise measurement of specific substances. In plain terms, to measure caffeine in decaf coffee, a sample of the coffee is taken (either liquid brew or a portion of the beans/grounds) and run through an HPLC machine. The machine basically separates out the caffeine from everything else and quantifies it. This is how researchers determined, for example, that a decaf sample had 7 mg vs 3 mg of caffeine; the HPLC chromatogram will show a caffeine peak that can be measured against a standard (you can see how HPLC works here).

Some labs use other techniques like gas chromatography paired with mass spectrometry or UV-Visible Spectrophotometry. Maybe something we can discuss in a future article!

And The Answer Is…

Yes, decaf coffee does contain a little caffeine but only a small amount (a few milligrams per cup, or about 97% less than regular coffee). For most people, this residual caffeine is too low to matter in any practical sense but people with health issues and extreme sensitivities should be aware of it.