Does Dark Roast Have More Caffeine? Debunking the Myth

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does dark roast have more caffeine

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Don’t feel bad for asking. I’m just as guilty, or I was. It’s reasonable to look at a hopper full of dark roast beans and assume there will be more caffeine than a lighter roast offers.

Unfortunately, it’s more complicated than that. I’ll give you the fast and loose answer for those in a hurry, but I’m begging you, take the time to finish reading. There is a correct answer to this, but it’s more than a quick blurb can cover.

A dark roast coffee bean has roughly the same caffeine content as a light roast. However, this changes when and how you measure your roasted coffee for brewing.

What’s in A Roast: Dark vs. Light Roast Coffee

what's in a roast dark vs light
Let’s review some of the basics about dark and light roasted beans.

I hope you’re still with me because I basically gave you the long answer equivalent of it depends. And I’m not exaggerating when I say it’s the absolute worst answer to any question. I hate it.

So let’s get you a better one!

Before someone yells at me, declaring me a liar, let me clarify something. Light and dark roasts from the source share about the same amount of caffeine, but this only applies to identical bean types. 

Comparing an arabica bean with the caffeine content of a robusta bean will show variations. In fact, studies have shown that robusta coffee beans contain considerably more caffeine than arabica.

robusta beans have a lot more caffeine than arabica
Just an FYI, different types of beans vary in caffeine content.

What you should know about roasting coffee beans is that the roasting doesn’t affect caffeine content. The flavor, color, and density are what change through the heating process.

A richer taste in coffee is the goal with darker roasts. And while the majority of its moisture is expelled during heating, the caffeine remains.

What’s left is a coffee bean that’s grown in size but trimmed of excess weight.

Dark Roast Caffeine Content

That fuller taste means dark roast has more caffeine, right? Sorry, it’s still not that simple. Didn’t I say caffeine levels are essentially the same in light and dark roasts? You bet I did.

The discrepancy occurs when you start prepping your brew. Or when the manufacturer packages the beans for sale. And depending on how this process happens, it will affect the dark roast caffeine content.

how are you prepping your coffee beans scoop or scale
Pre-planning how you want to brew your coffee will help you decide on your roast.

Yes! You can have more than one outcome.

Dark Roast Caffeine Content vs. Light Roast: By Volume

When comparing caffeine content by volume, light roast coffee has more caffeine than dark roast.

When measuring coffee with volume, by scoop or bag, your dark roast, which is much lighter, will have less caffeine per volume. Think of it like this… 

Imagine two piles of beans, one light and one dark. The amount of caffeine that rests inside each is precisely the same. But because it was roasted longer, the outer shell of the darker bean is double in size.

So when you package both sets of beans, you will fit a lot more light roast into the bag than you would dark roast, thanks to the size ratio of bean to bag.

more caffeine in light roast by volume
Brewing by volume will most certainly make light roast your better caffeine fix.

Make sense?

Dark Roast Caffeine Content vs. Light Roast: By Weight

If measuring coffee by its weight, using a proper scale, the dark roast would offer more caffeine than a light roast would.

Using the same analogy as before, imagine you wanted to weigh out the coffee beans to get the exact same weight. Let’s say we wanted 12 ounces of coffee.

Because the light roast beans are heavy, it may only take 2000 beans to get to 12 ounces if each bean weighs .17 grams. But with a lighter, darker roast, it’ll take 833 more beans to get the same 12 ounces of coffee, based on an average of .12 grams per bean.

more caffeine in dark roast by scale
Measuring with a scale shifts the balance of caffeine prominence to dark roast.

I’m not the best at math. But if the caffeine is the same for each bean, and one bag gets over 800 more beans than the other, that’s more caffeine! And we need a bigger bag.

Does Medium Roast Coffee Have More Caffeine than Dark Roast?

A medium roast coffee is lighter than a dark roast, thus heated for less time. So, like the comparison of dark vs. light, its caffeine content is the same until you begin the brewing/packing.

When measuring by volume, the medium roast will have more caffeine than the dark roast. And when measuring by weight, greater levels of caffeine will be found in the dark roast.

I know this can be a little complicated when first running through it. If it helps, take a look at this video by James Hoffman. He does an incredible job testing the caffeine levels of different roasts and brew methods. 

Dark Roast Caffeine Content and Its Effects on Flavor

Before you take your answers and go, let me talk about another aspect of dark roast coffee and its misconceptions.

First off, more caffeine doesn’t equate to better taste. Many people assume that a more robust cup of coffee is related to caffeine, but the truth is the roasting process amplifies the coffee bean’s natural properties.

It’s a real-life chemical and physical transformation at high temperatures.

Is Dark Roast Coffee the Strongest?

It really comes down to what you consider strong. Is it that extra kick that even the first scent clues you in on, or is a sweeter taste more fitting for you?

Whatever your preferences are, dark roast coffee is generally considered the strongest brew. 

dark roast is the strongest brew
Generally, a dark roast is accepted as a strong cup of joe.

Roasting coffee creates a change in the bean that intensifies the flavor. One contributing factor is the Maillard reaction, a chemical exchange between sugars and amino acids during high temperatures that induce distinct tastes.

And considering that dark roast coffee is exposed to hotter environments, it makes sense that they’d offer the most robust cup.

Is Dark Roast Coffee More Bitter?

Yes, dark roast coffee is more bitter than others. The longer the coffee beans roast, the longer they are exposed to chemical transformations meant to extract the caffeine while diminishing the natural sugars and amino acids.

Caffeine is bitter in its natural state, and that’s not necessarily a bad thing! But if it’s too bitter for your liking, it means you over extracted what should have been a balanced brew.

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