Key takeaway: Not really. Studies found caffeine barely changes during roasting, so beans start out about even. What changes is how the cup gets made. In a 2024 study with identical brewing, dark roasts generally ended up with less caffeine than light and medium roasts. Measure by weight, not by scoop, and roast becomes a flavor choice.
Ask a room full of coffee drinkers which roast has the most caffeine and you'll start a friendly fight. Team Dark says "bold flavor, bold buzz." Team Light says "roasting burns the caffeine off, so light wins."
Plot twist: both teams are mostly wrong, and the real answer is more fun. Let's settle it with actual lab data.
Does dark roast have more caffeine than light roast?
Short answer: no, not by default. Under the same brewing conditions, dark roast usually lands a little lower in caffeine, not higher.
The best recent test comes from physicists and chemists at Berry College, who brewed 30 combinations of green coffee variety, roast level and brew time in an AeroPress at a 15:1 water-to-coffee ratio, then measured caffeine with HPLC (a lab instrument that separates and counts individual compounds). Under identical brewing conditions, caffeine concentrations were generally lower for dark roasts than for light and medium roasts (Lindsey et al., Sci Rep 2024).
But here's the curveball from the same study: when they compared brews at the same extraction yield (the same share of the coffee dissolved into the cup), dark roasts generally had higher caffeine. The authors think two things compete. Roasting breaks down or drives off some soluble compounds, while it also makes beans more porous, so water gets in more easily.
Translation: the bean isn't the whole story. How you brew it decides the cup.
Does roasting burn off caffeine?
Barely. Caffeine is a tough little molecule.
A University of Glasgow team that studied roasting and extraction reported that caffeine was stable as roasting temperatures went up, while chlorogenic acids (the antioxidant-type compounds in coffee) dropped. They even suggested the caffeine-to-chlorogenic-acid ratio as a marker of how dark a coffee was roasted (Ludwig et al., Food Funct 2014).
A Czech study of 15 Arabica samples roasted light, medium and dark came to the same place: neither processing method nor roast level significantly affected caffeine content (Cwiková et al., Foods 2022).
So the "roasting burns off caffeine" idea doesn't hold up much either. Roasting reshapes flavor and aroma far more than it touches caffeine.
Why do people think dark roast is stronger?
Because it tastes stronger. Darker roasts bring more roasty, smoky, bitter notes, and our brains happily connect "bold" with "buzzy." Flavor intensity and caffeine are just two different things.
There's also a sneaky measuring effect. Roasting cooks off water and mass, and the Berry College team's microscope images showed beans getting more porous the darker they were roasted (Lindsey et al., Sci Rep 2024). Puffier beans mean a scoop of dark roast usually weighs a bit less than the same scoop of light roast. Less coffee in the filter means a little less caffeine in the mug.
Does light roast have more caffeine, then?
Sometimes, by a little, depending on how you brew. Light roasts often came out ahead of dark under identical brewing in the 2024 study above. In a Thomas Jefferson University cold brew experiment, medium roast cold brews had higher caffeine than dark roast ones too (Fuller & Rao, Sci Rep 2017).
But "light roast has way more caffeine" is the myth flipped around. The differences between roasts are usually smaller than the differences you create with your dose, ratio and cup size.
What actually changes how much caffeine is in my cup?
Way more than roast color. A 2021 review of a decade of studies looked at what drives caffeine in brewed coffee and listed coffee species, brewing time, water temperature, pressure, roast degree, grind, water type and the water-to-coffee ratio (Olechno et al., Foods 2021). The biggest per-serving amount in that review came from a brew made with Robusta beans, a species that tends to carry more caffeine than Arabica.
Real-world servings swing wildly, too. When Glasgow researchers tested 104 espressos from coffee shops in Scotland, Italy and Spain, caffeine ranged from 48 to 317 mg per serving (Ludwig et al., Food Funct 2014). Same drink name, more than a sixfold spread.
Here's your quick cheat sheet:
| What you change | Effect on caffeine in the cup |
|---|---|
| Roast level (same brew) | Small. Dark often a bit lower in one 2024 study |
| Roasting itself | Caffeine stayed stable in lab studies |
| Measuring by scoop | Dark roast scoops often hold fewer grams |
| More coffee per cup of water | More caffeine |
| Bigger mug | More caffeine |
| Bean species | Robusta tends to carry more than Arabica |
Want more on how brew method changes your cup? See Filtered vs French Press vs Espresso and Cold Brew vs Hot Coffee.
How do I control my caffeine no matter the roast?
Easy. Treat roast as a flavor choice and dose as the caffeine dial.
- Weigh your coffee. A kitchen scale takes the scoop trick out of the equation. Grams are grams, light or dark.
- Pick a ratio and stick to it. Our coffee to water ratio guide has easy numbers for every mug size.
- Watch the mug size. A 20-ounce travel mug is not "one cup."
- Know the guideline. The FDA says 400 milligrams a day for most adults is an amount not generally associated with negative effects, and that people vary in how sensitive they are (FDA). Curious how many cups that is? Read How Many Cups of Coffee a Day?
- Want less? Mix in decaf or go fully decaf. Here's our take on decaf, instant or ground.
Why does Edge roast medium?
Because medium is the sweet spot for flavor, and the science says you're not giving up caffeine to get it.
Pure Health Coffee is a Peruvian single-origin Arabica, medium roasted for notes of chocolate, caramel and roasted nuts. Dark enough for body, light enough that the bean still tastes like where it came from.
What we care about just as much is what isn't in the bag. Every lot is third-party tested by Eurofins, and our posted sample reports showed no detectable mycotoxins, including ochratoxin A below 1 ppb on our 2024 green-bean report. See them on our lab results page and learn more on our mold-free coffee page. Results apply to the samples tested.
I started Edge in St. Paul in 2020 because I wanted coffee I could verify and actually love. Keep those beans tasting great with our coffee storage guide.
FAQ
Does dark roast coffee have more caffeine? Not by default. In a 2024 study with identical brewing, dark roasts generally had lower caffeine than light and medium roasts. At the same extraction yield, though, dark roasts came out higher.
Does roasting burn off caffeine? Very little. Lab studies found caffeine stayed stable through roasting, and one study of 15 Arabica samples found roast level did not significantly affect caffeine content.
Which roast has the most caffeine? Light and medium roasts often edge out dark under the same brewing method, but the gap is usually small. Your dose, ratio and mug size matter more.
Why does dark roast taste stronger? Darker roasting creates more roasty, smoky and bitter flavors. That's flavor intensity, not extra caffeine.
Should I measure coffee by scoop or by weight? By weight. Darker beans are more porous and lighter, so a scoop of dark roast often holds fewer grams than a scoop of light roast.
Is medium roast a good middle ground? For many people, yes. It keeps origin flavors, adds body and sweetness, and studies don't show you losing meaningful caffeine to roasting.
This article is general coffee information. Caffeine sensitivity varies from person to person, so find the amount that feels right for you.
Sources
- Lindsey ZR, Williams JR, Burgess JS, Moore NT, Splichal PM. Caffeine content in filter coffee brews as a function of degree of roast and extraction yield. Sci Rep. 2024;14(1):29126. https://pubmed.ncbi.nlm.nih.gov/39582028/
- Ludwig IA, Mena P, Calani L, Cid C, Del Rio D, Lean ME, Crozier A. Variations in caffeine and chlorogenic acid contents of coffees: what are we drinking? Food Funct. 2014;5(8):1718-26. https://pubmed.ncbi.nlm.nih.gov/25014672/
- Cwiková O, Komprda T, Ĺ ottnĂková V, et al. Effects of Different Processing Methods of Coffee Arabica on Colour, Acrylamide, Caffeine, Chlorogenic Acid, and Polyphenol Content. Foods. 2022;11(20):3295. https://pubmed.ncbi.nlm.nih.gov/37431043/
- Fuller M, Rao NZ. The Effect of Time, Roasting Temperature, and Grind Size on Caffeine and Chlorogenic Acid Concentrations in Cold Brew Coffee. Sci Rep. 2017;7(1):17979. https://pubmed.ncbi.nlm.nih.gov/29269877/
- Olechno E, Puścion-Jakubik A, Zujko ME, Socha K. Influence of Various Factors on Caffeine Content in Coffee Brews. Foods. 2021;10(6):1208. https://pubmed.ncbi.nlm.nih.gov/34071879/
- U.S. Food and Drug Administration. Spilling the Beans: How Much Caffeine Is Too Much? https://www.fda.gov/consumers/consumer-updates/spilling-beans-how-much-caffeine-too-much
- Edge Coffee sample Eurofins report AR-24-JF-015481-01 (Pure Health Coffee green beans, Mar 2024), via /pages/lab-results