CoffeeFilter: Does light roast have more caffeine than dark?

February 6, 2007 11:11 AM

CoffeeFilter: Does light roast coffee really have more caffeine than dark roast?

I heard this from a barista at a Caribou Coffee the other day, and I've Googled it extensively. I've found sites that say there's almost no difference at all, and sites that seem to indicate that the difference is noticeable. I just don't know whom to believe.

Does anyone know of a study of this question that's been done with actual, scientifically obtained data to back up a conclusion, one way or the other? I want to know how to get the most caffeine bang for my buck.

posted by cerebus19 to food & drink (17 answers total)

This article in J. Agr. Food Chem. looks like it would have the data, but I can only access the abstract myself.
posted by exogenous at 11:17 AM on February 6, 2007

I can't cite any studies, but I did see a documentary about the history of coffee the other day that mentioned this idea. The documentary stated that lighter roasts do indeed have more caffine than darker roasts due to the fact that the roasting process destroys caffine. Therefore, the longer the roast the less caffine.
posted by ISeemToBeAVerb at 11:29 AM on February 6, 2007

Here's my completely non-scientific anecdotal answer:

When I roast beans, if I inhale the smoke that's coming off them, it gives me a caffeine buzz. That would indicate to me that at least a little bit of caffeine is being burned off the longer the beans cook. I'm sorry I don't have any hard data for you, though.
posted by Addlepated at 11:30 AM on February 6, 2007

I got my barista training via Seattle's Best, and we were taught that lighter roasts do have more caffeine, but it was a very slight difference. Try an Americano some time - it's hot water and espresso, and tastes similar to coffee. Depending on whose statistics you believe, and what size you get, it may have more caffeine than a similarly sized coffee.
posted by booksherpa at 11:58 AM on February 6, 2007

Here's the info from that journal article

caffeine (mg/mL)

Arabica (n = 6) ± SD 2.09 ± 0.10a


Robusta Natural blend (n = 6) ± SD 2.88 ± 0.14b


Robusta Torrefacto blend (n = 6) ± SD2.96 ± 0.10b

Note that they classified Robusta as mostly dark, and Hazelnut and Arabica as lighter roasts.

So it seems, at least from this study, that darker = more caffeine.
posted by jourman2 at 12:34 PM on February 6, 2007

* I meant to write that Robusta Natural is classified as lighter (not Hazelnut - they didn't test any called Hazelnut).
posted by jourman2 at 12:36 PM on February 6, 2007

I'm so glad you asked this. The other day my friend's dad tried to tell me that there is no caffeine in espresso. I bit my tongue because he really wanted to be right but I've been thinking about it ever since.
posted by wallaby at 12:48 PM on February 6, 2007

jourman2: Robusta has much more caffeine than arabica, which would, I think, swamp any differences caused by a light or dark roast.
posted by markr at 1:25 PM on February 6, 2007

Robusta beans would give the most caffeine bang for the buck, as they are cheaper than arabica and have about twice the caffeine. But anything you get at a good coffee house will likely be 100% arabica.
posted by peeedro at 1:55 PM on February 6, 2007

I believe that in an episode of Good Eats Alton Brown said that lighter roasts retain more of their caffeine.
posted by Rhomboid at 3:44 PM on February 6, 2007

Caffeine definitely comes out in the roasting process- I used to date a coffee roaster, and if I hung out with him while he roasted, I'd be jittery for hours afterward. That being said, I don't know if you'd notice the difference in caffeine between a light and dark roast. A lot of the caffeine comes out with the the steam at the beginning of the cycle, and I'm not sure if that continues in any significant during the carmelisation process. The theory makes sense, but I'm not sure if it has real world applicability.
posted by oneirodynia at 4:46 PM on February 6, 2007

"... any significant way".
posted by oneirodynia at 4:47 PM on February 6, 2007

Thanks for the info. I should've mentioned, I suppose, that I'm aware that Robusta beans are higher in caffeine than Arabica, but of course they also taste much worse. I want the most bang for my buck without compromising taste.

It sounds like there's not much difference, but there is a little more caffeine in light roast.
posted by cerebus19 at 5:53 PM on February 6, 2007

IAAB and I've been trained that yes, caffeine does come off the beans during the roast process making a light roast contain slightly more caffeine than a dark roast.

Incidentally, an 8oz cup of coffee also contains more caffeine than a 1.5oz shot of espresso, so if you really want to wake up, skip the small latte and just have a regular cup of Joe*. We use a medium roast coffee for our espresso because a dark would just be too damned strong. Some places use a vienna-style espresso where the beans are actually a light roast, so this may vary from cafe to cafe.

*(Unless of course you want three or four shots of espresso in said latte and then, well, I'll be peeling you off the ceiling later on.)
posted by grapefruitmoon at 8:14 PM on February 6, 2007

cerebus19: Not to be a corporate shill, but if you want the most bang for your buck, Seattle's Best Organic Sumatra is a light roast that is also totally delicious and gives the earth a hug.

And if you buy a bag on Fridays, you get a free drink.

And yes, we totally grind that.

I'm done now.
posted by grapefruitmoon at 8:16 PM on February 6, 2007

Seconding filter coffee having mroe caffiene than expresso. Expresso pushes steam through the beans really fast, so less caffiene has time to dissolve and come out, whereas plunger or filter coffee steep the beans in water, maximising the caffiene release. I don't have the journal article on hand but I recall it being something like one third the caffiene in a shot of expresso that you get in a standard cup of coffee. This is likely to be a much greater difference than you'd see with the light vs dark roasting thing.
posted by shelleycat at 9:35 PM on February 6, 2007

grapefruitmoon: I like Seattle's Best, but I'm in Northern Virginia, where the only place to find Seattle's Best is at a Borders bookstore. If I go to a coffee shop, I typically get a latte or mocha with three shots of espresso.

Yes, I like caffeine. If I'm feeling especially tired, I'll have what many places call a 'red eye," which as you probably know (but others might not) is a cup of regular coffee with a shot or two of espresso added to it. Instant caffeine buzz.
posted by cerebus19 at 6:57 AM on February 7, 2007