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Caffeine in Coffee


B.A.R.

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I then decided to order dessert, and had my eye on the chocolate cake which is mentioned on the Web site (and a few posts upthread) , only to be told "we don't have that anymore". Being a chocaholic, I was crestfallen. I opted for the pecan pie and a decaf coffee, until I was told "we don't have decaf". Hmmm. Well, then, how about regular coffee? "We don't have that, either. How about espresso?" All right, then, I'll just pull an unexpected all-nighter.
Reading this made me wonder about this. I was under the impression that although espresso TASTES stronger, it actually has much less caffeine, per volume, than brewed Arabica bean coffee.

How I feel after drinking each certainly supports this notion. Any actual facts to back this up?

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Espresso generally has less caffeine than coffee because the water does not spend as much time in contact with the grounds to leech it out, and you drink a lesser volume of espresso than coffee. Of course, this varies depending on the volumes of coffee and espresso you are talking about.

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Reading this made me wonder about this. I was under the impression that although espresso TASTES stronger, it actually has much less caffeine, per volume, than brewed Arabica bean coffee.

How I feel after drinking each certainly supports this notion. Any actual facts to back this up?

You're right, as far as typical drinks are concerned (e.g., 16 oz of regular drip vs. 2 oz of espresso), but not by volume.

http://www.cspinet.org/new/cafchart.htm.

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Actually, not so much, if you think of it "per volume." According to that chart, a Starbucks grande coffee has 20 mg of caffeine per ounce. A doppio espresso has roughly 23 mg per ounce. So, if you were to drink 16 oz. of espresso, you'd be getting about 369 mg of caffeine compared to 320 mg in that grande Starbucks coffee. Come to think of it, with 17 final exams to grade staring me in the face, 16 oz of espresso is sounding pretty good right about now. . .

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I doubt the accuracy of that chart. I think that 6.5 oz for a "doppio" from Starbucks is a misprint.

http://www.energyfiend.com/caffeine-content/espresso

I just did a quick Google, and the above link is a site from Australia, where they drink predominantly espresso drinks.

The "problem" with espresso is that the caffeine content can vary greatly, depending on how it's prepared. This isn't the best analogy, but it's like putting a number on the grams of "char" on a 16 oz. steak. The amount of char obviously depends on how it was cooked. That's why any figure on the amount of caffeine in espresso is questionable.

I've always believed that the misconception that a shot of espresso has about the same amount of caffeine as a cup of coffee comes from the "shot of hard liquor equals a glass of beer or glass of wine" rule of thumb. A shot of espresso generally has less than half the caffeine of an 8 oz cup of drip coffee. YMMV.

As mentioned earlier, espresso extraction takes (or more accurately should take) 20-30 seconds, instead of the 3-5 minutes for "regular" drip-style coffee.

What effects the amount of caffeine in espresso? How much coffee (grounds) used makes a difference. Roast degree (light or dark) matters. Water temperature matters. Water pressure matters. Density distribution in the espresso grounds matters. SHAPE of the espresso grounds "puck" (extraction space) matters. I could go on.

It's safe to say, without applying any actual numbers: a long (beyond 30 seconds) and thin (in body/viscosity) extraction will have as much as twice the caffeine of a shorter (time), thicker espresso. More specifically, an overextraction (putting too much water through the coffee grounds), which can be the result of one of a number of different factors, will yield higher caffeine extraction.

Hope this helps.

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