I just drink it for the taste

So you are probably saying to yourself, "hey, I drink a lot of coffee, but am I really getting all of the caffeine that I need?" Well, here's some information from The Atlantic's new Food Section that may be of use to you:

In a couple of studies testing 90 different Arabica cultivars, the caffeine content varied between 0.42 and 2.9%. My morning cup would then vary between 84 and 580 milligrams, depending on which of these varieties was in my cup.

If your morning cup came from a commercial roaster who included Robusta in the blend, we have another level of complexity. Caffeine content in these coffees, in one study, varied between 1.16 and 4.0%. A straight 12 oz. cup, using 20 grams of the 4% coffee, probably wouldn't taste very good, but would definitely provide more buzz: 800 milligrams of caffeine.

As with most things, the more one learns, the more complex a topic becomes and, in a sense, the less one knows. To attempt accurate generalization:

• Arabica averages about half the caffeine as Robusta.
• The cultivar determines the caffeine content.
• Degree of roast has no meaningful effect on caffeine.
• An espresso made from 100% Arabica, on average, has about 70 milligrams of caffeine per shot; a 12 oz. cup of drip coffee made my way in a press pot, using two scoops of coffee per 12-ounce cup -- would have 200 milligrams.

Beware of taking this information very far, because individual responses to caffeine differ widely. Caffeine is metabolized faster by men and slowest by pregnant women. Body weight and eating will affect caffeine absorption.