I get a lot of folx looking for comparisons on the caffeine content of tea and coffee. I'm sure some of these are health-conscious folx with concerns about putting bad things in their bodies. But some are from the opposite end of the spectrum - caffeine seekers. I fall somewhere in the middle. I want to be healthy. No, really, I do. But if it means giving up my coffee and black tea, well, I don't think so. What is long life if there's no quality of life, no enjoyment?
Well, anyway, before I wax too philosophic... caffeine is
"an alkaloid (C8H10O2N4•H2O) found in coffee, tea, cacao, and some other plants. It is also present in most cola beverages. Caffeine was discovered in coffee in 1820. In 1838 it was established that theine, discovered in tea in 1827, is identical to caffeine. The drug increases the blood pressure, stimulates the central nervous system, promotes urine formation, and stimulates the action of the heart and lungs. Caffeine is used in treating migraine because it constricts the dilated blood vessels and thereby reduces the pain. It also increases the potency of analgesics such as aspirin, and it can somewhat relieve asthma attacks by widening the bronchial airways. Caffeine is produced commercially chiefly as a by-product in making caffeine-free coffee. (From THC: Encyclopedia)
Caffeine content of beverages and foods varies depending on type and preparation methods. There seems to be no definitive number for comparing coffee and tea, but averaging out all the charts I found, a general comparison for a 6 oz cup would be 100 mg for drip coffee and 70 mg for black tea. Some good lists:
Erowid Caffeine Vault - Caffeine Content of Beverages, Foods, & Medications
Caffeine Comparison Chart - from about.com
All About Caffeine - from answers.com
Now, if you just can't find a beverage with enough caffeine, if you just gotta have that extra-hefty jolt, try adding a little 100% Purity White Crystalline Powder Caffeine to your cup. I don't know if I would want to try this stuff, personally, but hey, they claim it's absolutely the purest stuff. "Just add 1/16 Teaspoon (105 mg.) caffeine powder to juice or soft drinks" and get ready to fly. WeeeeeeeHAAW!