Dear Straight Dope:
Last week my sister and I stopped at a convenience store. She picked up a Barq's Root Beer and I picked up a Pepsi. We got into the car and opened our pops and that's when the argument began. She said "Barq's has bite," and I replied, "It has bite because it is the only root beer with caffeine in it." She said all root beer has caffeine because her boyfriend says so. I told her she was wrong and said, "Root beers have no caffeine, Pepsi has the second least amount, Coke Classic third, followed by Barq's. Jolt Cola has the most caffeine of any pop." She denied this and told me that Mountain Dew had the most caffeine. Since then my sister, her boyfriend and I have been in a constant battle to prove each other wrong, I was just wondering if you could provide some insight on the topic for us. It would be a big help to show them they are wrong.
From my son, the biochemist, with an assist fromSDSTAFF Jill who found many of the Internet sites:
Ah, the power of the Internet, where specious, spurious, and suspicious information can be found with a click of the wrist. Present company excluded, of course.
Let’s tackle these one at a time. First off, coffee versus tea.
It’s tricky to directly compare them. The amount of caffeine in a cup of coffee or tea depends on a bunch of factors, in particular the type of bean/leaf (some species are more loaded than others) and the amount of brewing/steeping time (the stronger your drink, the more caffeine is in it.)
In general, however, the dread "average" cup of coffee contains more caffeine than the "average" cup of tea. According to the Stash Tea Company (http://www.stashtea.com), a 5-ounce cup of percolated coffee contains 40-170 mg, while a 5-ounce cup of brewed tea (imported, of course) contains 25-110 mg of caffeine. So, the average weakest or strongest cup of coffee contains about half again as much caffeine as the average weakest or strongest cup of tea.
Of course, there’s a lot leeway in those numbers. It wouldn’t be hard to brew a big, tough cup of tea with more caffeine than a piddly little cup of wimpy coffee.
More interesting (to me, anyway, but then, I’m not a big caffeine drinker) is that, when compared in equivalent amounts, tea leaves tend to contain more caffeine than coffee beans. Caffeine, apparently, extracts more readily from beans than from leaves. Ah, the miracles of the Plant Kingdom.
Now, as to the question about soft drinks ("pop" in my childhood, now "soda")–well, you win a few, you lose a few.
A quick online search led me to http://www.nsda.org, the Home Page for the National Soft Drink Association. After taking a moment to come to grips with the fact that such a thing actually exists, I tracked down caffeine content info. They don’t give listings for specific brands, just for general types. Thus I was able to determine that root beer, in general, has no caffeine. You’re half-right.
Then came the question of Barq’s. Now, understand that I’m a trained, professional chemist. I’ve done caffeine extractions before. It’s not that hard. So, I acquired a 12 oz. can of Barq’s Root Beer from the cafeteria, and, in a few spare moments, performed a rapid ocular scan to validate your hypothesis. While I don’t advise you try this at home, it’s quite easy to do. Take the can, turn it around, and read the ingredients.
"Caffeine." Boom. You’re done. Barq’s Root Beer does contain caffeine (though, interestingly, a similar scan of Diet Barq’s revealed that it does not. Go fig.)
Of the soft drinks you list, my sources indicate that Jolt Cola does have the most caffeine (71.2 milligrams per 12 oz. can). It’s followed by Mountain Dew (55 mg, but apparently no caffeine in Canada), then Coca-Cola (45.6 mg), then Pepsi (37.2 mg), then Barq’s (at 22.5 mg).
As for whether or not Jolt Cola has the most caffeine of any soft-drink, well, you’ve got to consider just how many soft drinks there actually are out there. To provide scope, I recommend http://www.bevnet.com. There’s a lot out there, thus I’m not sure what qualifies as "the most."
The listing I found that offered up the amounts of caffeine above lists Jolt at second place, under something called "Afri-Cola," which it claims has "100.0 (?)" mg of caffeine per 12 oz. bottle. Some digging revealed that Afri-Cola is a European import. Some more digging turned up a number of 250 mg per (roughly) 12 oz. bottle, which is approximately equivalent to drinking 12 oz. of average strength coffee, or popping one tablet of Vivarin (200 mg per pill).
As for what soda has the least caffeine, well, it’d pretty much be a tie between the myriad sodas that don’t have any–lemon-lime sodas (Sprite, 7-Up), orange sodas, root beers, etc.
I was going to offer that if you really want to know what has the least caffeine, you should maybe aim for water. However, that’s not necessarily true anymore. Caffinated water is now available (God bless America). My personal favorite brand is called Krank2O (favorite not because I drink it but because I really admire the name), which clocks in at about 70 mg per 12 oz. serving. I heartily advise against brewing coffee with this stuff.
For more information, and there’s a lot of it out there, check out http://aomt.netmegs.com/coffee/caffaq.htm.
— Son of
Send questions to Cecil via firstname.lastname@example.org.
STAFF REPORTS ARE WRITTEN BY THE STRAIGHT DOPE SCIENCE ADVISORY BOARD, CECIL'S ONLINE AUXILIARY. THOUGH THE SDSAB DOES ITS BEST, THESE COLUMNS ARE EDITED BY ED ZOTTI, NOT CECIL, SO ACCURACYWISE YOU'D BETTER KEEP YOUR FINGERS CROSSED.