Prepare to be buzzed- even if you ordered decaf.

(submitted by Amisha)

Dave Yoder for The New York Times

You may be getting an unwanted jolt from that morning decaf. Coffee sleuths from Consumer Reports recently tested cups of decaf ordered at Dunkin' Donuts, Starbucks, Seattle's Best Coffee, 7-Eleven, McDonald's and Burger King. They visited six locations of each chain, evaluating 36 cups of decaf in all.

A regular cup of coffee has from 85 to 100 milligrams of caffeine. Most of the 10- to 12-ounce decafs tested had less than five milligrams, the magazine reports in its November issue. But one decaf from Dunkin' Donuts contained 32 milligrams of caffeine — about the same amount in 12 ounces of Coca-Cola Classic. A cup of Seattle's Best was found to contain 29 milligrams of caffeine, while a tall Starbucks decaf packed 21 milligrams. Results varied at each chain, but the magazine found that the decaf at McDonald's consistently had the lowest levels of caffeine.
It's long been known that the decaffeinating process doesn't eliminate 100 percent of the caffeine in coffee, but there are no standards for acceptable levels in brewed decaf. Last year, University of Florida researchers also tested several 16-ounce servings of decaf, finding the caffeine content ranged from nine to 14 milligrams, according to a study published in the Journal of Analytical Toxicology.

By testing nearly four times more cups of coffee, Consumer Reports showed there is wide variability in caffeine levels in both decaffeinated and caffeinated coffees. Notably, even the caffeinated coffees purchased at the chains varied widely in terms of caffeine content, ranging from just 58 milligrams all the way up to 281 milligrams.

The findings are important for people with certain health issues. Caffeine can increase heart rate, interfere with sleep, cause heartburn and increase anxiety, and heavy consumption isn't advised for women who are pregnant or breastfeeding and for those who take certain medications. The findings show that one or two cups of decaf will contain some caffeine, but probably not enough to cause a health concern. Still, people who drink several cups of decaf coffee a day may be getting far more caffeine than they bargained for.