They make eyes pop and jaws lock. They make people cringe and complain -- and they're turning children and adults into crybabies.
Nonetheless, ultrasour gum balls, with names like Eye Poppers and Cry Baby, Lock Jaw and Goose Bumps, are disappearing from store shelves this summer faster than manufacturers can provide them.
Shocking the taste buds with 30-40 seconds of unmerciful sourness before the fruity sweetness kicks in, the gum balls have an appeal for children that's hard for parents to understand.
"Your eyes start to tear," explains Ben Granofsky, 7, who says that Eye Poppers are popular with his Lake Shore Clinic League baseball team in Pasadena. "When you get past the sour part, then it's the bubble gum part -- it's not that sour and it doesn't make you feel that bad."
"I think they're awful," said Karen Stiltner of Pasadena, whose son, Ryan, 8, is a big fan of Eye Poppers. "They're very bitter . . ."
In fact, Mrs. Stiltner never got to the sweet bubble gum center of the Eye Poppers: "She tried one and she spit it out," explained her 6-year-old daughter, Amy.
The gum balls, manufactured by companies such as Leaf candy company, Zeebs and Philadelphia Chewing Gum Corp., target youngsters ages 8 to 12. And they are so sour they come with humorous warnings. The Cry Baby extra-sour bubble gum label offers the message "Caution: You'll only cry for 40 seconds -- Stay with it!" while Lock Jaw's label boasts the description "jaw locking gum balls, perfect for the big mouth."
The bitter punch is created by a coating of sugar and citric acid. The acid, according to Peter Putnam, a sensory analyst in the Research and Development division of McCormick & Co., causes the sensation of astringency -- like the dry feeling experienced when eating unripened fruit.
So why are kids eating up the super-sour sensation, when most adults find it unpleasant?
Some researchers believe that adults and children may sense tastes in varying degrees, but the idea is controversial. Studies have demonstrated decreased sensitivity to taste in children ages 7 to 11 while others have shown no differences in taste sensitivity before age 60.
Other experts figure a liking for the super-sour gum is acquired. "It's similar to how adults enjoy the pain of hot, spicy foods and kids don't. In this case, kids like the sour gum balls and adults don't," says Peter Putnam, sensory analyst at McCormick.
Or the attraction of the gum balls may lie with psychological factors. "There's a certain thrill-seeking quality when you're younger that not all adults lose, but that adults move away from," says Dr. Leon A. Rosenberg, a psychologist at the Children's Medical Center at Johns Hopkins University.
Dr. Rosenberg compares the attraction of the gum balls with that of horror movies. "They're not uniformly liked by children and disliked by adults, but horror movies do disproportionately appeal to younger people," he said.
Competitiveness may be another explanation. "Kids like to out-do each other," he says, adding that the mentality of children is " 'I can chew it -- can you?' "
"One of my friends at school dared me to try one. . . . I did so I wasn't a wimp," Ryan Stiltner said. Now Ryan is hooked, and says he chews about 20 Eye Poppers a week.
That kind of consumption puts dollar signs in the eyes of those in the candy business.
"We believe the whole sour gum ball business is going to reach $70 [million] to $80 million this year," said Daniel Munoz, a product manager for the Leaf candy company, makers of Eye Poppers. That's approximately 1 billion gum balls at 5 to 10 cents apiece, he said.
The gum is selling so fast, Mr. Munoz said, the company is working on an allocation basis with distributors: Instead of customers telling Leaf how many of the Eye Poppers they want, Leaf tells the distributors how much they are allowed to buy, based on the quantity available.
And although summer -- with the school year over and teachers' rules forgotten -- is a popular time for gum chewing, Mr. Munoz expects the demand for Eye Poppers to last at least through November.
In fact, during the last school year, enterprising youngsters who recognized the financial opportunities in this high demand/low supply market were buying Cry Baby for a nickel apiece and selling them to classmates for 25 cents, according to Carol Parrott, spokeswoman for the maker of Cry Baby, the Philadelphia Chewing Gum Corp. in Havertown, Pa.
But like many things, what's fun isn't always good for you.
Dr. John Graybeal, the director of General Dental Services at Johns Hopkins Hospital, has not seen patients with complaints directly related to the sour gum balls but, based on their ingredients, sees them as potentially damaging to teeth.
"The acidity of it from the citric acid standpoint, as well as from the sugar, would be damaging as far as tooth decay or even erosion, depending on the amount of exposure," Dr. Graybeal said.
And the citric acid could etch away the enamel on the inside edge of the teeth, says Dr. Paul Breslin of the Monell Chemical Senses Center in Philadelphia.
Mr. Munoz, of the Leaf company, disagrees. "It's no different from chewing on a lemon," he said. "The ingredients we use [citric acid and natural sugars] are ingredients that are currently being used by consumers in lemons, limes, apples."
Whether sour gum balls remain a stock item on the candy counters everywhere or are just a passing trend depends upon whom you ask.
"I think it's a fad," said Mrs. Stiltner. Ryan disagrees and is certain when he grows up, he'll still be sweet on sour.