WHEN consumers tasted Diet Rite cola in 1958, and many puckered up at the bitter aftertaste, it began a half-century quest - still continuing - to produce a diet soda that didn't taste like one.
America since has landed a man on the moon, corralled the laser for medical use and developed the World Wide Web. But formulating the perfect diet soda is still a work in progress - the latest effort being the Coca-Cola Co.'s launch of Coca-Cola Zero.
Diet brands are the fastest-growing segment of the soda market. Last year, diet sodas made up 29 percent of the market, compared with 71 percent for regular-calorie soda, according to Beverage Digest, a trade publication. Sales of diet sodas are going up, while regular soda sales have been slipping - evidence that there are plenty of loyal diet drinkers, especially women, who like the taste or will tolerate it to save a few calories.
Still, Coca-Cola Zero is carefully avoiding labeling itself as diet. Its marketing is geared to a demographic, such as young people and the most macho of men, who see a stigma attached to the word diet.
"We made a point of not calling it diet," said Scott Williamson, a Coca-Cola spokesman. "There are a group of folks out there, primarily young adults, who for a lot of reasons, some taste, some brand personality, won't drink diet sodas. They may not like them because of the taste or stigma attached to the word 'diet.'"
With Zero, Coca-Cola says it has finally been able to create a diet soda that tastes like the classic version of the 109-year-old soda. Like other recent introductions in the diet-soda market, Coke is seizing on advances in artificial sweeteners that make them taste more and more like sugar. Beverage companies are using new sweeteners, such as Splenda, and better blending existing sweeteners. Coca-Cola Zero, for instance, combines aspartame with acesulfame potassium (ace-k).
"You're seeing a wider array of sweetener alternatives," said Gary Hemphill, managing director of Beverage Marketing Corp., a New York research and consulting firm. "There are more good options than there ever have been. Sometimes, the sweeteners work even better in tandem as blends."
Royal Crown Cola's Diet Rite was the sole diet soda on the market for several years until Coca-Cola followed with Tab in 1963. The hot-pink cans suited the era in which it was introduced. Pepsi-Cola introduced its first diet soda in the 1970s.
The first diet sodas were sweetened with a combination of the artificial sweeteners cyclamates and saccharin. The drinks didn't take off as quickly as manufacturers hoped, but fast-food hadn't become a mainstay and obesity wasn't yet considered a national concern.
Cyclamates were banned by the Food and Drug Administration for a short time beginning in 1970 because of concerns that they caused cancer. Soda makers turned to saccharin, which consumers complained had left even a more bitter aftertaste. Attempts to mix it with sugar didn't satisfy customer complaints. Saccharin was banned, from 1977 to 1991, because of claims that it was carcinogenic.
The introduction of aspartame in 1982 was a turning point for the industry, because it tasted more like sugar and wasn't burdened by cancer worries.
"The introduction of aspartame in the early '80s made Diet Coke and Diet Pepsi into very big brands," said John Sicher, editor and publisher of Beverage Digest.
Industry experts expect the variety of diet sodas to continue to grow as tasting technology advances. Similar developments have influenced the toothpaste world, where flavors such as cinnamon and vanilla are becoming more common.
"Taste is a huge, huge thing," said Jim Trebilcock, senior vice president of marketing for Texas-based Cadbury Schweppes Americas Beverages, the maker of Dr Pepper, 7UP and other soda brands. "First and foremost, the American public wants a good-tasting diet soda."
It's not enough anymore for sodas to have just one diet version. Coca-Cola has nine varieties, including Diet Coke with lime or lemon, diet Cherry Coke, diet Vanilla Coke and a low-carb version. Pepsi has three and Dr Pepper has two, including the recently introduced Cherry Vanilla Diet Dr Pepper.
Diet Coke still has many loyal drinkers, mostly women who have included the beverage in their diet for years. Coca-Cola is hoping to tap into a new market with its new zero-calorie version. This year, the company tried to tap the low-carb crowd with the introduction of Coke with Splenda.
It has rolled out an extensive marketing campaign, including a remake of its award-winning 1970s commercial jingle, "I'd Like to Buy the World a Coke." The new version: "I'd like to teach the world to chill, and take time to stop and smile."
Analysts caution that there is some risk of saturating the market and confusing consumers with so many variations of a product.
"There is nothing riskier in business than trying to introduce a new product," said Chuck Donofrio, chief executive officer of Carton Donofrio Inc., a Baltimore advertising and marketing firm. "But the potential awards are huge and that's why people are willing to take the risk of failing."