Which version of Coca-Cola do you prefer? That was the question everyone was asking when new Coke debuted on store shelves for a brief period of 79 days in 1985.

For 99 years, Coca-Cola had used the same basic recipe developed by chemist Dr. John Pemberton (1831-1888) of Atlanta, Ga., a syrup containing extracts of coca leaves and kola nuts. Injured in battle during the Civil War, Pemberton fought an addiction to morphine used to combat the pain and created several tonics he hoped would replace morphine.

His partner and bookkeeper, Frank M. Robinson, named the tonic Coca-Cola for the two main ingredients and devised the word mark using his own Spencerian hand script. The syrup was mixed with soda water and sold for 5 cents a glass at the nearby Jacob’s Pharmacy in 1886.

Nearly bankrupt, Pemberton sold portions of the rights to his recipe, with new investor Asa C. Candler (1851-1929) purchasing the final portion shortly before Pemberton’s death. Candler bought out the other investors to obtain sole right to the recipe and registered the name Coca-Cola in 1893. The abbreviated name “Coke” was registered in 1945.

The battle between Coke and rival Pepsi-Cola peaked during the Pepsi Challenge in 1981, when Pepsi did a nationwide taste test and advertised that more cola drinkers preferred the taste of Pepsi over Coke.

While Coca-Cola executives Roberto Goizueta and Donald Keogh would claim that the Pepsi Challenge had little to do with the change, on April 23, 1985, Goizueta held a press conference at New York City’s Lincoln Center proclaiming the new formula of Coke to be “smoother, rounder, yet bolder – a more harmonious flavor.”

Along with the new formula, a new logo was designed, adding an outline of silver to the iconic red-and-white branding. Ads proclaimed, “Great New Taste! The Best Just Got Better!”

But die-hard Coke drinkers disagreed in a big way. Sales of the old formula flew off the shelves as customers stock-piled a reserve. Sales of the new version fell flat, and company phone lines garnered thousands of complaint calls a day.

By July 23, executives admitted they hadn’t listened to their customers and the original formula would return, now named Coca-Cola Classic. New Coke, renamed Coke II in 1992, stuck around until 2002 before being discontinued.