After World War II, Coca-Cola held 60 percent of the cola market. By the early 1980s that share had fallen under 24 percent, and younger drinkers preferred the sweeter taste of Pepsi. CEO Roberto Goizueta, who took over in 1980, declared there were no sacred cows, and a secret effort called Project Kansas produced a sweeter formula that beat Pepsi in blind taste tests, even in the loyal Southeast. On April 23, 1985, the company announced the change and stopped making the original. Within weeks it faced more than 40,000 angry letters and calls and a psychiatrist reporting that callers sounded as if a relative had died.

This episode explains why the data pointed one way and the public went the other. Sip tests reward sweetness that grows cloying over a full can, and blind cups strip away the red can, the script logo, and the memories that shape how a drink tastes. It also covers why selling both colas seemed impossible, how Pepsi gloated, and how the return of Coca-Cola Classic on July 11, 1985 sent sales soaring past Pepsi.

• Focus groups contained a furious 10 to 12 percent who pressured others into disliking the change, a warning management chose to downplay.
• Seattle retiree Gay Mullins borrowed $120,000 to found the Old Cola Drinkers of America, yet in blind tests he could not tell the two apart or preferred New Coke.
• Pepsi’s Roger Enrico ran a full-page New York Times ad declaring victory in the cola wars and gave employees the day off.
• Peter Jennings interrupted General Hospital to announce the original formula’s return, and company president Donald Keough answered conspiracy theories with: we’re not that dumb and we’re not that smart.
• When New Coke returned in 2019 as a Stranger Things tie-in, demand crashed the Coca-Cola website and modern reviewers called it refreshing and smooth.