Failure 16 · Business failures
The new recipe that won the taste test and lost the customers
Coca-Cola changed its formula in 1985 after large taste tests, but loyal drinkers were furious, and the original came back 79 days later.
- Coca-Cola
- Atlanta, Georgia, United States
- 1985
- 3 min read
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Before you readWhat would you do?
An AI tool tested two versions of your restaurant's menu on 500 online visitors and found people clicked more on the new one. Your manager wants to remove the old dishes from all branches tomorrow. What would you suggest?
Pick an answer now. The file tells you whether you were right.
01The file in one minute
1The test
Coca-Cola tested a sweeter recipe with nearly 200,000 people, and more preferred it in blind sips.
2The change
On 23 April 1985 it replaced the original. Angry calls and tens of thousands of letters followed.
3The U-turn
On 11 July 1985, 79 days later, the original returned as Coca-Cola Classic.
4The lesson for AI
A test answers the question it was built for. Check that it matches the real decision before you trust it.
02Timeline
Early 1980s
Pepsi's blind taste tests put pressure on Coca-Cola.
23 April 1985
Coca-Cola announces a new formula and stops making the old one.
May to June 1985
Angry calls and letters pour in, and some people stockpile the old drink.
11 July 1985
The company announces the original will return as Coca-Cola Classic.
03What happened
In the early 1980s Coca-Cola was losing ground to Pepsi, which ran blind "Pepsi Challenge" taste tests where many people preferred the sweeter Pepsi in a single sip. Coca-Cola developed a sweeter recipe and tested it with nearly 200,000 consumers, according to the company. In blind tests, more people preferred the new taste.
On 23 April 1985 the company announced the new formula and stopped making the old one. Many customers reacted with anger. The company was flooded with phone calls and tens of thousands of complaint letters, and some people stockpiled the old drink. For many, the old Coke was tied to memories and identity, and they felt something had been taken from them.
On 11 July 1985, 79 days after the change, Coca-Cola announced that the original formula would return as "Coca-Cola Classic". Sales of the classic version soon passed both the new formula and Pepsi.
04Why it failed
The tests measured what they were designed to measure: which drink people liked in a quick sip. They did not ask how people would feel if the old drink disappeared for good. The data was real, but it answered a narrower question than the decision being made.
The AI angle: AI systems are trained and tested on a measure someone chose. A model can score well on that measure and still miss what people care about. Before you trust a result, ask whether the test matches the real decision.
The idea behind this caseLesson: Spreadsheets and data →
05Lessons for anyone deploying AI
- Before acting on a test, write down the real decision and check that the test asks the same question.
- Ask customers how they would feel about losing something, not only which option they prefer.
- Roll out big changes in one area first instead of everywhere at once.
- Keep a way to go back, and be ready to use it quickly if the response is bad.
07 — Sources
- New Coke: The Most Memorable Marketing Blunder Ever? · The Coca-Cola Company · 2012-11-14
- New Coke debuts, one of the biggest product flops in history · History.com (This Day in History) · 1985-04-23