Kellogg's Corn Flakes came from stale dough left out overnight

In 1894, Dr. John Harvey Kellogg, superintendent of the Battle Creek Sanitarium in Michigan, was experimenting with a wheat-based granola for his patients' vegetarian diet. One night he was called away, leaving a batch of boiled wheat dough sitting out. The next morning, rather than discarding the stale dough, he sent it through rollers — and got delicate, thin flakes instead of the expected sheet. He baked them and served them to patients, who loved them.

John Harvey's younger brother, Will Keith Kellogg, who worked as the sanitarium's bookkeeper, saw the commercial potential. He persuaded his brother to package the flakes as Granose, mailed to former patients. But John Harvey forbade Will from selling cereal beyond the sanitarium. Will went ahead anyway, founded the Battle Creek Toasted Corn Flake Company on February 19, 1906, and added sugar to the recipe — a move that broke the brothers' relationship for good.

John Harvey sued Will for the right to use the family name. The legal battle lasted over a decade, ending in December 1920 when the Michigan Supreme Court ruled in Will's favour. By 1909, Will's factory was producing 120,000 cases of Corn Flakes daily. His innovative advertising — including the first inside-the-box prize for children in 1909 — helped build a global brand. During the Great Depression, Will introduced a six-hour, four-shift workday to employ more people.

Corn Flakes became the foundation of one of the world's largest food companies. Kellogg's went on to produce Rice Krispies, Frosted Flakes, and Pringles. In 1930, Will established the W. K. Kellogg Foundation with an initial $66 million donation. By 2023, the company's revenue was $14.2 billion, and it split into two companies, Kellanova and WK Kellogg Co, each acquired by Mars and Ferrero in 2025.