The tradition of the winner drinking milk in victory lane began because Louis Meyer liked buttermilk.
The three-time Indianapolis 500 winner drank some buttermilk in victory lane in 1936 because it was a hot day, he was thirsty and he had gotten into the habit of drinking buttermilk regularly. An executive with what was then called the Milk Foundation saw a picture of Meyer drinking buttermilk in the sports section of his newspaper the following day. He thought Meyer was drinking regular milk, and he was thrilled. He took steps to make sure it would happen in subsequent years as a marketing promotion and the rest is history.
Reports show that milk was part of the victory lane ceremonies between 1937 and 1941, and then again in 1946, the first year after World War II, but there are no records of the winner drinking milk between 1947 and 1955.
The practice was revived in 1956 and continues to this day, as the American Dairy Ass’n has a long history as an IMS partner.