It all started with a request from a parched driver in Victory Lane.

After Louis Meyer won the 1936 Indianapolis 500 on a particularly warm day, he asked for a glass of buttermilk.

In some subsequent years, the winner received a bottle of milk. In 1956, the dairy industry became involved as a sponsor, and the tradition has stuck.

Why can't Indy 500 winners drink buttermilk now?

Though drivers occasionally request buttermilk, it is not an option. In 2019, Brooke Williams, director of communication for the American Dairy Association Indiana, told IndyStar the organization hasn't offered buttermilk as an option since the poll was started in the mid-90s because it's not the drink it was in 1936.

Meyer was drinking milk that was left over from the butter his mother made, according to Williams. That buttermilk was refreshing, rich and creamy. But it no longer exists because dairy products are produced at large plants and the old-fashioned buttermilk is highly perishable.

Modern buttermilk is regular milk with a culture (and sometimes salt for flavor) added to it and, while you can drink it, it has a sour taste and is more often used in cooking.

"(If) we see a driver drink a full glass of buttermilk before the race," Williams said in 2019, "we'll give them some special (consideration). For now, we're keeping it to the three options (of whole, 2% and skim)."

Here is the list of milk for the 2024 Indianapolis 500 drivers

Choice breakdown: 26 go with whole milk, five pick 2% and two pick skim

Marco Andretti, whole

Marcus Armstrong, whole

Tom Blomqvist, whole

Agustin Canapino, whole

Ed Carpenter, whole

Helio Castroneves, 2%

Conor Daly, whole

Scott Dixon, whole

Marcus Ericsson, whole

Santino Ferrucci, whole

Pietro Fittipaldi, whole

Romain Grosjean, 2%

Colton Herta, whole

Ryan Hunter-Reay, whole

Callum Ilott, whole

Kyle Kirkwood, whole

Kyle Larson, whole

Katherine Legge, whole

Christian Lundgaard, skim

Linus Lundqvist, whole

Scott McLaughlin, whole

Josef Newgarden, whole

Alex Palou, whole

Pato O'Ward, 2%

Will Power, whole

Graham Rahal, 2%

Christian Rasmussen, skim

Sting Ray Robb, whole

Felix Rosenqvist, whole

Alexander Rossi, whole

Takuma Sato, 2%

Kyffin Simpson, whole

Rinus VeeKay, whole

This article originally appeared on Indianapolis Star: Indianapolis 500 traditions: Why the race winner drinks milk