Why is milk in gallons but Coca-Cola is bottled in litres?

The American non-public system of measurement has always been criticized by other countries in the world. Not sure if any friends who have lived in the United States have noticed that the milk they sell is in pints/quarts/gallons, while carbonated drinks are in 2 litre bottles? Why is it that despite being in the same country, two liquids are packaged and distributed with different metering systems?

This is just one of many examples of American’s measurements. Carbonated drinks happen to meet a short historical window when the metric system seems to be about to take over in the United States.

In the early 1970s, Coca-Colas sales were about 10 times that of Pepsi. Pepsi, eager to grab more market share, began to brainstorm and design a new and more eye-catching bottle to compete with the classic curved glass bottle of Coke.

They found nothing.

The Coke bottle is not only visually distinctive, but also in the entire life cycle of the product, from the bottling conveyor to the vending machine, its design is also very reasonable and not easy to break.

Pepsi’s new marketing director at the time, John Scully, who later wrote his personal experience into a book "Moonshot!”, revealed after careful analysis that he found that there was no bottle design better than Coca-Cola. But he did make an interesting discovery that Pepsi consumers were disappointed when finishing drinking.

Scully realized that he didn't need a new bottle design. Instead, what he needed was a bigger bottle. Big, Bottle.

Hence, Pepsi asked the chemical giant DuPont to provide suitable materials. A year later, a 2-litre plastic bottle was born.