Why is Milk Sold in Gallons and Soda Sold in Liters?

There are more ways to measure a foot than many Americans often consider. If you stick to the imperial system, a foot can also be called one-third of a yard. For those using the metric system, one foot is 0.3048 meters. We don't have exact statistics, but we're willing to bet the majority of the world uses the metric system. In fact, a quick Google search implies that only the United States, Myanmar, and Liberia use the imperial system. We digress.

There are liters and quarts and gallons and milliliters and, if you're not careful, it all can get very confusing very quickly. That said, Americans do use some metric measurements for one reason or another. Following that train of thought, we're going to dive into a relatively understated topic. Why is milk sold in gallons and soda in liters?

Marketplace has done the research on this one. In the 1970s, Coca-Cola was beating Pepsi. Apparently, it wasn't just beating; they were crushing Pepsi on all fronts. The Coca-Cola glass bottle design was nearly perfect, and Pepsi started investigating ways to improve their own bottle design.

During this research, they found that households were running out of Pepsi too quickly. Quickly, they pivoted from trying to beat Coke's glass bottle design to figuring out how to bottle more liquid for their consumers. Working with a chemical company, Pepsi wound up utilizing a plastic bottle that was ten-times bigger than a standard, glass bottle of Coca-Cola.

While this was happening, Americans were in a metric system frenzy. There was a movement forming where people wanted to say goodbye to pints and hello to liters. That said, Pepsi's large, plastic bottle was dubbed the two-liter.


The country seemed to be heading in a metric-based direction, and other soda companies saw Pepsi as a liter, err, leader. One company, 7UP, used this pun to their advantage, making their slogan, "Follow the liter."

So why did liters stick for soda and not milk? It turns out that it may be related to location and scale. Companies like Pepsi were producing on a global scale, making metric even more appealing. Milk, though, is often sold locally. Thus, local units of measurement, the gallon, were used for milk. Seems almost too simple, doesn't it?

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