Not every cup of Coke is created equal. If you’re a McDonald’s customer who can’t resist ordering a large Coke with your Big Mac and fries, you may suspect that the soda from the fast-food chain is superior to versions found elsewhere. It’s not childhood nostalgia warping your taste buds: McDonald’s takes steps to ensure their Coke really does taste better than the competitors.

Coca-Cola is serious about preserving its secret formula, and the drink you get at McDonald’s is made from the same ingredients that you’d get in a can from a vending machine. The difference lies in the way McDonald’s treats those ingredients right up to the moment they fill your cup.

Most Coke syrup is shipped to restaurants in plastic bags, but for McDonald’s, one of the company’s most profitable partners, Coca-Cola sends the product in stainless steel drums. This material is better at preserving the ingredients and keeping them fresh by the time they arrive at their destination.

The second reason the Coke at McDonald’s tastes so good has to do with temperature. Instead of storing water for the soda in the soda fountain like many restaurants do, the chain uses insulated tubes to transport it from the fridge directly to the dispenser when it’s ready to be poured. In addition to tasting great, colder liquid is also better at trapping CO2 bubbles and keeping drinks fizzy for longer.