If you’ve ever had an ice-cold Diet Coke from McDonald’s, you know how satisfying that first sip is. It’s what leads many people to the drive-thru in the first place. But why does it taste so much better than your Diet Coke at home?

You’re not imagining it: McDonald’s Diet Coke does taste different. The fast-food chain does a few things to differentiate its soda from others.

First, while most restaurants get their Coca-Cola syrup delivered in plastic bags, McDonald’s delivery comes in stainless-steel tanks. This helps to keep the syrup fresher, and no flavors are lost or diluted. Once the syrup arrives, it’s mixed with filtered water and chilled before it goes into the soda fountain.

Some restaurants add the syrup and water mixture to the machine and depend on it to cool the mix. McDonald’s, however, takes that pre-chill step and combines it with the use of insulated tubes. They transport the syrup and water from the fridge to the fountain keeping the drink as cold as possible. While the temperature might not seem important, it is.

Warm soda allows CO2 (aka carbonation) to escape quicker. This means your drink won’t be as bubbly (and fun). Because McDonald’s soda is chilled from start to finish, it’s able to hold more carbonation for a fizzier drink.

The next time you’re craving a McDonald’s specific Diet Coke, there is a reason why. Just in case you can’t make it to your local restaurant, though, you can always try these soda alternatives until your next visit.