Why Coke tastes better at McDonald's than anywhere else

Their partnership was so close that Coca-Cola began customizing it's delivery system for McDonald's. While other restaurants received Coca-Cola in plastic bags, Coca-Cola used stainless steel tanks for McDonald's. People now suspect it's these stainless steel tanks that preserves the freshness of Coca-Cola as its being transported all around the world.
Further, once the Coca-Cola arrives to a McDonald's location, it goes through another specialized process.
First, there's the use of filtered water. According to the McDonald's website, "In order to ensure our drinks are always meeting a gold standard, we filter all the water before it enters fountain dispensers."
The website goes further to state, "The water and Coca-Cola syrup are pre-chilled before entering our fountain dispensers with the ratio of syrup set to allow for ice to melt."
This chilling process is critical as it ensures optimal CO2 levels in the drink or high levels of carbonation. This means you are guaranteed to get a bubbly, refreshing sip. Let's be honest --- nobody likes flat Coke.
Finally, there's the design of the straw size. The McDonald's website states, "There’s also our straw—it’s slightly wider than a typical straw so all that Coke taste can hit your taste buds."
Needless to say, tremendous thought and planning goes into ensuring the Coca-Cola at McDonald's is of the highest quality. As a result, the Coca-Cola at McDonald's indeed tastes better.