There’s a longstanding belief – legend- that the Coca Cola that comes out of McDonald’s fountain machines tastes better than the real-deal bottled and canned stuff. A scientist reveals all about the chemistry and physics of fizzy drinks…
I’ll bet you thought it’s easy to set up a soda fountain. Nothing could be further from the (largely hidden) truth! A food scientist braves the dark hallways of soda’s secret castle to reveal what makes for a perfect cup of fizzy stuff!
Many factors in play
There’s much more to the perfect soda than water, flavouring and carbon dioxide. But any of those can affect the flavour and mouth feel of your fountain beverage.
That’s why a ‘fountain’ Coke at McDonald’s tastes better than the stuff out of a commercially-filled can or bottle. And Fast Food joints go to great lengths to achieve the perfect combination of flavour dilution, water hardness and temperature, CO2 pressure… And even the size of their straws.
Water is critical
Food Scientist Abby Thiel told Parade: “Soft drink [vendors] will usually have their own water supplier or a filtration system to increase the quality of water. Most often, chlorine is removed as it can result in a ‘disinfectant’ taste.”
But the fundamental nature of the water is also up for adjustment…
“The water hardness will be adjusted since it affects the acidity of the drink, and iron will be removed to limit color and flavor defects. Without this treatment, the end result is a Coke that has off-flavors and aromas due to […] inconsistent water.”
Commercial soda bottlers may make some modifications to the water they use, but rarely take same care as fountain proprietors. And like the fountains at your fave Fast Food outlet, the bottlers are using the same water that comes out of your taps at home.
Flavour strength fluctuations
On the other hand, the flavour strength of bottled Coke never varies. The bottlers make sure of that with multiple quality control checks.
At the restaurant, though, different employees may adjust the flavouring ‘injector’ differently when connecting the machine to the mixing system. Some will err on the side of generosity, turning it up, thinking the resulting fizzy fill will taste better. But that usually results in overkill, producing a hard, heavy taste. With what some folks have called a ‘woody’ or ashen edge.
The physics of fluid dynamics
It’s not all chemistry. Long experience and experimentation taught McDonald’s that even the diameter of the straw they give you makes a palpable difference in the flavour of your soda.
Accordingly, McD’s has its straws made with a particular diameter that McExperts say optimizes the flavour and mouth-feel experience: Their straw, they claim, “is slightly wider than a typical straw so all that Coke taste can hit your taste buds.”
‘Made to order’
Another reason sodas out of the fountain dispenser at Fast Food joints taste better is, they’re ‘made to order’ – mixed as they come out of the spout.
Neither can you discount the importance of serving temperature. Which is why most fountain dispensers regulate the temperature of both the waster and flavouring ‘syrup’ that goes into the blend. McD’s formula also adjusts for the diluting effect of melting ice.
My take
So… Next time you pour yourself a cup of fizzy bev at your go-to Fast Food outlet, take a moment to appreciate everything that goes into making that quaff as perfect as possible!
~ Maggie J.