(CNN)It's an automatic reflex for many of us: obediently tapping a few times on a can of beer or soda to stop it from frothing over.
Festive PSA: Tapping a can of beer doesn't stop it bubbling over, scientists say
But researchers in Denmark have discovered that we've been wasting our time. Tapping on a can of shaken beer makes absolutely no difference to whether it fizzes all over your party outfit.
The team from the University of Southern Denmark in Odense conducted a randomized test using 1,000 330-milliliter (11-ounce) cans of beer. The cans were placed into one of four groups -- unshaken/untapped, unshaken/tapped, shaken/untapped and shaken/tapped.
The beers were shaken for two minutes using a machine that was set to simulate the effect of riding a bicycle for 10 minutes, a popular Danish method of transporting beer.
The cans were hit three times on the side and opened after roughly a minute, with the teams weighing them before and after opening to find the mass and assess the level of beer loss.
The scientists chose to tap on the side of the can rather than on the top, because it acts on a larger surface area.
The study found "no evidence to support the hypothesised beer-saving effect of tapping," the researchers concluded, adding that the only apparent way to avoid a beer-frothing incident was to wait for bubbles to settle before opening the can.
"The idea came from as a teenager opening can of soda and later beer," Elizaveta Sopina, the lead researcher on the study, told CNN. "It's just what people do. I did it, and then I started to question whether it was actually true and effective or not.
"I was surprised, but not disappointed ... it's good to be evidence-based in your behavior."
Sopina, who is doing a post-doctorate in health economics, gathered a