Tock. Tock. Tock. Klack: That's how opening a beer can sounds to experienced drinkers. Before opening the can, lightly beat the lid, the bottom or the sides of the can with your finger to prevent them from spraying the beer. But does that really work?
According to researchers from Denmark, the supposed benefits have never been tested with scientific methods. So they have taken up this research question and have now published their findings on the platform Arxiv. The website is less well regarded than the large specialist magazines, where each contribution is critically reviewed by peers. But maybe the beer can study is not for high-caliber journals anyway.
A beer manufacturer supported scientific research with more than a thousand cans of beer. These had to be opened before opening on the scales. Then the researchers put half of the cans in a mechanical shaker, the other half remained in the condition in which it was delivered.
The actual test was done by students who volunteered. One group received the shaken cans, the others the unshaken ones. Half of the volunteers in both groups should tap on the side of a can three times before opening it. The others opened without knocking. Then all cans were weighed again to see how much beer bubbled out of the can when opened.
Result: The knocking brought no advantage, no matter whether the cans were shaken before or not. Whether the experimental setup can be transferred to other carbonated drinks in cans, is not scientifically proven, since these were not part of the experimental setup.
The beer was given away to the researchers after the test on the campus of the university.