Why does tapping on a soda can work

Finally, they weighed the can again to determine the amount of beer that had been lost. The results are palate tickling. Sopina and co compared the amount of beer lost for tapped and untapped cans that had been shaken and found no statistical difference—both lost about 3. They also found no meaningful difference between the cans that had not been shaken—when opened, they lost about 0.

The obvious conclusion is that can tapping does not reduce foaming, a result that must be a considerable disappointment for bicycle-riding, beer-carrying Danes.

And Sopina and co have some ideas. One is that flicking does not provide enough energy to dislodge bubbles, perhaps because the energy is absorbed by the aluminium can and the bulk of the liquid. Unfortunately, the team does not appear to have measured the energy imparted in this way, cleverly leaving the way open for more research.

Another possibility is that an assumption behind the tapping theory—that the bubbles associated with foaming must be attached to the wall of the can—is incorrect. That would prevent them from rising at all. Indeed, some anecdotal evidence supports this. If proteins are responsible, Sopina and co suggest that beer could be treated to prevent foaming by denaturing the relevant proteins, perhaps by heating the beer before it is cooled. However, the proteins play an important role in the flavor and mouthfeel of beer.

And therein lies an entirely new research project for Sopina and her colleagues, or indeed any other specialists. Beer-related research is a glass that is truly bottomless. Ref: arxiv. A Randomised Controlled Trial.

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Discover special offers, top stories, upcoming events, and more. Sharply tapping the top of an open beer bottle with another has a similar effect, commonly resulting in a colossal gush of beer foam. The debate of tapping aside, the actual material that the container is made from may also reduce gushing. This information is relevant when such bubbles are thought to be the cause of gushing.

Another important factor when it comes to the level of gushing is the stabilisation of the bubbles caused by the presence of large molecules in the drink. This is why some beers have long-lived foam heads compared to the short-lived bubbles at the surface of, say, sparkling water.

But such foam stabilising agents are a conversation for another day. So this summer why not try different ways of opening your fizzy drink — and see how much of it you end up wearing. Time heals most things, especially when one of those things is delinquent carbonation just itching to have at you.

Last updated: 21 July Sources: Tew, J. Fact Checks. Tapping a Soda Can. Top Fact Checks.