Dropped Your Beer? Research Says Tapping it Won’t Stop the Foam – the Science of Fizz
Sad but true. According to a recent research study, science says that tapping a beer on the top or bottom after a drop or shake, won’t prevent (or reduce) the foam, fizz, or spray…
By Dustin Miller on Dec. 19, 2019
So you dropped a can of beer right before you were going to open it and now it’s all shook up – but you’re not scared, you have a secret ritual that “taps that fizz away”…or so you thought.
It turns out that tapping your beer has no significant affect on reducing or stopping the fizz from a beer that’s been shaken or dropped. Researchers at the University of Southern Denmark in Odense conducted a randomized test using 1,031, 11oz/330ml cans of Carlsberg beer and found that there is no evidence to support “the practice of tapping a beer prior to opening reduces fizz/foam.” Researchers have concluded that the only way to avoid a beer-frothing explosion was to wait for the bubbles to settle before opening the can (or to not butter-fingers that can in the first place).
About This Beer-Tapping Science & Research Study
- 1031 cans of cans of beer of 330mL were randomised into one of four groups:
- Unshaken / untapped (n=256),
- Unshaken / tapped (n=251),
- Shaken / untapped (n=249), or
- Shaken / tapped (n=244).
- Beers were shaken for 2 minutes to simulate the ride in a backpack of a cyclist.
- Shaken & tapped beers were tapped three times on its side with a single finger.
- We compared tapping versus non-tapping for cans that had been shaken for 2 minutes or were unshaken.
- The main outcome measure was beer loss (in grams)
- Results:
- For shaken cans, there was no statistically significant difference in the mass of beer lost when tapping compared to not tapping (mean difference of -0.159g beer lost with tapping, 95% CI -0.36 to 0.04).
- For unshaken cans, there was also no statistically significant difference between tapping and not tapping.
- Conclusion: These findings suggest that tapping shaken beer cans does not prevent beer loss when the container is opened. Thus, the practise of tapping a beer prior to opening is unsupported. The only apparent remedy to avoid liquid loss is to wait for bubbles to settle before opening the can.
Why does beer foam or froth when dropped or shaken?
It all comes down to carbon dioxide and the chemistry (and physics?) of moving carbon it out of a liquid (as carbonic acid) into a gaseous state (as carbon dioxide). Typically, it’s difficult to remove gas from an undisturbed liquid because the liquid’s surface tension prevents the rapid change (or so they say over at Scientific America). The gist of it is that energy is required to separate the carbon molecules, from carbonic acid in your drink (and convert it to its gaseous of carbon dioxide). That process is a somewhat slow…unless…you drop or shake the can, introducing bubbles, shock waves and kinetic energy. Then this burst of energy causes a rapid reaction, lots of tiny bubbles, and an explosion of carbon dioxide as it’s released from the beer. This is also why slamming a beer bottle onto a beer bottle creates an instant foam eruption as well.
Image of bubbles reacting in beer and releasing carbon dioxide
How do you STOP a beer from foaming up after you drop or shake it?
The most technical option is…you wait. Once the energy in the can is reduced, the shock waves stop and the agitated bubbles stop moving around in the can, you’re good to open the can.
Why did researchers use Carlsberg beer for this scientific experiment?
Shockingly the answer isn’t, “because it was the easiest beer to find.” It turns out Carlsberg is one of Denmark’s largest and most popular breweries, AND it was founded in there nearly 175 years ago! So…maybe the answer actually was, “it was the easiest beer to find—in Denmark!”
So you’re a bit of a stickler for science eh? You may also like…
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