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Friday 19th September 2014
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Does tightening cola bottle lid help keep it fizzy?

Question

fizzy-water.jpgDoes screwing the top of a bottle of fizzy drink really tight stop it from going flat?
Paul, The City

Answer

** Definitive **
Name: Professor Hal
Qualification: Mystery Hour’s fizziest correspondent
Answer: There is actually quite a lot of technology in a cola bottle. In the thread under the lid, there are straight grooves at right-angles to the thread. These are there as a safety measure as when the bottles first came out, people would open them and just as people would open them, the pressure would force the lid off and into their eye. Those grooves line up with the grooves in the lid and that’s why you get that satisfying hiss which lets bits of the gas out, getting rid of the lion’s share of the pressure. If you don’t do the bottle up tight enough, perhaps the grooves will line up and you will lose some pressure and some fizz.

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