“How to Keep Your Soft Drink Bubbly: Tips from an Engineer-Brewer”

“There are three types of gases in the food industry,” says engineer-brewer Jean-Claude Claeys of the international gases company Messer. He is responsible for research and development, among other things, and supports various countries in everything related to the food industry.

“Liquid nitrogen or carbon dioxide (CO2) can serve as a means of freezing something without drying it out, preserving the quality and freshness of the product. In addition, CO2 can be an additive that the food industry uses to pack a packet of salami or a bag of lettuce to keep it longer, because CO2 inhibits the growth of micro-organisms. Finally, a gas can also be an ingredient when it enters your body as part of a product.”

“The gas in your drinks is CO2 or carbon dioxide: a light acid with a specific smell. In contrast to argon, oxygen and nitrogen, CO2 dissolves very easily in water. Especially at cold temperatures. At 50°C it is much more difficult to dissolve carbon dioxide in water than at 0°C. At a low temperature, CO2 stays in the bottle longer, but you have no control over that yourself.”

“The CO2 in your soft drink bottle always seeks a balance in pressure and concentration, for example three bar pressure and eight grams of CO2 per liter of water. For soft drinks, the CO2 content varies between four and ten grams per litre. When the bottle is only half full, the CO2 that is still in the liquid will again seek equilibrium in the vacated space above the liquid. Before that, the gas will come out of the liquid, leaving you with fewer bubbles in your drink. That eventually leads to the hissing sound when you unscrew the cap.”

“Here’s the very best tip: drink your bottle quickly,” laughs Claeys. “Smaller bottles can also help. Close your bottle properly, otherwise the CO2 will continue to be released from the drink. You can also squeeze a plastic bottle to make the free space smaller. If you close the bottle again properly, you will keep bubbles longer. If you manage to squeeze the bottle so that your liquid comes up to the cap, there will be a smaller vacated space and the CO2 will balance much faster. Less CO2 must then migrate from your drink. You could notice that difference.”

You may have heard that it helps to put a spoon in an open bottle of champagne, with the handle down. Something you may have already tried for soft drinks. “But it is a myth that this keeps the injection longer. Rather just put the stopper on the bottle,” says the expert. “You will also not notice any difference if you keep your drink cold without a stopper. It may be tastier, but the CO2 will still seek that balance. Laying the bottle flat or upside down is also pointless. In addition, do not shake the bottle. And by pulling air out of the bottle with a vacuum pump – as you do with wine – you get the opposite of what you want, because that’s how you pull the CO2 out of your bottle.”

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