Have you ever wondered why water bottles often have an expiration date – whether it's still or sparkling water? Does that mean bottled water can actually go bad?
"No," says Hannah Zeyssig, a consumer protection advocate in Germany specialising in sustainable food production. If you see this label, then it's likely because it's legally required in your country by laws mandating a best-before date.
In the US, the Food and Drug Administration (FDA) does not require an expiration date for bottled water, since it has determined these products have an indefinite shelf life.
However, required or not, many manufacturers will still set the best-before date at around two years. "This mainly concerns taste and perception, not safety," Zeyssig says. In fact, water is still drinkable many months after the expiration date – provided it is stored in a cool, dark, and dry place.
As long as the bottle remains unopened, no microorganisms are activated. However, improper storage, such as exposure to heat and sunlight, can lead to changes in taste.
"It almost never becomes 'bad' in a health sense," Zeyssig explains. "But it can become 'unpalatable' in terms of taste."
Sparkling water often lasts longer than still water due to the carbon dioxide, which inhibits microbial growth. Glass bottles are also advantageous, according to the expert, as they reliably protect against flavour loss.
PET bottles, on the other hand, are less airtight. Carbon dioxide can escape, and if exposed to heat, acetaldehyde can leach from the bottle into the water. This colourless chemical compound is harmless, but can negatively impact the taste of the water. – dpa
