How to choose · 5 min · 17 September 2026
Glass or PET: taste, storage and shelf life
How water in glass differs from PET and when it actually matters.
In short: the water is the same either way, the difference is in how the packaging holds gas and odours. Glass is more neutral and better for serving, PET is lighter and cheaper to deliver.
Why does water in glass seem to taste better?
Glass lets no gas through and gives off no odours, so the water inside stays closer to how it left the bottling line. PET does let gas through, slowly, but noticeably by the end of the shelf life, especially with a naturally carbonated water like Narzan, where free CO₂ runs at about 2.5 g/l. The composition itself does not change with the packaging: calcium, magnesium and mineralisation are identical in glass and in plastic.
- Glass gives off no odours and holds the carbonation longer
- PET lets gas through slowly, but noticeably by the end of the shelf life
- Close an opened bottle tightly and put it in the fridge
Storage and shelf life
What harms water is sun and heat, not the packaging. On Phuket a pack left on the balcony or in a car boot heats up within minutes, and the taste is ruined long before the date on the label. Check the shelf life on that label: glass usually gets 12 months, PET less. Close an opened bottle tightly and put it in the fridge, where sparkling water holds its taste for a day or two before the bubbles are largely gone.
- Direct sun and heat are what harm the water
- Shelf life is on the label: usually 12 months for glass and less for PET
- On Phuket, do not keep water on the balcony
In practice: what to buy
It is easier to choose by the occasion than to argue about taste. At home and in the office, volume is the cheapest route: 18.9 l bottles for a pump or cooler, plus a case of mineral water in 0.45 l glass for the table. In a restaurant, 0.45–0.5 l glass goes on the table. For the banya, the gym and the yacht, take PET: it is lighter, it does not break, and you will not mind burying it in ice. With us, 0.5 l PET means still water, while Narzan and Essentuki No. 4 come in 0.45 l glass only. Bottles carry no deposit, while the 18.9 l ones are returnable: we collect the empty with your next delivery.
- Home and office: 18.9 l bottles, plus a case of 0.45 l glass for the table
- Restaurant and serving guests: glass
- Banya, sport and yacht: still water in 0.5 l PET, lighter and unbreakable