Short answer: a solid (unlined) copper bottle is copper all the way through, so the water touches copper. A lined bottle has copper on the outside and a different material on the inside — usually stainless steel, sometimes a lacquer or plastic coating — so the water never touches copper. A copper-plated bottle is usually stainless steel with a thin copper-coloured layer on the outside only.
The three types, side by side
| Solid / unlined copper | Copper-lined (double-wall) | Copper-plated | |
|---|---|---|---|
| What touches the water | Copper | Stainless steel or a coating | Stainless steel |
| Inside colour (look with a torch) | Copper | Silver or coated | Silver |
| Hot drinks | No | Usually yes | Usually yes |
| Lemon, juice, acidic drinks | No | Usually yes | Usually yes |
| Dishwasher | No | Check the maker | Check the maker |
| Ageing | Darkens and develops a patina | Outside may darken | Plating can wear or scratch |
Which one should you choose?
- Choose solid copper if you want the traditional Ayurvedic practice of keeping plain water in a copper vessel (called tamra jal). That tradition depends on the water touching copper.
- Choose lined or plated if you want the copper look but need a bottle for coffee, tea, sports drinks or juice.
How to tell what you are buying
- Look inside. Shine a torch into the neck. Solid copper is copper-coloured inside. Silver means stainless steel.
- Read the listing carefully. "Copper finish", "copper-coated" and "copper-plated" usually mean the copper is only on the outside.
- Check the care rules. A seller who says "water only, no hot or acidic drinks" is usually selling unlined copper. A seller who says "hot or cold, any drink" is usually selling a lined bottle.
What the Tamra bottle is
The Tamra bottle is solid, unlined, 99.9% pure copper with a hand-hammered finish and a threaded cap with a food-safe silicone seal. There is no lining, lacquer or plastic inside. It comes in 500ml, 750ml and 1L, and it is made for cool or room-temperature plain water only.
We describe Ayurvedic use as a cultural tradition. We make no health or medical claims about copper or about water stored in copper.