Stainless steel starts with a metallic taste, but after first week of use it is usually gone. Also there is titanium and aluminium.
Or just get a reusable plastic one, perfect can be an enemy of good.
Individual use of plastic is not relevant, as long as it goes to landfil and not ends up in the ocean througg recycling fraud. In UK most plastic ends up sent to poland, where it's burnt or sent onwards to Turkey where it becomes untraceable. I stopped recycling plastic because the system cannot be trusted - at least if it stays in UK you know it wont be hurting anyone.
Half of plastic waste in the ocean waste is discarded fishing nets.
I once did a fair amount of experimentation and found titanium to impart a much stronger metallic taste than stainless steel.
Aluminum is not an amazing food contact surface — it’s quite reactive. I would not use an uncoated aluminum bottle for anything other than plain water.
If you’re sensitive to metallic residual taste, then look for containers made from a type of stainless that meets your needs. There are many kinds [1], I prefer 316 but you might need 321 for example. Some day I’ll engage a machinist to fab one up for me that uses standard gaskets I can get from any MRO firm in the world.
Glass with a silicone sleeve over it is surprisingly resilient. I have had a few glass bottles with silicone covers that I carry around (not all at once...) and have dropped them more times than I can recall and they always just bounce. Of course they can break, especially if you do something like put it in your shopping cart and drop something heavy on it (whoops).
The inertness of glass not only makes it always the first choice for food contact, it's also the most cleanly recycled material on the planet, when it does break. Unlike plastics (which for all practical purposes can't really be recycled), and metals, which require complex separation and realloying, glass can be easily separated visually and reused indefinitely. It is quite likely that the glass in your refrigerator right now contains glass first produced by the Romans.
(Of course, we should just reuse glass containers, like we did when I was a kid - a small deposit is a big motivator for kids to collect bottles for reuse!)
More than steel? We're talking about reusable bottles here, shipped empty. What is the comparison of empty glass or steel to full plastic? What is the difference in mass?
There exist industrial reaction vessels etc which are made of stainless steel with a bonded liner made of glass. That seems like the ideal "forever" food container material to me - chemically nonreactive and easy to clean, but lightweight and resilient to impact. The glass layer would be lost in recycling, but it shouldn't impede recycling the metal too badly as it'd just be a tiny bit more slag in the crucible.
Some also come with a non-stick (Teflon-type) coating. Zojirushi makes incredibly nice vacuum-insulated bottle [1] that unfortunately has a non-stick liner. The inside of the bottle is super easy to clean, but the chemicals used in the manufacturing are awful.
In theory the liner is PTFE (or maybe a different fluoropolymer) with nothing left to leach out. PTFE and its relatives are stable to temperatures well above that of boiling water, so leaching shouldn’t be an issue.
(One big problem with PTFE is that it starts to slowly decompose at a lower temperature than its melting point. This makes it messy to work with. As I understand it, the decomposition products are gasses, so this is a problem at the factory and for the environment, but I don’t think its a problem for end users.)
