The cap is steel too
This is the fact worth knowing, and almost nobody in the category can say it.
Hydro Flask, in their own FAQ: “All of Hydro Flask’s caps are made out of BPA/BPS free polypropylene.” Chilly’s, Stanley, Mepal, Dopper — polypropylene. Even Klean Kanteen, the most credible name in the category, ships a polypropylene cap as standard and charges extra for one that isn’t.
Ours is steel, as standard. See the whole category, cap by cap.
Every surface your water touches is 304
The inner wall and the inside of the cap are 304 food-grade stainless steel, with one food-grade silicone ring so the cap seals. No coatings, no inner liner, nothing between the steel and your water.
The outer wall is a second grade of steel, 201, which never touches your water. We name it, because leaving it out would be exactly the kind of rounding-down this page is about.
The same clean taste on day one and day one thousand
Steel is non-porous. It doesn’t hold on to yesterday’s coffee, or last week’s squash, or the faint plastic note that a well-used bottle eventually develops. Water tastes like water.
The ring is removable, so you can actually clean the one part that traps things.
Built to be kept
Ten years on the steel — rust included, not quietly excluded in the small print. The silicone ring is the only part that wears out, and we sell you a new one for a few euros, for as long as you own the bottle.
That is what a ten-year product actually looks like: not a warranty page, but a spare part you can buy.
And what it won’t do
You can’t see how much is left. It’s heavier than plastic. It is double-walled but not vacuum-insulated, so it will not keep coffee hot. If any of those matter more to you than what your water touches, buy something else — with our blessing.
