Not every Stainless Steel bottle is 304
304 is the food-grade standard. Here's how to tell if yours actually is one — and what happens if it isn't.
What it means for daily use
- Reacts with what you drinkLemon water, coffee with milk, electrolyte drinks speed up corrosion.
- Struggles with humidityA quick rinse instead of full drying corrodes it faster.
- Scratches become weak pointsKeys, drops, rough sponges — corrosion starts right there.
- A false economyCheaper upfront, degrades faster, replaced sooner.
What it means for daily use
- Built for what you drinkResists corrosion from lemon water, coffee, electrolyte drinks.
- Handles humidity properlyHigher chromium forms a protective layer that lasts.
- Holds up to everyday wearScratches and drops don't become corrosion points.
- A recognized food-contact standardUsed across the global food & beverage industry.
We tested our own bottles. Here's the result, on camera.
Stainless steel test liquid reacts differently depending on the grade of metal it touches. The further left, the lower the grade.
Lowest grade tested — strongest reaction, deepest red.
Still a strong red-brown reaction — the grade behind most cheap "stainless steel" bottles.
Reaction lightens slightly, but still clearly reactive.
A muted rose-grey — closer to food-grade, but not quite there.
Turns green, not red — the signal for genuine food-grade 304.
Before you trust any bottle, check it yourself.
Magnet test
Genuine 304 and 316 are non-magnetic or only very weakly magnetic. A strong pull usually means 201 or an iron blend.
Smell test
Wet the surface and smell it. Lower grades tend to give off a noticeably metallic smell — genuine 304 shouldn't have one.
Sanity-check the price
Food-grade 304 costs meaningfully more to produce than 201. A price far below market for the same size and features is worth questioning.
Every Mizzu bottle is 304. Proven on camera, not on paper.
We filmed the same tests anyone can run — on our own bottles, in front of a camera — and we stand behind the result.
