Steel, but better.
First, what even is steel?
Steel starts as iron. On its own, iron is soft and it rusts. Add a little carbon and you get steel — harder and stronger, the metal in everything from bridges to knives.
But plain steel — carbon steel — still rusts. Leave it damp and it slowly turns to flaky orange iron oxide.
Stainless steel is steel with one more ingredient: chromium. Add at least 10.5% chromium and the steel stops rusting. That's the whole difference — carbon steel is strong but hungry for rust; stainless is steel that protects itself.
Why chromium stops rust.
Rust isn't dirt sitting on the surface — it's the iron itself turning to oxide, and once it starts it keeps eating inward, flaking as it goes.
Chromium plays a cleverer trick. It grabs oxygen first and forms a layer of chromium oxide just a few atoms thick — invisible, bonded tight to the metal, sealing the iron away from air and water. This is the passive film.
And it's self-healing: scratch it, and the freshly exposed chromium grabs more oxygen and reforms the layer within hours. The steel repairs its own skin. That's why stainless stays bright for decades — and why it doesn't react with your food.
The recipe.
For food-grade stainless steel — the 304 grade we use — the recipe is:
| Element | Percentage | Why it's there |
|---|---|---|
| Iron (Fe) | ~70% | The base metal. Structure and strength. |
| Chromium (Cr) | 18% | Creates the passive film that prevents rust. |
| Nickel (Ni) | 8% | Changes the steel's structure — tougher, more formable, more acid-resistant. |
| Carbon (C) | <0.08% | Adds hardness. Kept low to prevent carbide formation. |
| Manganese (Mn) | ~2% | Improves strength and aids manufacturing. |
This is why 304 is also called 18/8 — 18% chromium, 8% nickel.
And the nickel? What the '8' brings to the steel.
If chromium is what stops the rust, nickel is what makes the steel *behave*. Adding nickel changes the steel's internal structure — into what metallurgists call austenite — and that's what makes 304 tougher, easy to press into a seamless shape without cracking, and even more resistant to acids. It's the reason 304 shrugs off tomato sauce, the freezer and the dishwasher where a cheaper steel would pit or stain.
Nickel is also the most common metal allergy — roughly 1 in 7 women and 1 in 50 men react to it, usually from cheap jewellery pressed against skin for hours. So it's fair to ask whether a steel container leaches enough to matter. For everyday use, no: an allergy is a skin-contact reaction with a threshold, and good stainless releases far too little to cross it. The trace that does reach food is the same nickel already in spinach, nuts and chocolate — in smaller amounts (more on our Food Safety page).
For the few people who are highly sensitive, nickel-free steels do exist — 18/0 (grade 430: 18% chromium, zero nickel — the 'stainless' in a lot of cutlery) and high-nitrogen medical grades used for implants. They trade a little corrosion resistance for no nickel. We use 18/8 because, for food that gets frozen, reheated, made acidic and dishwashed, its all-round corrosion resistance is the safest choice.
From raw material to finished product.
1. Melting
Raw materials melted in an electric arc furnace at ~1,500°C. Refined to exact 304 composition.
2. Hot Rolling
Molten steel cast into slabs, then rolled at high temperature into thinner sheets while still red-hot.
3. Cold Rolling
Rolled again at room temperature. Gives the smooth, brushed finish.
4. Stamping
Flat sheets pressed into shape using a die. Our containers are deep-drawn from a single sheet — no welding, no joints.
5. Finishing
Trimmed, polished, inspected. Lid made separately, sized to friction-fit onto the container rim.
Why single-piece construction matters: No welds means no weak points. No joints means no crevices where bacteria can hide. One sheet of steel, one continuous surface.
A century of proof.
- Hospitals use it for surgical instruments — it can be sterilised repeatedly without degrading
- Commercial kitchens use it for every surface — hygienic and withstands constant use
- Breweries and dairies use it for tanks and pipes — doesn't react with acidic or alkaline liquids
- Your home probably already has it — pans, cutlery, sinks, kettles
It's not new technology. It's proven technology that, until now, wasn't applied to food storage with the same rigour.