Material

Silicone, platinum cured

Family: Silicone

What it is

Platinum-cured silicone is silicone rubber set with a platinum catalyst instead of a peroxide, the material of many lid gaskets and seals. The cure matters because, according to silicone maker Wacker, curing this way forms no peroxide breakdown products.

Why it matters in your kitchen

The gasket in a storage lid or bottle cap sits against your food every time it tips. It's often the only part that isn't metal or glass.

Silicone makers sell food-contact grades meant to meet FDA's rule for rubber articles (21 CFR 177.2600) and Germany's BfR recommendation on silicones, once properly cured and post-cured. A maker that names the cure and the standard is telling you something specific.

It's still a polymer. A container with a silicone gasket isn't plastic-free in the strict sense, and our profiles say so.

Good at

Sealing. It flexes into a lid groove and springs back, so lids close tight.
Heat. Wacker recommends heat stabilizers only above about 180°C (356°F), well above a dishwasher cycle or a hot soup.
Replaceable. Many makers sell spare gaskets, so a worn seal doesn't mean a new container.

Watch for

Gaskets trap water. Take the gasket out to wash it, as OXO tells you to for its containers, and let it dry before you put it back.
It wears. Replace a gasket that's torn, cracked or no longer seals.
"Platinum cured" needs paperwork. Ask the maker which food-contact standard the part meets.
It isn't plastic-free. If you want no polymers at all, look for metal or glass lids with no seal.

Who it suits

Good for you if you want lids that seal and a maker who documents the cure and standard. Skip it only if you want containers with no polymer parts at all.

In short. Platinum-cured silicone is a flexible food-contact rubber cured without peroxide by-products, and it's still a polymer that wears and gets replaced.

When a maker says only "silicone," see silicone, cure not stated. For what research has and hasn't shown about kitchen materials, see our guide.

Where it is used

Lid gaskets on containers and bottles
Seals in presses and brewers

How to care for it

Remove gaskets to wash them, and let them dry before reassembling.
Replace a gasket that's torn, cracked or no longer seals.

What the label tells you

It's platinum cured, and the specific FDA or BfR statement, when the maker documents them.

What it doesn't tell you

Silicone is a polymer. A product with a silicone gasket isn't plastic-free in the strict sense, and the profile says so.
It doesn't support health promises.

Material pages describe the material in general. The profile on each product page says what we know about that product and how we know it.