Guides
What is tri-ply cookware?
The short answer: tri-ply cookware is three layers of metal bonded together, a heat-spreading aluminium core sandwiched between two layers of stainless steel. The best kind is full-clad, where those three layers run from the centre of the base right up the sides, so the whole pan heats evenly rather than just the bottom.
The three layers, and what each one does
| Layer | Usual metal | Its job |
|---|---|---|
| Inside (cooking surface) | 18/10 stainless steel | Tough, non-reactive, fine with acidic food like tomatoes and wine, happy with metal utensils |
| Core | Aluminium | Spreads heat quickly and evenly across the pan |
| Outside | Magnetic stainless steel, often 430 grade | A durable outer shell that also works on induction hobs |
18/10 refers to the chromium and nickel in the steel, roughly 18% and 10%. Chromium resists rust; nickel adds shine and corrosion resistance. 430 steel has little or no nickel, which is what makes it magnetic.
Why an aluminium core?
Stainless steel on its own is a poor conductor of heat. A pan made only of stainless steel heats in a ring above the flame or element and stays cooler everywhere else, so food scorches in one spot while it barely cooks in another. Aluminium conducts heat many times better than stainless steel and is light, so a thin core carries heat sideways across the base before it reaches the food. You get the even heat of aluminium with the hard-wearing, easy-to-clean surface of stainless steel. Some pans use a copper core instead; it conducts even better but adds weight and cost.
Full-clad or disc base: the difference that matters
There are two ways to put an aluminium core into a stainless pan.
- Disc base (encapsulated base): a thick aluminium disc is fixed to the underside of a single-layer stainless pan. The base heats well, but the sides are thin stainless steel only. Heat stops at the edge of the disc, so sauces catch where the base meets the wall, and food at the edges of a frying pan cooks more slowly.
- Full-clad: the three layers are bonded together as one sheet before the pan is shaped, so the core runs all the way up the sides. Heat is even from the centre to the rim. This is what serious cooks look for, particularly in frying pans and saucepans, where heat up the sides changes how food cooks.
An easy way to tell them apart: look at the rim. On a full-clad pan you can often see the layered edge. A disc-base pan usually has a visibly thicker, separate disc on the bottom with a step where it joins the wall.
What to look for when buying tri-ply
Full-clad construction, with the core running up the sides.
18/10 stainless steel inside for the cooking surface.
A magnetic outer layer if you have, or might one day have, an induction hob.
A stated oven-safe temperature for both pan and lid, so you can finish dishes in the oven.
Sensible weight: thick enough to sear without hot spots, light enough to toss with one hand. Tri-ply is far lighter than cast iron.
Firmly riveted handles and a flat base that will not rock on a ceramic or induction hob.
Dishwasher safe, if that matters to you. Bare stainless has no coating to protect.
How tri-ply cooks
Tri-ply is the pan for browning: steaks, chicken thighs, scallops, onions, and the brown bits left behind that become a pan sauce. It has no non-stick coating, so it lasts decades rather than a couple of years, but it asks for one bit of technique. Preheat the empty pan over a medium heat for two or three minutes, add oil, then add the food and leave it alone until it releases. Food sticks when it goes into a cold pan or gets moved too early. Learn that and you can cook almost anything in it, eggs included.
The Season Tri-Ply range
Season Tri-Ply is full-clad: stainless steel bonded around an aluminium core that runs up the sides, so heat spreads evenly and nothing catches at the edges. It has 18/10 stainless steel inside and 430 steel outside, works on all hobs including induction, is dishwasher safe and has a 10 year warranty.
- Season Tri-Ply Stainless Steel Frying Pan, £50 to £75, in 22cm, 26cm, 28cm and 30cm. Oven safe to 240°C. The 26cm weighs 775g.
- Season Tri-Ply Stainless Steel Saucepan, £60 to £70, in 16cm (1L), 18cm (1.5L) and 20cm (2L). Oven safe to 240°C, lid to 180°C.
- Season Tri-Ply 2 Piece Frying Pan Set, £90, a 22cm and a 28cm pan.
Where to go next
Weighing up stainless against a coated pan? Read stainless steel or non-stick frying pan. Choosing sizes: what size frying pan do I need? and which saucepans do I actually need? Then put it to work with how to make a pan sauce.
Questions people ask
Is tri-ply the same as stainless steel? Tri-ply is stainless steel on the inside and outside with aluminium in between. A single-layer stainless pan heats far less evenly.
Does tri-ply work on induction? It does when the outer layer is magnetic stainless steel, such as 430 grade. A fridge magnet that sticks firmly to the base is the quick test. More in do stainless steel pans work on induction?
Can tri-ply go in the oven? Usually, yes, but check the stated limit for pan and lid. Season Tri-Ply pans are oven safe to 240°C, saucepan lids to 180°C.
Is tri-ply better than five-ply? Not automatically. Extra layers add weight and slow the pan's response. Well-made full-clad tri-ply heats evenly and responds quickly, which is what most cooks need.
Why does food stick to tri-ply? Usually the pan was not hot enough, or the food was moved too soon. Preheat, add oil, and wait for it to release.
Cook it with
Cook like it matters.
From the cooks at Season, a London cookshop since 2005.