Aluminum and tinplate (tin-plated steel) are the two metals behind most rigid metal packaging. Aluminum is light and highly formable, so it is the usual choice for beverage cans, monobloc aerosols and tubes. Tinplate is thin steel coated with tin; it is stiffer and stronger, and it is the standard for food cans, paint and chemical cans, and many aerosol cans.
Both metals are complete barriers to light, oxygen and moisture. Both are recycled at high rates. And both rely on an internal coating to keep the metal from reacting with the product inside.
Aluminum vs. tinplate at a glance
| Property | Aluminum | Tinplate (tin-plated steel) |
|---|---|---|
| What it is | Aluminum alloy sheet or foil | Low-carbon steel sheet with a thin tin coating |
| Weight | About one-third the density of steel | Heavier |
| Strength and stiffness | Lower; relies on can shape and pressure for rigidity | Higher at a given thickness |
| Barrier | Full barrier to light, oxygen and moisture | Full barrier to light, oxygen and moisture |
| Corrosion | Corroded by acidic or salty products if unprotected | Steel rusts where the tin and coating are breached |
| Internal coating | Required for most food and beverage contents | Required for most food contents |
| Sorting for recycling | Eddy-current separation | Magnetic separation |
| Typical uses | Beverage cans, monobloc aerosols, tubes, foil, trays | Food cans, paint and chemical cans, aerosols, ends, closures |
What is tinplate?
Tinplate is low-carbon steel sheet with a thin layer of tin applied to both sides, usually by electroplating. The tin protects the steel from rust and gives a surface that takes lacquer and print well. Tinplate also welds well, which is why it is the material for three-piece welded cans.
A related material, tin-free steel (ECCS), uses a chromium coating instead of tin and is common for ends and closures. The name “tin can” is historical: a tinplate can is almost entirely steel.
Which is lighter, and which is stronger?
Aluminum is about one-third the density of steel. That makes aluminum containers lighter to ship and easier to form into seamless shapes, such as two-piece beverage cans and monobloc aerosols.
Steel is stiffer and stronger at a given thickness. That suits food cans that go through retort sterilization, sit under vacuum, and are stacked high in warehouses.
Do aluminum and tinplate cans corrode?
Both can, which is why most food and beverage cans in either metal are coated inside.
- Aluminum: beer and other acidic beverages corrode unprotected aluminum, so aluminum beverage cans carry a thin polymer liner that keeps the drink off the metal (Sheehan, Sacks et al.).
- Tinplate: the tin layer protects the steel, but the contents can still attack the container. Corrosion is a particular problem with highly acidic or high-salt products, and it can contaminate what is inside (US patent background).
Which is more recyclable, aluminum or tinplate?
Both metals can be recycled repeatedly without losing their material properties, and both are recycled at high rates in Europe.
- Steel: 80.5% of steel packaging placed on the EU market was actually recycled in 2022, according to independently verified figures (Steel for Packaging Europe, via Packaging Insights).
- Aluminum: the recycling rate for aluminum beverage cans across the EU, UK, Switzerland, Norway and Iceland reached 76% in 2021 (Metal Packaging Europe and European Aluminium, via Packaging Europe).
The two figures cover different years, scopes and packaging types, so they should not be read as a ranking.
Steel’s magnetism is a practical advantage at the sorting stage. Introducing ferromagnetic sorting at waste facilities helped Poland raise its steel packaging recycling rate by 20% in one year (CanTech International).
Which costs less, aluminum or tinplate?
There is no universal answer.
- Metal prices per tonne move with commodity markets, energy costs and trade measures. The EU has finalized anti-dumping duties on Chinese tinplate, and Malaysia has imposed provisional duties on tinplate imports from four countries (Mysteel).
- Because aluminum is lighter, a container uses less weight of metal.
The useful comparison is cost per finished container, for a specific format, in a specific region.
Where is each metal used?
Aluminum: beverage cans, monobloc aerosol cans, collapsible tubes for cosmetics and pharmaceuticals, foil, food trays.
Tinplate: three-piece welded and two-piece food cans, paint and chemical cans, three-piece aerosol cans, can ends, closures and crowns.
What do both metals need to get right?
Whichever metal is used, the internal coating does most of the work of protecting the product. One can supplier identifies correct application of the internal coating, meaning its thickness and uniformity, as the most critical factor in can corrosion, and notes it can vary widely even within one pallet (American Canning, via Beer & Brewing).
That makes coating checks a routine part of canmaking: on flat sheet before forming, on finished cans and tubes, and along the welded side seam of three-piece cans. Innosen builds equipment for each stage:
- the CoatPro™ IS860 coating thickness gauge with the Hoverprobe® II IS9651 and Tube Probe IS9561 for coating thickness
- the EnamelPro™ IS810 enamel rating gauge for metal exposure through the internal coating of cans and ends
- the IS670 Missing Side Seam Lacquer Detector for three-piece welded can bodies
See the full range on the Products for Quality Assurance page. For more on what goes wrong when the coating fails, read our guide to metal can defects and enamel rating failure mode and effect analysis.
Frequently asked questions
Is a tin can made of tin?
No. A “tin can” is made of tinplate, which is steel with a very thin tin coating. Most of its weight is steel. Many beverage cans are aluminum and contain no tin at all.
Why are most beverage cans made of aluminum?
Aluminum is light and can be formed into a seamless two-piece can. It is also widely recycled; in Europe the beverage can recycling rate reached 76% in 2021.
Do aluminum cans rust?
Rust is iron oxide, so aluminum does not rust, but it does corrode when acidic or salty contents reach bare metal. Tinplate steel can rust where the tin layer and coating are damaged.
Which is more recyclable, aluminum or steel?
Both can be recycled repeatedly. In the EU, 80.5% of steel packaging was recycled in 2022. Steel is also easy to separate from other waste with magnets.
Do aluminum and tinplate cans have a lining?
Most food and beverage cans in both metals have an internal coating, often called a lacquer or liner. It keeps the product from touching the metal and protects against corrosion over the product’s shelf life.
Sources
- Steel for Packaging Europe: 80.5% steel packaging recycling rate for 2022
- Metal Packaging Europe and European Aluminium: 76% aluminum beverage can recycling rate for 2021
- Sheehan, Sacks et al., Lactic and Acetic Acids in Sour Beers Promote Corrosion During Aluminum Beverage Can Storage
- worldsteel: Steel Packaging
Related products: CoatPro™ IS860 · Hoverprobe® II IS9651 · Tube Probe IS9561 · EnamelPro™ IS810 · IS670
