Stainless steel is an iron-chromium alloy that does not rust, leach or absorb flavours. It is used for reusable bottles, cups, straws, cutlery and lunchboxes, and for returnable containers in reuse schemes.
It replaces single-use PET bottles, plastic and paper-lined cups, plastic straws and disposable food containers, and outlasts plastic reusables.
Steel takes a lot of energy to make, so a steel cup needs about 130 uses to beat a paper coffee cup on climate, in a study paid for by the paper-cup makers Huhtamaki and Stora Enso and summarised by the United Nations Environment Programme (UNEP). The 2025 Environmental Research refill study shows a reusable bottle used daily for a year has negligible impact compared with 730 single-use PET bottles (two half-litre bottles a day). A 2023 Belgian study of straws found per- and polyfluoroalkyl substances (PFAS) in 90 percent of paper brands, most bamboo and plastic straws, and some glass straws, and none in stainless steel.
Drawbacks: high upfront cost and energy to produce; heavy; needs many uses to pay back; if bought and abandoned it is worse than the plastic it replaced. Fully recyclable at end of life.