Insulated Steel Water Bottle

Details

A double-wall vacuum bottle in 304 stainless steel, the same grade inside and out. Stainless steel is not a claim. It is a family, and the difference between two members of it is the whole product. SS 304 runs about 18 percent chromium and 8 percent nickel. SS 202 runs about 17 percent chromium and only 4 percent nickel, with manganese standing in for the nickel it is missing, and that substitution is why 202 pits and rusts at the base ring inside one monsoon. A very common build is 304 for the inner wall, which the marketing photographs, and 202 for the outer, which nobody sees until it stains. Both walls here are 304, and the grade is confirmed by X-ray fluorescence on a sample from each production lot, not asserted on a sticker. If a shopkeeper offers a magnet as proof, it proves nothing: both grades are austenitic and both go slightly magnetic after cold forming. The retention figures are the other soft number. Twenty-four hours cold means nothing without a fill temperature and an ambient temperature, and almost nobody prints either. Ours are measured by the EN 12546-1 method: filled to capacity, cap closed, held in still air at 20 degrees, with the water temperature logged at intervals. Hot figures start from a 95 degree fill and are quoted to the point the water drops below 60 degrees. Cold figures start from a 5 degree fill with no ice and are quoted to the point it passes 10 degrees. The lid is the part that fails, and it fails at a gasket.

• Both walls SS 304, confirmed by XRF per lot, no 202 anywhere
• Double wall vacuum, base port welded and copper shielded
• Retention measured to EN 12546-1: 95 degree fill, 20 degree still air, logged
• Lift-out food-grade silicone gasket, free replacements for five years
• Wide 53 mm mouth, takes ice cubes and a bottle brush
• Powder-coated grip finish over bare steel, no plastic sleeve
• Interior is bare unpainted steel, no liner and no coating
• Heavy metal migration tested at a NABL-accredited materials laboratory
• No 201 or 202 steel, no plastic liner, no painted interior
• Not dishwasher safe and not for carbonated drinks. A dishwasher cycle drives water into the base port seal, and carbonation pressurises a sealed vacuum body.