Bloom Steel Straw Cup

Details

The cup after the sipper, from around nine months, when a baby can draw on a straw. Vacuum-walled steel, because this is the year everything gets thrown off a high chair. Stainless steel is not a claim. There are hundreds of stainless steels and the one that matters here is AISI 304, designated X04Cr19Ni9, about 18 percent chromium and 8 percent nickel, to IS 5522 for sheet used in utensils. What is widely substituted across Indian steelware is 200-series steel, usually called 202, which cuts the nickel to under 4 percent and replaces it with 7 to 9 percent manganese. It costs less, it pits and corrodes far sooner, and it releases more metal into an acidic drink. Every lot here is checked by XRF and reads 18.2 percent chromium and 8.4 percent nickel. One correction worth having, because it circulates constantly: a magnet does not tell 304 from 202. Both are austenitic and both are close to non-magnetic. A magnet distinguishes them from 430, which is a different question. The only honest test is composition, which is why the figures above exist. The part nobody discusses is the straw. A straw cup is the one piece of feeding equipment that reliably goes bad, and it goes bad in three places: inside the straw, in the groove the lid gasket sits in, and in a bite valve. This cup has no bite valve. The gasket lifts out of its groove with a fingernail. The straw pulls out whole and the 5 mm brush in the box passes through its 6 mm bore, which is the only way to know the inside is clean. And the rule nobody prints: water can sit in a straw cup, milk and juice cannot. Milk residue in a 6 mm silicone tube at Indian room temperature is why a straw cup starts to smell, and no rinse reaches it.

• AISI 304 food-grade stainless, 18.2 percent chromium and 8.4 percent nickel by XRF, to IS 5522. Unpainted inside
• Nickel release below 0.14 mg per kg and chromium below 0.25 mg per kg into 0.5 percent citric acid, 2 hours at 70 C
• Vacuum wall: filled at 5 C in a 25 C room, it passes 15 C at about 8 hours. That is the protocol behind the number
• Silicone straw, 6 mm bore, weighted stainless end so it still draws when the cup is tilted. 5 mm cleaning brush and one spare straw in the box
• Flip lid with a lock, silicone gasket that lifts out, strap loop. Lid in polypropylene to IS 10910
• Outside is a powder coat, lead and cadmium below the limit of quantification, cross-hatch adhesion 5B to ASTM D3359
• 300 ml to the fill line, 340 ml to the brim, 280 g empty
• Drop tested 100 times from 1 metre onto tile
• Never steam sterilise or boil the insulated body. Heat destroys the vacuum and you get an ordinary steel cup. Lid and straw are fine in either
• Honest trade-off: steel is heavy, it dents, and a dented vacuum wall is a dead vacuum wall. It will be thrown, so expect marks. The steel does not stop being safe when it is dented, it just stops being pretty
• Honest trade-off, second: an insulated cup cannot go through a steriliser, so from nine months onward you are washing rather than sterilising. That is the ordinary advice at this age anyway
• Not for hot drinks and not for carbonated drinks. Replace the straw every 3 months, or when it is chewed through