Borosilicate Glass Storage Jars

Details

Glass for the things you want to see: achar, pulses, ghee, leftovers. The body is borosilicate 3.3 to ISO 3585 and ASTM E438 Type I Class A, 2.8 mm wall, and the lid is SS 304 with a food-grade silicone gasket rather than plastic. The 3.3 in the name is not branding, it is the coefficient of linear thermal expansion, 3.3 millionths per kelvin. Soda-lime, which is what an ordinary jar is made of, runs about 9. That single number is the whole difference: it is why borosilicate takes a step of about 150 K and soda-lime cracks at roughly 40, and it is why one goes from the fridge into a warm oven and the other does not. Borosilicate is also the most routinely misdeclared material in an Indian kitchen shop, because the two look identical and the label costs nothing. There is a check and it needs only a kitchen scale, because the two glasses differ in density as well: borosilicate is 2.23 grams per cubic centimetre and soda-lime is 2.50, about 12 percent heavier for the same shape. So the weights are published here, and a jar of these dimensions coming in noticeably over them is soda-lime.

• Borosilicate 3.3 to ISO 3585 and ASTM E438 Type I Class A, expansion 3.3 against soda-lime's 9
• Thermal shock tested at a 150 K step on finished jars, not quoted from a glass catalogue
• Weights published so a scale can catch a substitution: 390 g at 600 ml, 520 g at 1 L, 660 g at 1.5 L, all with the lid
• 2.8 mm wall, 5 mm base, straight sided, wide mouth, a hand and a spoon both go in
• Lid is SS 304 with a food-grade silicone gasket. No plastic on the jar at all, and no wooden or cork lid that swells shut in a monsoon
• Gaskets and lids stocked as spares. The glass itself does not wear out
• Glass is inert, so oil, vinegar, lime and haldi leave nothing behind and take nothing with them
• Body is oven safe to 300 C without the lid, and freezer safe with two centimetres of headroom for anything liquid
• Borosilicate resists heat, not impact. It is if anything slightly easier to break on a stone floor than a tempered soda-lime jar, and nothing about the word borosilicate changes that
• Never put the steel lid in an oven, and do not take a jar from the freezer straight onto a flame. 150 K is a large step, not an infinite one