The replacement infuser for 300ml Glass cup is made with heat resistant borosilicate glass.
Please note that this infuser will only fit the 300ml glass cup sold by The Tea Makers of London.
Top rack dishwasher and microwave safe.
Note: Our borosilicate glass teapots are heat-resistant rather than heatproof. If the ambient temperature in the kitchen is low, warming up the teapot before use will help the teapot last longer. This will help the tea to steep more effectively if the water doesn't lose heat to the teapot. Once you've poured in the boiling water, avoid resting your teapot on the cold surfaces, instead use a trivet or kitchen towel. These simple precautions can help the teapot survive longer. Glass is less likely to break or shatter if we warm it up gradually.
Even the most heat-resistant glass, like this borosilicate glassware, is subject to shattering under thermal shock. http://en.wikipedia.org/wiki/Thermal_shock
Borosilicate glass: Borosilicate glass is widely used for laboratory glassware. Borosilicate glass has excellent thermal properties with its low coefficient of expansion and high softening point, it also offers a high level of resistance to attack from water, acids, salt solutions, organic solvents and halogens.
Most of us are more familiar with this type of glass in the form of ovenware and other heat-resisting ware, better known under the trade name Pyrex.
Borosilicate glass is made mainly of silica (70-80%) and boric oxide (7-13%) with smaller amounts of the alkalis (sodium and potassium oxides) and aluminium oxide.
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