We use blown, heat resistent tempered glass.
Maximum temperature differential 100C/212F.
Take care when using a microwave as heating beyond recommended temperature (above boiling point) will adversely affect the temepering and may cause the glass to shatter.
Sudden temperature changes may break or shatter the glass:
Do not pour in cold liquid when cup is hot, or conversely boiling liquid when the cup is very cold.
Do not place cup in a wet sink or on a wet cloth when hot
Do not wash with abrasive cleaners or steel wool
Yes, but please not the temeperature tolerance recommendations above. Always keep the plug vent open when carrying boiling liquid to prevent steam build up.
For best results, rinse in boiling water prior to filling.
Fitment with lid.
When placing the lid onto the tumbler you want to hear a distinct "click", letting you know the lid is been securely fastened.
The glass differs in ovality and circumference, similarly colour and ambient temperature changes can cause subtle changes in the lid diameter. As a consequence each KeepCup Brew is hand fitted with its lid to ensure perfect fit.
To care for the product always use the matching lid.
If cleaning in a dishwasher, allow the lid to cool completely before fitting. If the lid becomes mishapen in the dishwasher, wash again unimpeded and the place on the cup while warm. It should return to shape.