It is important that you let boiling water settle (stop bubbling) before pouring it into a tableware item. Therefore avoid using boiling water directly from a Quooker or from a kettle.

If the item is cold its suggested to pre-heat it with hot tap water. Pouring boiling water directly into a cool handmade cup, bowl or mug may cause the item/ glaze to crack.
The cracks will not affect the life cycle of the product and glaze will not fall off.