Turn on the kettle and bring the water to a boil. [substeps] Don't use more water than you need, otherwise the kettle will waste energy heating the extra water.
[header] How to check the freshness of baking powder [title] Boil some tap water. [step] Use tap water and fill a kettle to the minimum fill line. You only need ½ cup (118 ml) of hot water to test the baking powder, but filling the kettle to the minimum fill line will ensure the heating element doesn't overheat.