DO NOT BOIL WATER

t seems harmless, but microwaving plain water is a real safety risk. If you regularly use your microwave to heat water for coffee or tea, you may be setting yourself up for an ER visit. When water boils in a saucepan, small bubbles form on the bottom and rise to the top; this process allows steam to escape and prevents the water from exceeding 212 degrees Fahrenheit.

If you’re microwaving water in a smooth mug or measuring cup, however, those bubbles may never form. The water can superheat well beyond the boiling point while its surface remains deceptively still. When that excess heat is finally released — usually when you drop in a tea bag or move the cup — the water erupts violently, often scalding whoever’s holding the cup.