Make sure the container is not sealed shut. A buildup of hot steam can cause a harmful explosion.
Super-heating occurs when water in the microwave heats water past its boiling point and the water is unable to form bubbles because there are no nucleation sites (essentially rough spots for the bubbles to form on). As soon as the water is disturbed or a nucleation site is introduced, the built-up superheated water forms steam very quickly, causing a small explosion of boiling water. [5] X Research source If you don’t have any non-metallic objects to put in your water, use a container that has a scratch or chip on the interior surface. This will act as a nucleation site to help the water bubble.
If you’re using a container that holds heat well (like a glass or ceramic one), be careful when you take the water out of the microwave to stir it. Use a towel or potholder to protect yourself from burns as you handle it.
The exact amount of time you’ll want to limit your heating sessions to can vary based on the strength of your microwave. To be safe, try limiting your heating to a single one-minute segment at first. Based on how hot the water gets from this first heating attempt, you can adjust your next one accordingly.
Instead, use an older, more worn container or one with visible scratches at the bottom — these will create nucleation sites for bubbles to form.
If the water is superheated, tapping the container can cause it to suddenly “burst” over the top. This may spill water into the microwave, but since you haven’t removed it yet, you should avoid any burns.
If the water is superheated, tapping the container can cause it to suddenly “burst” over the top. This may spill water into the microwave, but since you haven’t removed it yet, you should avoid any burns.
