by Seth Keipper

Created on: November 19, 2008

The first time I heard about someone heating up water in the microwave only to have it explode upon retrieval I thought that surely this was some urban myth. However upon subsequent research I discovered not only that it can happen, but it will happen unless a few precautions are taken.

Let's get the obvious ones out of the way:

1) Never put metal in the microwave.

2) Never put non-microwave safe dishes, cups or utensils in the microwave.

3) Never put something in the microwave that will be melted by boiling water (or it will melt)

That said, there is no reason not to boil water in the microwave as long as you take some very simple, basic precautions. Rather than list out a rote series of rules I will explain the danger of super heated water and to prevent it with a little common sense.

Water boils when it reaches 212 degrees at sea level, and slightly lower temperatures as you increase altitude. Without going into a chemistry lecture if you observe water that is boiling you will notice bubbles. The process of boiling water involves heating it to a point where the water converts from a liquid to a gas and steam is produced.

By heating water in a glass or otherwise very smooth container the natural irregularities in a metal pot, pan or kettle are absent. This makes it hard for bubbles to form and can actually raise the temperature of water above its boiling point. When something irregular is introduced like a metal spoon, sugar crystal or tea bag the superheated water can form bubbles and will do so rapidly and with sometimes harmful effects.

To mitigate this we can either control the temperature to keep it at or near boiling or introduce something irregular to aid in bubble formation.

Temperature control can be difficult since every microwave heats water differently. However by limiting cook time or working in small amounts we can eliminate danger and wasted energy both. A typical microwave can boil 12 ounces of water in about 3 minutes. Larger amounts can take longer but by heating for 1-2 minutes at a time the danger can be averted.

A much simpler method involves introducing something that bubbles can form on. This can be as simple as putting a toothpick or chopstick into the container, or if you're making tea or coffee you can add the sugar when you first put the water in to heat. Knowing the reasons for why water superheats in the microwave can help anyone easily prevent a dangerous situation.

By not overheating water and by introducing irregular material you will find absolutely no danger in heating water in the microwave.

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