Do you need boiling water for drinks or recipes? A small amount of water can be easily boiled in the microwave for just a few minutes without heating the stove or turning on the electric kettle. However, this also does not mean problem free. For example, although small, the risk of superheat is still possible. In these circumstances, hot water will spurt suddenly, potentially causing burns. While the risk is small, there are some easy steps you can take so you can boil water in the microwave safely.
- Preparation time: 1 minute
- Boiling time: 1-3 minutes
- Total time: 2-4 minutes
Step
Choosing a Microwave Safe Container
The first step to ensuring the safety of boiling water in the microwave is to use the right container. This easy-to-understand table will help you determine if a container is suitable for use.
| Ingredients | Microwave Safe? | Notes |
|---|---|---|
| Glass | Yes | |
| ceramic | Yes | |
| Paper plate | Yes | |
| Oil paper/parchment | Yes | |
| Most metals (including aluminum foil and silverware) | No | Metal heated in a microwave can give off sparks that damage the microwave or even cause a fire. |
| Brown paper bag | No | Can cause a fire due to the release of toxic fumes in the microwave. |
| Tightly closed/airtight container | No | May explode due to formation of hot steam. |
| Disposable containers (yoghurt containers, butter, etc.) | No | May melt, burn, or emit toxic fumes. |
| Plastics (wrappers, Tupperware-like containers, etc.) | Usually not | The harmful chemicals in plastic can contaminate food. However, plastic containers labeled "microwave safe" by the FDA may be used. |
| Styrofoam | Usually not | See the information on the plastic column; some Styrofoam containers labeled "microwave safe" can be used. |
Part 1 of 2: Boiling Water Safely
Step 1. Pour the water into a microwave-safe bowl or cup
First, pour the water into a container made of microwave-safe materials as listed in the table above.
Make sure the container is not tightly closed. A boost of hot steam may cause a dangerous explosion
Step 2. Place a clean, microwave-safe object in the water
Next, place a non-metallic object such as a wooden spoon, chopsticks, or ice cream stick into the water. This will prevent superheating by allowing water bubbles to form.
- Superheating occurs when water in a microwave heats up above its boiling point, while water cannot bubble because there is no "nucleation" point (a rough surface that allows bubbles to form). As soon as the water splits and the "nucleation" point is formed, the superheated water will quickly turn into hot steam and cause a small explosion.
- If you don't have a non-metallic object that can be submerged in water, use a container that has scratches or shards on its inner surface. These scratches or splinter will act as "nucleation" points that help the formation of water bubbles.
Step 3. Put the water in the microwave
Heat for short periods of time (eg no more than a minute and a half), stirring periodically until the water evaporates. Even after this step, the water bubbles may not be as obvious as they are in the pan. The most accurate way to make sure the water is boiling is to measure it with a thermometer. At sea level, water boils at 100°C. The temperature of boiling water drops at higher altitudes.
If you use a container that retains heat well (such as glass or ceramic), be careful when removing the water from the microwave for stirring. Use a towel or protective gloves to avoid burning your hands
Step 4. To sterilize the water, continue to boil the water
If water is boiled for purification, microwave it long enough to kill any microorganisms in it. The Centers for Disease Control and the US Environmental Protection Agency recommend boiling water for at least 1 minute, or 3 minutes at an altitude above 2000 m above sea level.
Part 2 of 2: Avoiding Superheat Hazards (Advanced Tips)
Step 1. Do not heat the water for too long
If after reading the steps in the previous section, you're still worried about overheating when boiling water, there are other things you can do to make sure it's safe. For example, perhaps one of the most important things you can do to prevent superheated water is to "don't overheat it." If the water doesn't go above its boiling point, it won't get super hot.
The boiling time of the water can be adjusted according to the power of the microwave. To be on the safe side, first of all, limit the boiling time to 1 minute. Based on the first result, adjust the next boiling time
Step 2. Avoid using very delicate containers
For the same reasons you should put non-metallic objects in water or use scratched containers, you shouldn't use very smooth containers. Examples include new glass or ceramic bowls. However, a variety of other fairly delicate ingredients can also trigger superheats.
Preferably, use an old container that is worn or looks scratched so that it has a "nucleation" point for water bubbles to form
Step 3. Tap the sides of the container when you are done boiling the water
After the water has been heated for a long time, check for superheating by tapping firmly on one side of the container before removing it from the microwave. Ideally, do this step using a "long object" to protect your hand.
If the water is super hot, tapping on the container can cause an "explosion" on the surface of the water. Water may spill in the microwave, but since it hasn't been removed, you'll be safe from burns
Step 4. Stir the hot water with the long object while it's still in the microwave
Still not sure if the water is super hot or not? Stir with a long stick or stick to make sure. Inserting an object and breaking the surface of the water will create a "nucleation" point for bubble formation. The super hot water will explode or overflow soon. If not, congratulations, safe water is issued!
Step 5. Keep your face away from the water container until you are sure it is safe
Although this seems obvious, it is worth emphasizing again to "keep your face away from the water which is at risk of super heat". Most injuries from superheated water occur when someone takes water out of the microwave and looks into it. Explosions of superheated water at this point can cause serious burns to the face and in the worst case, permanent vision damage.
Warning
- A cup of water with nothing in it such as chopsticks is a greater risk of superheating because bubbles have nowhere to form. Putting something in the water is a small but very important step.
- Do not put a closed container of water in the microwave. The hot steam generated can cause the container to explode and contaminate the microwave.
