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Follow these steps to safely heat water in the microwave
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Need some boiling water for a beverage or culinary project? Small amounts of water can be conveniently boiled in the microwave in minutes, without the trouble of heating water on the stove or turning on the electric kettle. However, this isn't without its own difficulties. For instance there is a small, but real risk of super-heating, in which the hot water erupts suddenly, possibly causing burns. While this is unlikely [1] X Research source , there are precautions to help boil the water safely.
- Prep time: 1 minute
- Cook time: 1-3 minutes
- Total time: 2-4 minutes
How Long to Boil Water in a Microwave
The time it takes to boil water in a microwave will differ depending on what kind of container you’re using, how much water you’re trying to boil, and how powerful your microwave is. As a very general rule of thumb, heat water for 2-3 minutes to bring 1 cup (235 mL) of water to a boil.
Steps
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Pour the water into a microwave-safe cup or bowl. Boiling water with a microwave is remarkably easy. To start, pour the water into a container made of the microwave-safe materials listed above.- Make sure the container is not sealed shut. A buildup of hot steam can cause a harmful explosion.
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Place a clean, microwave-safe object in the water. Next, put a non-metallic object such as a wooden spoon, a chopstick, or a popsicle stick in the water. This prevents a dangerous problem called "super-heating" by giving the water something to form bubbles on.- 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.
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Put the water in the microwave. Heat in short (e.g., no more than one and a half minute) intervals, stirring regularly until the water is steaming. Even if these steps are followed, bubbling may not be obvious as it would be on the stove. The most accurate way to ensure the water is boiling is to use a thermometer. At sea level, water boils at (212° F; 100° C); this temperature decreases at higher altitudes.
- 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.
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To sterilize water, keep it boiling. If you're boiling water to purify it , heat it in the microwave long enough to kill the microorganisms. The Centers for Disease Control and the Environmental Protection Agency recommend boiling the water for at least one minute, or 3 minutes at altitudes above 6,562 feet (>2000 m). [6] X Research source
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Don't heat the water for excessively long stretches. If, after reading the advice in the section above, you're worried about a superheating accident when you try to boil water, don't worry — there's more you can do to keep yourself safe. For instance, perhaps the single biggest thing you can do to avoid the risk of superheated water is to not heat it for long periods of time. If your water isn't heated past its boiling point, it can't become superheated.- 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.
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Avoid extremely smooth containers. For the same reason that it it's a good idea to add something non-metallic to your water or to use a container with scratches in it, it's a bad idea to use perfectly smooth containers. Examples of these can often include new, pristine glass and ceramic bowls, though a variety of other materials can also be smooth enough to cause problems.- Instead, use an older, more worn container or one with visible scratches at the bottom — these will create nucleation sites for bubbles to form.
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Carefully tap the side of the container when it finishes heating. Once you believe you've heated your water long enough to get it hot, check for superheating by firmly tapping on the side of the container before you take it out of the microwave. Ideally, this should be done with a long tool to protect your hands.
- 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.
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Stir the hot water with a long object while it is in the microwave. Still not sure whether the water is superheated or not? Stir it with a long rod or stirring stick to know for sure. Introducing an object and disturbing the water gives it nucleation sites to form bubbles — if it is superheated, it will rapidly burst or boil over. If it doesn't, congratulations! Your water is safe.
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Keep your face away from the container until you are sure it is safe. This may seem like it goes without saying, but it's important not to put your face anywhere near water that you think may have even a tiny risk of being superheated. Most injuries from superheated water result when a person removes the water from the microwave and looks into the container — a sudden burst of superheated water at this point can cause serious burns on the face and even permanent vision damage in the worst of cases.
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Community Q&A
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QuestionIs it safe to boil water in the microwave?This answer was written by one of our trained team of researchers who validated it for accuracy and comprehensiveness.wikiHow Staff EditorStaff AnswerThe main risk of boiling water in a microwave is that it might become superheated, which can cause boiling water to violently “explode” out of the container. If you use precautions such as putting a wooden stirrer in the water or using a container with a rough inner surface, you’re less likely to experience this issue.
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QuestionCan I boil water and then put macaroni in it to cook in the microwave?Community AnswerYou can put both water and macaroni in a bowl before heating, ensuring the noodles are covered completely by water, and cook it in the microwave for about seven to eight minutes. You might want to put a plate under the container, as it might bubble over.
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QuestionWhat else can a microwave do?Community AnswerThe main use for microwaves is to reheat food faster than possible in a stove or oven. There are many recipes and products that are made specifically for use in a microwave.
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Warnings
- Do not put a sealed container of water in the microwave. The expanding water vapor can cause the container to burst open, creating a huge mess!Thanks
- A mug of water without something in it, like a chopstick, has a much higher risk of superheating because the bubbles have nowhere to gather. Putting something in with the water is a small but really important step.Thanks
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References
- ↑ http://www.snopes.com/science/microwave.asp
- ↑ http://www.realsimple.com/food-recipes/tools-products/cookware-bakeware/food-containers-safe-for-microwave
- ↑ http://www.iflscience.com/technology/what-happens-when-you-put-metal-microwave
- ↑ http://lifehacker.com/what-should-and-shouldnt-i-microwave-1532532172
- ↑ http://www.snopes.com/science/microwave.asp
- ↑ http://wwwnc.cdc.gov/travel/yellowbook/2010/chapter-2/water-disinfection.aspx
About This Article
Article Summary
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If you want to boil water in the microwave, pour the water into a microwave-safe container. Add a clean, microwave-safe object like a wooden spoon or a popsicle stick into the water to prevent it from super-heating, which may cause the water to erupt suddenly. Heat the water in short intervals of no more than one and a half minutes, stirring regularly until the water is steaming. If you don’t see bubbles, use a thermometer to monitor when the water reaches 212°F. Keep reading for more tips on how to avoid super-heating the water.
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Reader Success Stories
- "Like every other college student, I have stocked up on ramen in preparation for finals week. This morning, I wanted to make myself one of those Styrofoam cups full of it that you're supposed to add boiling water to. I had never heard of superheating before now, nor have I heard of putting a microwave-safe item into the water. I couldn't find anything nonmetal to use, so I just used some of the dried ramen noodles from the container and it worked great! Ramen was perfect. Thank you!" ..." more
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"Like every other college student, I have stocked up on ramen in preparation for finals week. This morning, I wanted to make myself one of those Styrofoam cups full of it that you're supposed to add boiling water to. I had never heard of superheating before now, nor have I heard of putting a microwave-safe item into the water. I couldn't find anything nonmetal to use, so I just used some of the dried ramen noodles from the container and it worked great! Ramen was perfect. Thank you!"
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"I'm staying in an SRO, a shelter that looks like an apartment. It doesn't have the cooking gas on, hence no cooking, so it's been cold salads, sandwiches, or microwaved food. I enjoy my tea, and wanted to know the proper way of boiling water in the microwave. I also learned in your Q&A that it's possible to also cook pasta in water in the microwave. I'm not sure how long I'll be here, but this will help make my life a little bit more comfortable while I am here."
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"Had I not read this, I could have been hurt really bad. Never heard of superheated anything, so the instructions probably saved me or my microwave. I will be cooking noodles in once water hot, but will follow instructions exactly. God bless you."
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"Very helpful. My elderly father wants to make an occasional cup of instant coffee in the microwave or possibly heat up a Pyrex bowl to make boiling water for Jello. Your explanations of hazards and how to avoid them - good to know!"
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"The chart was especially helpful. The article was a good reminder about super heating - something I learned the hard way by pouring Jello into super heated water (no injury, just a fright and a mess), but had forgotten."
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