When deciding how to heat water, it can be accomplished in a variety of ways. For smaller amounts of water, such a glass or bowl’s worth, taking the time to boil over the stove can be time consuming and require multiple pieces of dishware. That’s why we turn to the microwave as a much more convenient option for boiling and heating water.
Yes, you can boil water in microwave. No current research shows negative health effect. BUT, the thing that concerned people is when the water become superheated without forming bubbles which can lead to an eruption by a sudden move. Read "superheating" section below, and how to avoid that.
How do you boil water in a microwave safely? To boil water in a microwave without injuring yourself or the microwave, you must place the water in microwave-safe container and set the timer dependent on the amount of water and the wattage of the microwave. Upon removing, protective wear should be used, or time should be allowed for sitting to prevent injury.
For most microwaves, it should take between 1-3 minutes to boil water. Sometimes it takes longer, I have a more detail breakdown for you below, keep reading.
Using a microwave to boil water is a safe and efficient way to reach these desired temperatures. Taking the necessary precautions when boiling water will help to keep you safe. We will dive deeper into the steps to boiling water in the safest and most effective way as well as the benefits to boiling in a microwave opposed to other heating methods.
How to Boil Water in A Microwave
Boiling water in the microwave is not the most complicated process in the world, but there are some important steps and things to check along the way. This will ensure that you are staying safe when completing this process. Microwaves, regardless of wattage, have the ability to make items incredibly hot, posing the risk of burns and fire damage.
Here you’ll find the steps you should take to boiling water in a microwave in a safe and contained way for quick and effective results.
- Pick A “Microwave Safe” Container
You will need a container in which to put the water in to boil. This container needs to be safe to put in a microwave, like this one here, which means that there is risk of damage to the microwave, the contents inside the container, or the container itself. These containers should not have lids as built-up steam can be dangerous and cause an explosion.
You are probably wondering which containers are deemed safe in the microwave. Here is a convenient list of the containers you can and cannot use when trying to boil water in the microwave. Paying attention to these items will allow for successful boiling and prevent unsafe materials from entering your water.
Containers Deemed Safe
These containers will have no issues in the microwave, but be aware that they may be hot when you remove them:
- Glass and ceramic dishes
- Wax or parchment paper
- Paper plates
- Paper towels and napkins
- Anything labeled microwave safe*
*On many containers and dishes, it will say “microwave safe” on the bottom. If this is there on items in question, you can put it in the microwave. You should be aware that if the item is not made of one of the materials listed above, it is slightly riskier (especially if it is plastic).
Containers That Are Not Safe
You should not put these items in the microwave as they are typically not as durable or may cause fires and other problems:
- Aluminum Foil - You should keep any metal away from the microwave to be safe. Aluminum specifically can cause fires or damage the microwave by creating sparks.
- Dishware with metal or paints - Metals and metallic paints should also be avoided for similar reasons to those presented with aluminum.
- Cold-storage plastic: These include the containers that you keep cottage cheese or butter in. They are made of toxic plastics that can be harmful if they melt or burn.
- Brown paper bags - The thin paper can catch on fire and emit toxins.
- Sealed containers - Lots of hot steam can cause the seal to burst off, creating a mess and potential damage.
- Plastics - Try to avoid most plastics in the microwave. Tupperware and similar containers may be okay but usually are not the best because the chemicals from these items can seep into food. If it is deemed “microwave safe” you can use it.
- Styrofoam - The only Styrofoam containers you should use are those noted as “microwave safe.” Styrofoam has chemicals that can be toxic as well but unlike may claims that it is always unsafe, some can be microwaved.
- Plastic wrap - Some are deemed microwave safe, but as a general rule, try to avoid putting this in the microwave.
Try to avoid these materials if you can, especially when boiling water as you will be microwaving for a longer period of time than heating up smaller foods. The longer cook time presents greater opportunity for melting or burning of these materials.
We will dive into more detail about microwave safe items and more general safety later in this article!
- Pour Water into Container
Now that you have chosen the container you will use to boil the water, fill your cup or bowl with the desired amount of water you want. There are a couple of things you should be aware of when filling the cup for safety and practicality:
- Do not fill to the ledge - When water boils, bubbles will arise. This may cause the hot water to spill over the edge and give you something to clean up once you are done.
- Water level may decrease - Boiling water emits steam, and this will mean that some of the water is evaporating. If you leave the water in the microwave for too long, it could not only risk superheating (water reaches temperature above boiling point and may lead to explosions), but also give you less water than you wanted.
- Do not seal container - As mentioned, you should not keep a seal on the container because it will lead to trapped steam that may cause an explosion and either damage the microwave or the container you are using.
If you avoid these issues, pouring the water into the container is very simple. It is suggested that you also put a microwave safe object into the water. This should be an item that does not contain any of the materials indicated on the “unsafe” list above. Wood is your best choice. This could be a wooden spoon or a popsicle, for example.
The reason you put something in the water is that if your water goes past the boiling point, it may not have something to form bubbles on in the water. Giving a microwave safe item for it to make bubbles on will prevent this overheating. Containers with chips or cracks can also replace the item and act as the area for bubbles to form.
- Put Water in the Microwave and Cook
Place the water in the center of the microwave plate as this will help to boil the water as evenly as possible from all sides. For most microwaves, it should take between 1-3 minutes to boil water. This is largely dependent on the wattage of your microwave. If you know the wattage, this is a general breakdown of how long it will take to boil water.
These are based on one cup of water. If you plan to boil more than one cup, you should expect boil time to be longer:
- 1,200 watts: 1.5 minutes
- 1,000 watts: 2 minutes
- 800 watts: 2.5 minutes
- 700 watts: 3 minutes
- 600 watts: 4 minutes
If you do not know the wattage, it is usually included in the owner’s manual, on the inside of the microwave, or on the back. You can also see how long it takes to boil one cup of water to determine the wattage for future cooking.
It is recommended that you boil water in intervals, not allowing cook time to exceed over 1.5 minutes with each pause. This will prevent superheating as steam starts to form. You can stir the water in each of these intervals and continue to cook until the desired time has been reached. Boiling water in the microwave does not produce obvious bubbles like on a stove.
Boiling points are lower at altitude. For every increase in elevation by 500 feet, the water’s boiling point is decreased by 0.9 Fahrenheit (or 0.5 Celsius). If you live in areas at higher elevation, you can expect the time it takes for your water to boil to be less.
- Safe Removal
Once you have successfully boiled the water, you must now remove it safely from the microwave. This is important as most containers that are microwave safe will still be very hot once the water has been boiled. You should take precautions when removing this container so that you do not burn yourself.
If you want to use the water while it is boiling, you will want to remove it when it is still very hot. Consider using an oven mitt or cloth towel to protect your hands upon removal. This will allow you to carefully take something out of the microwave without burning yourself on the container itself or the hot contents that could spill over.
Keep your face and skin away from the container right after heating as the steam is very hot, and there could be a chance of explosion from superheating. The most important thing to do when removing something from the microwave is to protect your body. Taking the necessary precautions in this somewhat dangerous endeavor can easily be made safe with attention.
Dangers Associated with Boiling Water in The Microwave
You will want to take the necessary steps to boil water safely in a microwave because there are inherent dangers in dealing with very hot water. There are two primary dangers that can result from water being boiled in a microwave: (1) burns resulting from the hot water and container and (2) superheating.
Boiling water reaches 212 degrees Fahrenheit, making both the water and the container it is heated in incredibly hot. Exposure to either of these with bare skin can cause burns or scalding. This could lead to blistering and, if not taken care of, infections. You should wear protective wear when taking the water out to prevent exposure.
In the event that you do burn yourself, you can take these steps for relief and healing:
- Apply cool water - Cool water can be run over the burnt area for upwards of 20 minutes to provide relief for the burn. Make sure this water is not too cold, which can be too stark and cause greater pain. Ice should also be avoided with the drastic difference in temperatures.
- Cover burn - Use a moist bandage or a clean cloth to cover the affected area. This will help to prevent infection and foreign matter from entering the area.
- Elevate - If you can, try to elevate the burn above heart level. This will help to increase blood flow and reduce swelling.
- Leave blisters alone - If blisters form, do not poke or pop them. These take time to heal on their own, and if they are touched, could become infected or interfere with the healing process.
This is one of the most common dangers in dealing with heating water and cooking anything in the microwave. You can easily avoid this by protecting your skin and using proper equipment when removing items.
Superheating is an issue that is specific to boiling water in the microwave and will not likely result from heating water elsewhere. Superheating is when water is brought to a temperature over its boiling point. This can be particularly dangerous in that water bubbles do not form as easily in a microwave, and this can lead to an explosion when the water is stirred.
Once you take the water out of the microwave and stir it or add any type of powder, this will cause violent bubbling and explode out of the container. This can be avoided by making sure that water is left in the microwave for the proper amount of time to boil it and to allow bubbles to form.
Bubbles often will not form because they have nothing to cling onto. This is why it is suggested to put a microwave safe item in the water so bubbles can easily form. If you do not do this, try using older dishware that may have a crack or imperfection. Smoother containers make the forming of bubbles more difficult. Most saucepans are not this smooth, so there is no issue.
When the microwaving is complete, try tapping on the container carefully with a long spoon or something that will protect you. The tapping will trigger any water movement if superheating has occurred. This issue is most specific to microwaves and can be easily avoided by following the steps mentioned in putting the water in and taking it out of the microwave safely.
Additional Tips for Safety
Beyond the steps and dangers already proposed to keep yourself safe when boiling water in the microwave, there a few extra things to be mindful of.
Look More Deeply At “Microwave Safe” Options
Beyond the listed materials you can use and those you should try to avoid when microwaving any container, there are some things you should look for and mini tests you can do to determine what truly is safe.
To make sure a container is microwave safe, these are the things you should look for:
- Look for microwave safe on the bottom of containers - This could say “microwave safe,” have a dish with a wavy line above it, lines of waves, or a triangle with a number in it on the bottom of a container. There are seven types of plastic, those labeled “5” are microwave safe, “1, 2, and 4” are typically safe, and “3, 6, and 7” should not be microwaved.
- Test your container - If you are not sure if a container is safe, place it in the microwave empty. Put a second container with a cup of water next to it in the microwave. Microwave for one minute. If the empty container is cool, it will be microwave safe. If it is warm, only use it to reheat items, and if it is hot, do not use it in the microwave.
Why should you care about what is considered microwave safe? There are many health risks associated with some of the containers that people use that can get into their food. These are high in toxins and can contaminate what they are cooking or heating. Most of these containers that cause problems are made of plastic.
Some of the side effects of consuming items from containers that are not microwave safe include:
- Birth defects or miscarriages
- Decreased sperm counts
- Hormone disruptions
- Neurobehavioral changes
- Early puberty
These can be the result of plastic materials seeping into the water you are boiling or toxins being emitted into the air when being heated in the microwave. These plastics may melt or burn, which is harmful to both humans and the environment.
Heat Based on Time
On a stovetop, we usually know that water has reached the boiling point once we see bubbles starting to form. Because bubbles are much more difficult to see and have less of an ability to form in a smooth container in a microwave, you should base boiling off of time.
This will further eliminate the risks of superheating. Based on the wattage of your microwave, set the time for boiling in accordance with this and the amount of water you plan to boil. Going off of this time will be the safest way to ensure boiling without injury. Microwaving water should take 1-3 minutes for one cup of water, depending on the wattage and elevation level.
Using a microwave and boiling water is a simple task that young children are capable of doing. It is safest for you to supervise children nonetheless. Because of the risk of superheating and touching very hot microwave safe containers, make sure that they are using the proper protection for their hands and are not too eager to pull hot items out of the microwave.
Children should be made aware of the risks in boiling water in a microwave and be instructed to keep their bare skin and faces away from the steam and hot containers. Teaching young children about these risks early will help to prevent accidents and potential injuries.
You should also not leave children alone when you are boiling water in a microwave. Small children may become curious and try to open the microwave before it is complete or when it becomes increasingly hot. Microwaves should be placed at a height where young children cannot easily access them.
Studies related to trauma and acute care have reported that 68% of microwave burns for children between one and four years old were the result of pulling items out of the microwave by themselves. Water was one of the major items that caused these injuries. Most microwaves are not childproofed, making it essential that they are supervised near a running microwave.
Why You Should Boil Water in A Microwave
While there are risks associated with heating anything in the microwave, doing so actually has multiple practical benefits. These will not only help to save you time but also lead to more efficiency and health benefits.
Boiling water in the microwave is a much quicker process than boiling water on the stove or in a kettle. You can have a cup of boiled water as quickly as a minute and a half versus the 10-15 minutes it takes to boil over a flame. This can be a great solution if you are short on time or just do not have the patience to wait for the water.
Microwaves are able to cook food and heat water more quickly because the microwave causes the molecules in the water to shake rapidly. Heat energy is sent directly to the molecules in the water, allowing them to heat more quickly than other cooking methods. Items that are heavier in water content will cook faster than those that are not.
While this will not save a significant amount of energy compared to the other ways, you can save energy in your home, microwaving uses less energy than many other cooking and heating methods. Microwaves save a significant amount of energy compared to conventional ovens and gas-powered appliances.
Oftentimes people will boil water on a stove, which can use more energy depending on if it is gas or electric. Gas stoves use 40% more energy than a microwave does. Typically, electricity is more expensive than gas, but is used in much smaller doses in that things can be cooked more quickly to save more overall energy.
If you want to sterilize water, using the microwave is a quick and efficient way to do so. This is the way in which you can ensure water is purified for whatever reason you may be using it. To sterilize water, it will require longer heating time than bringing water to a boil. You will want to boil the water for at least 1 minute longer and even up to 3 minutes past the boiling point.
The longer time in which you microwave will give a chance for the boiling water to kill all the microorganisms that may be infecting the water. Some may not be confident in drinking their tap water but want to use it. By sterilizing this water, bacteria and organisms will be killed off.
Because you will be microwaving the water for a longer time beyond its boiling point, you put yourself at a higher risk for superheating. Make sure you place some sort of microwave safe item in the water. A chopstick could also be an easy solution to this problem. Most tap water will have enough air in it to avoid this, but sitting water is at a greater risk.
Safely Boiling Water in the Microwave
Now you have all the necessary steps and knowledge associated with boiling water in the microwave. It is one of the easiest ways to heat water quickly, but can also be the most dangerous if care is not taken to the smaller details. Make sure you follow all the steps to prevent your boiling water from overheating, which can lead to explosions.
Safely boil water by ensuring you are using a microwave safe container and that you are boiling the amount of desired water for the proper amount of time. You should then remove the container with hands that are protected by a cloth or oven mitts due to the high temperatures. These three steps are the most important in safely boiling water in the microwave.
By following the steps and tips listed throughout the article, you will be able to have the water you want boiled in a quick and efficient way. You no longer have to wait 10-15 minutes for that cup of tea to be ready or for your instant noodles to be made. The microwave is an incredible tool for cooking many things, and boiling water is one of the easiest tasks to tackle with it!