Why Your Rice Cooker Is Foaming & How to Prevent It

While using a rice cooker is extremely easy, especially if you’re using it to make rice, that doesn’t mean that you will never encounter challenges. One of the most common issues that arise when using a rice cooker is excessive foaming and bubbling, which can then leak out of the cooker and onto the surface below. 

Rice cookers can foam due to the excess starch within the rice, alternatively, it can be due to too much water in the basin of the cooker. To prevent this wash the rice beforehand to remove the starch and don’t overfill the basin within the rice cooker.

In this article, I am going to talk about why your rice cooker may be foaming, how it happens and what you can do to prevent it.

Reasons Your Rice Cooker Foams

There are two major reasons that your rice cooker is foaming: the starch content in the rice and the amount of water in the cooker. 

Excess Starch In the Rice

Rice is a naturally starchy food, and any rice you use will have starch present in it. However, some varieties of rice have a higher starch content than others. 

When you start your rice cooker, the water mixes with the rice, including the starch. When water combines with starch, you get large, foamy, soapy bubbles, which grow and rise to the surface of the liquid in the cooker, expanding and bursting as the rice cooks. 

If the bubbles reach high enough, this expansion and bursting process can affect the cooker’s lid. When it is moved, the bubbles – or foam – have enough space to spill outside. 

The foam can then fall onto the surface on which the cooker is placed. 

Aside from being difficult to clean up, this type of foam can cause your rice to be overcooked and soupy, forcing you to cook a new batch. 

Too Much Water In the Cooker

The bubbles mentioned above form naturally when rice is being cooked in a rice cooker. It is only if they reach high enough that they spill over, becoming an issue for you. 

The reason these bubbles can reach high enough is the amount of water in the rice cooker. If you’ve added too much water to the basin, the bubbles can travel higher and potentially reach the cooker’s lid. 

At the same time, to cook rice properly, it’s crucial to have the correct ratio of rice to water before starting your cooker. 

If you suspect there’s too much liquid in the cooker, you’ll have to reduce both the amount of water and rice in it to ensure that the final product is delicious, fluffy rice that’s perfect to the taste. 

Preventing Your Rice Cooker From Foaming

If your rice cooker has already started foaming, there’s not much you can do, and there’s a good chance that the rice inside is already too soupy to be palatable. However, you can take steps to ensure that you don’t have to worry about such a situation in the future. 

rice, soy sauce and chopsticks on a black background

Some options you should consider for reducing the risk of your rice cooker foaming include:

Wash Your Rice

As mentioned above, one of the biggest causes of a foaming rice cooker is an excess of starch in your rice. Since you won’t be able to tell if the rice you’re using has too much starch, the best option available to you is “washing” the rice before placing it in the cooker. 

To wash your rice, you should:

  • Pour your rice into a bowl, and add water to the bowl. Room temperature tap water will work fine. 
  • Stir the rice in the water with your hands.
  • You’ll find that the water will turn cloudy as you move the rice around. This is the starching that’s being removed from the rice. After a while, pour out the starchy water. 
  • Repeat the first three steps until you get clear water when “washing” your rice. This means that there’s no more starch in the rice that can be rinsed off, and the grains are ready for cooking.

Soak the Rice

If you don’t have the time to wash your rice, you can let it soak in water for about 30 minutes, which will release excess starch without tiring you out. To remove the most starch possible, wash the rice once after it’s finished soaking. 

An added benefit of soaking your rice is that it makes it easier to cook. As the grains lie in the water, they absorb this liquid, making them softer, and reducing cooking time. 

Use a Different Rice

If the rice you’re using is high in starch, washing and soaking can be time-consuming processes that you may not be able to complete every time you want to cook rice. 

Instead, consider changing the type of rice you buy. There are two major types of starch in rice: amylose and amylopectin. 

Amylopectin is the type of starch that is more likely to cause your rice cooker to foam over, as this starch results in greater bubbling. As a result, it’s best to opt for rice that is high in amylose and low in amylopectin.

Most long-grain rice is higher in amylose, making them a great option if you’re looking to reduce the risk of foam while cooking. Some popular varieties that meet these requirements include Basmati and jasmine rice. 

Additionally, brown rice generally has a lower starch content than white rice, so opt for brown rice where possible. 

Add a Little Oil or Butter

Oil and butter both form a layer on top of the liquid in your rice cooker which prevents the bubbles from rising to the top. This prevents them from disturbing the cooker’s lid. 

You don’t need to add too much – just a dash should do the trick. 

You can either add it to the rice cooker after adding the rice and water or use it to toast the dry rice before cooking. Toasting rice in oil or butter before cooking with a rice cooker will result in thicker rice after fully cooked, making this technique perfect for dishes like pilaf. 

Olive oil is the most popular option for people adding oil to their rice cookers, thanks to its neutral flavour and multiple health benefits. Alternatively, you can use a different type of oil or flavoured butter to impart a mild flavour to your rice. 

An added benefit of adding oil or butter to your rice cooker is that it will prevent the rice from sticking to the sides of the cooker, making serving it significantly easier.

Confirm You Haven’t Overfilled the Rice Cooker

As discussed above, too much water can increase the chance of your rice cooker foaming over. To avoid this from happening, make sure you haven’t filled your cooker too much. 

Check the capacity of the cooker to make sure you’re not adding too much rice. 

Additionally, make sure you add the right proportion of water and don’t go overboard. If you feel your rice cooker is too full even after following the guidelines in the instruction manual, remove a little rice and water until you feel comfortable with the level. 

After all, cooking another serving will be much easier than handling the extra clean-up a foaming rice cooker can produce

Cook Gently

Cooking gently is the perfect option if you’ve already started your rice cooker without washing your rice or have overfilled the appliance. Lower the heat on your rice cooker, allowing the rice to simmer

The reduced temperature lowers the chances of foam spilling over out of the cooker. 

If some foam does spill out, open the cooker and skim it away. Make sure not to jostle the rice, as that will increase the risk of your rice turning soupy. 

If the foam is building quickly, lowering the heat further is possible. 

If doing so is not possible, stop the cooker and allow the rice to sit and absorb the water. If necessary, start the cooker once again. This will allow it to finish cooking, taking the steps mentioned above to reduce the risk of the cooker foaming over once again. 

Check the Lid

If you’ve experienced numerous instances of foaming when using your rice cooker previously, there’s a chance that you may have damaged your cooker. 

Check the vents on top of the lid to make sure that they are clear and not clogged with dried starch. If these are blocked, the steam from your rice will not be able to escape, increasing the risk of your cooker foaming over.

If the vents are clogged, you will need to clear them out. 

Using sharp objects to do so can damage the lid of your cooker. Instead, use a toothbrush to gently scrub the vents and remove any accumulated starch, allowing you to use your cooker without the risk of further foaming.