The quick and straightforward answer would be:
Yes, they can.
But there is one major problem with it. Rice cookers are created for speed. So they bring the temperature up fast. Rice is absorbing the vapor produced out of water content in the container/bowl.
Now I won’t go to the details of how rice cookers work, as I have its own article about it here. It will be fiddly, but it will work.
As you are here clearly for the information and not the debate, let’s get to it.
Although I am a bit against using devices for something else than their purpose, I do get into a sticky situation from time to time. There can be a moment in which you need to do things a bit differently.
So pull your toque (chef’s hat) aside, and let’s get into some freestyle cooking.
Can it be done?
As I have mentioned in the beginning, yes, it can. But you will have to watch over your creation more than you would like.
The reason is that the rice cooker tries to do its best by bringing water to a boil as fast as possible. He does this to create steam, which is absorbed by rice to make it into that extraordinary delicious fluffy thing we all love.
Once the rice cooker runs out of water/steam, the inner temperature rises above 212°F (100°C), and it either shuts off entirely or switches itself to warm. On warm can be the temperature, that ranges from 140°F to 150°F (60°C to 65°C) kept up to 12 hours.
And this is the root of our problem. It usually takes 20-40 minutes to make rice in a rice cooker. Afterward, it ideally switches to keep warm and stays like that for some time. As the temperature for a switch is the boiling point, e.g., 212°F (100°C), it takes approximately 10 minutes to drop to keep the warm temperature.
But the slow cookers take at least 4 hours to make anything. The magic of a slow cooker is in a long time it takes to cook anything. You throw all the ingredients together and go to work, watch some TV with your loved ones or focus your attention on the side dishes.
I know it may sound a bit boring, but I do believe that understanding these differences makes a world for you in this endeavor.
How to do it?
As I have mentioned above, it takes between 20-40 minutes to cook rice in the rice cooker. The amount of water determines the time. Once it is gone, the cooking is turned off, and keep warm is activated.
To bypass this, you will have to add liquid in the rice cooker, pretty much every time it does the switch. In theory, you could add a lot of liquid at the beginning and hope that it will be enough for the whole process.
But there is a small problem with that.
We are trying to bend the rice cooker a bit and force it to function as a slow cooker. And the slow cooker is not always boiling. It takes time to get even to the simmering point.
If you are interested in more details about the slow cooker’s temperature, I do recommend this article about the topic.
So how to cheat our way through? The only way I found that is at least semi-functional is to wait every time on the keep warm function to kick in. Afterward, lift the lid off the rice cooker and add water, broth, sauce, or any other liquid that rhymes well in your recipe.
Before you start the process again, I do recommend waiting at least 10 minutes, so the temperature has a chance to drop. We are simulating the slow cooker after all, so it is beneficial to play with the heat a little bit.
Yes, it will be like on a roller coaster, but I do think there is a better way how to do this. You are not looking for the temperature to drop further below.
I am aware that I am suggesting playing around with the food temperature, and it will sound a bit naive. But you still have to consider the temperature stability. It is a way smaller hit for the food to fluctuate between 140°F (60°C) and 212°F (100°C) than between 75°F (24°C) and 212°F (100°C).
You are playing with the temperature quite a bit, and most of the time, the liquid content is boiling, you have to change your way of cooking to accommodate for this slightly.
You will quickly learn not only to add quite a bit of liquid but add and mix ingredients in a different order.
For example, you cannot add your protein too early, as it will overcook quickly. In the beginning, it is a guessing game. I would love to give you an exact timing for every ingredient, but it depends on your recipe and rice cooker.
The golden rule to apply here is the longer it takes to cook, the sooner it should be in a rice cooker. Also, if you want to enjoy something crunchy like peas or corn, it should be added in the end.
In regards to what to cook in a rice cooker, you can do a quick search on the internet, and you will find a ton of awesome recipes. One of the most beautiful lists that I have discovered is Lifehacker’s one that you can find here.
So to answer the original question can rice cookers be used as slow cookers, is yes they can. But you have to make a few adjustments to the cooking process and the ways you use for cooking your masterpieces.
Is it passable? Of course, it is, but I would still recommend using slow cookers for slow cooking and rice cookers for rice cooking.
I hope you found this information helpful and will be waiting for you in one of my other articles.
Until next time I wish you a happy and relaxed cooking.