Ever wonder how that rice cooker knows when to shut itself off? Ain't that a smart machine? And to boot the rice comes out right no mater how much you cook!

Well the truth is that the rice cooker doesn't know it's cooking rice or anything else for that matter. What it does know is temperature, that's it. Read on my inquisitive friend...

Look inside your rice cooker with the cooking pot removed and you'll notice a spring loaded button in the center on the bottom. That button it the whole trick. What does the button do? Well the button contains a thermostat and a spring. The thermostat (like in your air conditioner system) senses temperature. The thermostat operates an off-on switch. Here's what happens. (we'll get to the spring in a moment). 

We put raw rice and tap water in the cooker portion of the pot, turn it on and depress the "cook" button (a switch). The heating element comes on and the rice begins to cook, very simple. The water temperature will only get so high, and, with the water in the pot the temperature of the bottom of the pot stays around 212ºF. In a sense the water is controlling the temperature of the pot. Well, when the water boils out the heating coils just keep heating because that's all they know how to do. The bottom of the cooking pot begins to get hotter than the boiling temperature because the water is not there controlling the temperature. The thermostat senses the rising temperature and, at a preset temperature, tells the cook button to activate (the "ding").

The "ding" switch (cook button) pops up causing the heating coil to go from "cook mode" to "warm mode". 

Now to the spring under the button. The spring keeps the button touching the cooking pot at all times, it's always pushing against it. So if the pot overheats at anytime the thermostat will catch it and go to warm mode. It's very important to keep that button and the bottom of your cooking pot clean for proper temperature transfer.

How does the rice come out right no matter how much you cook? 

A certain amount of rice takes a certain amount of time to cook with a certain amount of water. That's why we always measure rice and water proportions "exactly". The rice cooker doesn't know time it only knows temperature.

It's common sense that one cup of water will take longer to boil out than 2 cups of water right?  Well them smart ole rice cooker pot makers figured that out and marked the cooking pot so you actually put a little less water in for each cup of rice. This would help reduce the cooking time some. A quick check of this theory gave me these results. Now remember a cup of cooked rice in a rice cooker is 3/4's of a cup of raw rice.

1 cup rice  - uses 1.5 cups of water
2 cups rice - uses 2 3/4 cups water
3 cups rice - uses 4 cups of water

Now... go brag to your friends about how smart you are!.. oh, and tell them about Cooking Louisiana too...

Thanks
Jack