WEBVTT - How Do Rice Cookers Work? 0:00:01.840 --> 0:00:08.760 Welcome to Brainstuff, a production of iHeartRadio, Hey Brainstuff, Lauren Bolebaum. Here, 0:00:10.640 --> 0:00:14.760 Burned chunks or gooey paste can be the disappointing result 0:00:14.920 --> 0:00:18.160 of rice gone wrong, but with the use of a 0:00:18.239 --> 0:00:21.440 rice cooker, the odds even up for even the glutsiest 0:00:21.520 --> 0:00:25.400 in the kitchen. A rice is the staple grain in 0:00:25.440 --> 0:00:28.720 many cuisines around the world. But before the invention and 0:00:28.800 --> 0:00:33.440 adoption of modern kitchen technology alike electric and gas heating elements, 0:00:33.840 --> 0:00:38.080 cooking rice was a finicky, hours long process that required 0:00:38.120 --> 0:00:41.520 you to stand around over a cast iron pot, making 0:00:41.520 --> 0:00:44.440 adjustments to a coal or wood fire in order to 0:00:44.440 --> 0:00:46.839 get the heat just right during different parts of the 0:00:46.880 --> 0:00:51.559 cooking process. Although simple electric rice cookers go back to 0:00:51.600 --> 0:00:55.160 the nineteen twenties in Japan, the first commercial one for 0:00:55.240 --> 0:01:00.520 home use didn't debut until nineteen fifty six from Tashiba. People, 0:01:00.720 --> 0:01:03.680 and perhaps specifically women who often took on the task 0:01:03.920 --> 0:01:07.839 were Ready. Company records show that just four years later, 0:01:08.120 --> 0:01:12.600 about half of Japanese homes had a rice cooker. These days, 0:01:12.760 --> 0:01:15.760 rice cookers range from basic models that'll run you less 0:01:15.800 --> 0:01:18.839 than thirty bucks to ones with fancy features that cost 0:01:18.880 --> 0:01:22.680 over five hundred and Although they're ostensibly meant for cooking 0:01:22.800 --> 0:01:27.680 you know, rice, they can be very versatile. Some people 0:01:27.800 --> 0:01:31.080 use rice cookers as their primary cooking tool for everything 0:01:31.160 --> 0:01:36.200 from spaghetti to spare ribs to scrambled eggs. So today 0:01:36.440 --> 0:01:41.880 let's talk about the technologies behind rice cookers. Rice needs 0:01:41.920 --> 0:01:45.080 two things to go from hard, shelf stable grains to 0:01:45.319 --> 0:01:50.240 tender morsels, lots of water and lots of heat. You 0:01:50.480 --> 0:01:53.760 generally accomplish this by boiling grains of dried rice in 0:01:53.880 --> 0:01:57.080 water anywhere from equal parts of each to twice as 0:01:57.160 --> 0:02:01.080 much water by volume. The rice is done when all 0:02:01.120 --> 0:02:03.760 of the water has been absorbed and or steamed off, 0:02:04.080 --> 0:02:07.120 and the grains are whatever degree of tender you're looking for. 0:02:08.440 --> 0:02:11.360 It is ideal if you can do this without melting 0:02:11.400 --> 0:02:14.000 a layer of rice into a sticky, burnt mass at 0:02:14.000 --> 0:02:17.160 the bottom of the pot. There are a few ways 0:02:17.160 --> 0:02:21.320 to accomplish this automatically. Most start with an electric heating 0:02:21.320 --> 0:02:23.840 element set into a base which can also hold a 0:02:23.840 --> 0:02:27.200 cooking pot. You add rice and water and cover with 0:02:27.200 --> 0:02:29.840 the lid that came with the appliance. The heating element 0:02:29.880 --> 0:02:34.120 heats the pot, which boils the water. But how does 0:02:34.160 --> 0:02:39.200 it know when it's done. The classic technology, the least expensive. 0:02:39.400 --> 0:02:42.959 The type I've got operates on a simple heat sensitive 0:02:43.200 --> 0:02:47.720 magnetized switch. Okay, you turn on this type of rice 0:02:47.720 --> 0:02:50.000 cooker by pressing down a switch on the outside of 0:02:50.000 --> 0:02:53.240 the unit, and when you do, you'll hear a little clock. 0:02:53.639 --> 0:02:56.240 That's because the switch is connected to a lever that 0:02:56.320 --> 0:02:59.240 brings two surfaces in contact with each other that are 0:02:59.320 --> 0:03:03.920 electrically conducive. This completes an electrical circuit and powers the 0:03:03.960 --> 0:03:07.600 heating element. The circuit stays closed because the two surfaces 0:03:07.639 --> 0:03:12.760 are magnetic, but one surface, the upper surface of the pair, 0:03:13.320 --> 0:03:16.000 is made of a material that's only magnetic up to 0:03:16.040 --> 0:03:19.240 about one hundred and two degrees celsius, which is right 0:03:19.280 --> 0:03:23.119 above the boiling point of water. This is a very 0:03:23.280 --> 0:03:27.440 clever bit of physics. Water boils at one hundred degrees 0:03:27.480 --> 0:03:31.440 celsius and won't get hotter than that at normal Earth pressure. 0:03:32.320 --> 0:03:34.800 So as long as there's water in the pot as 0:03:34.840 --> 0:03:37.400 the rice is cooking, the temperature at the bottom of 0:03:37.480 --> 0:03:41.160 the pot will hold steady. At one hundred the temperature 0:03:41.200 --> 0:03:44.680 is in check thanks to the presence of water, but 0:03:44.840 --> 0:03:47.680 when it's all absorbed and or boiled off, the heating 0:03:47.720 --> 0:03:49.960 element can get to work on the pot and or 0:03:49.960 --> 0:03:53.320 the rice itself, which can get considerably hotter than one 0:03:53.360 --> 0:03:57.680 hundred degrees at normal Earth pressure, so the temperature at 0:03:57.680 --> 0:04:01.600 the bottom of the pan leaps up, at which point 0:04:01.880 --> 0:04:05.840 our temperature sensitive magnet stops being magnetic and drops the 0:04:05.880 --> 0:04:08.960 other half of the pair, breaking the circuit and turning 0:04:08.960 --> 0:04:14.000 the heating element off with another little clunk. Except in 0:04:14.040 --> 0:04:16.320 a lot of rice cookers like this, the heating element 0:04:16.360 --> 0:04:19.000 doesn't turn all the way off, but rather switches to 0:04:19.080 --> 0:04:23.400 a warming function. This works thanks to another type of 0:04:23.400 --> 0:04:28.080 heat sensitive switch called a bimetal switch. A bimetal switch 0:04:28.120 --> 0:04:29.800 is a type of switch that's made up of two 0:04:29.800 --> 0:04:34.480 types of metals sandwiched together. Makes sense, right. Each of 0:04:34.520 --> 0:04:37.479 the two is chosen because they are bendable and because 0:04:37.520 --> 0:04:41.520 they expand at different rates when exposed to heat. So 0:04:41.640 --> 0:04:44.560 the switch starts out flat but will bend one way 0:04:44.680 --> 0:04:47.640 or the other at different temperatures because the metals are 0:04:47.640 --> 0:04:52.440 expanding or shrinking at different rates, and you can use 0:04:52.480 --> 0:04:56.440 this property to connect and disconnect a circuit at different temperatures. 0:04:57.400 --> 0:04:59.560 In the case of our rice cooker, at around sixty 0:04:59.560 --> 0:05:03.279 degrees ce elius, that's one forty fahrenheit fairly cool. The 0:05:03.279 --> 0:05:06.400 switch bends and connects the circuit, turning the heating element 0:05:06.440 --> 0:05:10.440 on a butt at around eighty celsius or one hundred 0:05:10.480 --> 0:05:13.960 and seventy five fahrenheit fairly hot. The switch bends the 0:05:14.000 --> 0:05:17.400 other way, breaking the circuit and turning the element off. 0:05:18.640 --> 0:05:21.360 It will keep toggling, holding the temperature of the pot 0:05:21.480 --> 0:05:26.400 nice and warm until you unplug the unit. But of 0:05:26.480 --> 0:05:31.200 course we humans are not confined to manual physical switches anymore. 0:05:32.160 --> 0:05:35.920 Digital rice cookers contain digital thermometers connected to a simple 0:05:35.920 --> 0:05:38.120 computer that can be programmed at the touch of a 0:05:38.120 --> 0:05:40.760 few buttons on the outside of the unit to heat 0:05:40.920 --> 0:05:43.960 or warm the pot, two particular temperature settings, four particular 0:05:44.040 --> 0:05:47.720 lengths of time, like the way that we use standard microwaves. 0:05:48.920 --> 0:05:53.440 Computer controlled rice cookers were first introduced in nineteen seventy nine. 0:05:53.720 --> 0:05:55.840 But if you are going to go ahead and put 0:05:55.880 --> 0:05:58.839 a computer into a rice cooker, why not ask it 0:05:58.920 --> 0:06:02.159 to do a bit more work for you. Rice cookers 0:06:02.200 --> 0:06:04.720 were one of the first home appliances to make use 0:06:04.760 --> 0:06:07.600 of the theory of fuzzy logic, which was developed by 0:06:07.640 --> 0:06:11.239 computer scientists in the nineteen seventies and now helps everything 0:06:11.279 --> 0:06:16.600 from washing machines to refrigerators to subway cars function. Fuzzy 0:06:16.640 --> 0:06:21.480 logic is sort of what it sounds like, logic with variables. 0:06:22.680 --> 0:06:26.320 Digital devices operate on boolean logic, which means ones in 0:06:26.440 --> 0:06:31.000 zeros you know on or off, yes or no. Fuzzy 0:06:31.040 --> 0:06:33.680 logic opens up the field of answers to all of 0:06:33.720 --> 0:06:38.120 the numbers in between one and zero. Devices programmed with 0:06:38.200 --> 0:06:42.400 it can recognize an almost yes versus a slightly yes 0:06:42.720 --> 0:06:47.160 and act accordingly. This lets you program algorithms that take 0:06:47.279 --> 0:06:52.080 variables into consideration, like not just is the pot hot, 0:06:52.360 --> 0:06:55.760 but is it getting hotter quickly, and then make a 0:06:55.800 --> 0:06:58.440 decision about how to control the temperature based on that. 0:06:59.760 --> 0:07:02.640 Idea is that these machines can adjust for the actual 0:07:02.680 --> 0:07:07.400 circumstances occurring in real time. Maybe the ambient pressure is 0:07:07.440 --> 0:07:11.080 making the cooking go faster, or you added too much water, 0:07:11.480 --> 0:07:15.800 and it can cook the rice perfectly regardless. It's way 0:07:15.840 --> 0:07:19.600 better than just using on off temperature settings, and probably 0:07:19.640 --> 0:07:23.080 better than any adjustments a hungry and impatient human might make. 0:07:24.360 --> 0:07:27.280 While fuzzy logic rice cookers function under the same premise 0:07:27.360 --> 0:07:31.280 as basic models, their mathematical programming can deliver a slew 0:07:31.360 --> 0:07:35.920 of customized cooking options, making precise fluctuations in cooking time 0:07:35.960 --> 0:07:40.840 and temperature depending on the programs selected. These may include 0:07:40.840 --> 0:07:45.600 settings for white rice of varying textures, sushi rice, jasmine rice, 0:07:45.760 --> 0:07:50.640 brown rice, germinated brown rice, mixed rices, knge steel cutoats, 0:07:50.840 --> 0:07:55.600 rapid cooking, extended warming, and reheating. And that's just the beginning. 0:07:56.440 --> 0:08:00.840 Some machines have settings for steaming foods, baking cakes, auto cleaning, 0:08:01.240 --> 0:08:03.920 and delayed timers, so you can preset the machine to 0:08:03.920 --> 0:08:08.000 start cooking at a particular time. Oh and if you 0:08:08.160 --> 0:08:11.040 do want a layer of crisp, golden brown rice at 0:08:11.040 --> 0:08:14.120 the bottom of your pot for dishes like tadig, there 0:08:14.160 --> 0:08:17.000 are rice cookers for that too. You add a bit 0:08:17.000 --> 0:08:19.360 of vegetable oil to the pot, and after the main 0:08:19.360 --> 0:08:21.800 cooking is done, a timer holds the pot to the 0:08:21.840 --> 0:08:26.080 heat long enough to crispit. There are also rice cookers 0:08:26.120 --> 0:08:29.200 out there that don't use a standard electric heating element. 0:08:30.040 --> 0:08:33.439 These days, you can find models that use induction heating technology, 0:08:33.920 --> 0:08:36.360 which I could have sworn had already done an episode about, 0:08:36.400 --> 0:08:38.360 but I have not, and I'll have to rectify that 0:08:38.440 --> 0:08:43.360 in the future. Very basically, induction cookers don't waste energy 0:08:43.400 --> 0:08:46.240 heating an element that then heats a pan, but rather 0:08:46.400 --> 0:08:50.439 use magnetic fields to heat the pan directly. There are 0:08:50.480 --> 0:08:54.199 also pressure rice cookers, which seal and pressurize their contents 0:08:54.280 --> 0:08:58.080 to allow for faster cooking times and hotter temperatures. Pressure 0:08:58.080 --> 0:09:02.080 cooking also a whole different episode. Whatever kind of rice 0:09:02.080 --> 0:09:04.920 cooker you're using, there are all kinds of recipes out 0:09:04.960 --> 0:09:06.679 there for how to get the most out of it. 0:09:06.840 --> 0:09:10.600 When it comes to rice and beyond, at a certain point, 0:09:10.679 --> 0:09:13.320 it's a hot pad with a fitted pot. Anything you 0:09:13.400 --> 0:09:16.160 want to warm or cook, especially anything involving a lot 0:09:16.160 --> 0:09:18.920 of liquid, can be done in a rice cooker with 0:09:19.200 --> 0:09:23.440 enough tenacity a rice cooker. Poached fruit, hard boiled eggs, 0:09:23.679 --> 0:09:27.800 homemade soups, whatever you're cooking in it. Take a moment 0:09:27.840 --> 0:09:31.280 to appreciate your humble or not so humble rice cooker, 0:09:31.920 --> 0:09:34.320 and if you don't have one, consider picking up a 0:09:34.320 --> 0:09:38.320 basic model. After all, it's a robot that, if it 0:09:38.400 --> 0:09:41.640 could want things, would want you to eat good rice. 0:09:42.480 --> 0:09:49.719 That's a good robot to have around. Today's episode is 0:09:49.760 --> 0:09:52.600 based on the article how rice cookers work on HowStuffWorks 0:09:52.600 --> 0:09:55.480 dot com, written by Jessica Tooothman for more about the 0:09:55.559 --> 0:09:58.280 history of rice cookers. Check out my other podcast Savor 0:09:58.640 --> 0:10:02.760 for the Warm and Fuzzy rice Cooker episode. Brainstuff is 0:10:02.760 --> 0:10:05.319 production by Heart Radio in partnership with how stuffworks dot 0:10:05.320 --> 0:10:08.000 com and is produced by Tyler Klang. But four more 0:10:08.040 --> 0:10:12.120 podcasts from iHeartRadio. Visit the iHeartRadio app, Apple Podcasts, or 0:10:12.160 --> 0:10:14.000 wherever you listen to your favorite shows.