I saw a ‘smart’ waffle iron that signaled when the waffle was done cooking, and it got me wondering about how the iron ‘knows’ when the waffle is cooked.
As background, my waffle iron at home is twenty years old, and is definitely a dumb appliance. Back when it was new, it had a light that indicated when there was power going to the heating coils. When the iron reached its target temperature (there’s a thermostat control, but I doubt that it’s a thermocouple - probably a coiled bimetal strip), the light would go out and you’d put the batter in. The light would then stay off, and the signal to check the waffle for doneness was the light turning back on. I assume that this meant that the temperature of the iron had dropped far enough that the heating element had to kick back on. This would never be quite done enough, so you’d have to wait a bit and pull the waffle after another 30 sec or so. Anyway, it seemed that the idea was that the iron temperature would fall, unpowered, until it passed some lower threshold and that fall of temperature represented enough heat transferred to the batter to cook it (in theory if not practice).
Now, with a smarter modern device, I can imagine that the iron immediately electronically senses the drop in temperature from the addition of batter, but what would it do after that to determine waffle doneness in a clever way? Would it let the iron temp fall, unpowered, for a certain number of degrees like my old iron does? Would it immediately apply power to counter the cooling and only consider the waffle ‘done’ once the iron temperature got back up to some target value? Would it look for inflection points in the heating curve to indicate that most of the moisture in the waffle had been converted to steam and the waffle was starting to dry out? Some combination thereof?
Its a little bit more than a timer. As the raw material will cool the skin of the waffle maker, it can detect when there is raw food in there.
It triggers the timer when the skin of the waffle maker rises again to reach browning temperature.
Then it times how long it is at browning temperature.
The inside of the waffle should be cooked too, as the skin of the waffle won’t reach browning temperature while there is substantial water inside, and the effect is that as that water is being dried out, it holds the temperature at boiling temperature… the conversion of water to water vapour takes away the heat from the waffle maker ( thats called the latent heat of evaporation … the amount of heat each bit of water takes when it converts from liquid to gas… ) and so there’s no increase in temperature in the food while its still wet and steaming.
So would a smart waffle iron cook all waffles at the same temperature, but for different lengths of time, or would it cook waffles at different temperatures for the same length of time in order to achieve different levels of browning?
I guess that this is an intersection of how browning works and how best to control electronic appliances…
I’ve been making waffles since the 50s and I don’t think you are correct in describing the way an older waffle iron works.
The (many) irons I’ve used have a light (actually, it was a small glass lens that allowed you to see the heating coil…when it’s lit, the coil is on). You allow the iron to pre-heat to a temperature determined by the heating adjustment dial. The coil stops heating and you are ready to put in the batter. When the batter hits the iron and you close the iron, the coil comes back on because the iron is now below the desired temperature. When the iron has again reached the desired temperature, the waffle is done. This is because the batter has heated to the point where it has lost enough water to be fully cooked. At this point, the coil stops heating and the “light” goes out. Newer waffle irons may operate differently, but the whole idea is that the waffle is done when the heating element turns OFF.
The alternate method is to simply wait until the steam from the batter drops significantly. I usually do this instead.
TL;DR: The light goes OFF to show the waffle is done, not ON. YMMV.
OK, my wife just read this thread and opined that I’m incorrect. She also assumed that the light comes ON when the waffle is done.
No…the two waffle irons I have now (one is less than two years old) have lights that come ON when the unit is heating. The lights go OFF when the desired temperature has been reached. Therefore, the lights go OFF when the waffle is (supposedly) done cooking.
Am I in the minority? Is everybody opening waffle irons when the light comes ON? The instructions for both of mine specifically say to wait until the light goes out.
As I said earlier, wait until the steam drops significantly. Much better approach.
“Plug in the waffle maker, and wait for the indicator light to turn off. Pour about 2/3 cup of batter into the lower grid of the machine. Spread the batter evenly over the cooking surface with a wooden spoon, and then close the lid. Wait for the light to come back on, and then check the waffle by lifting the lid. If it is not browned, close the lid again and then recheck it once you no longer see steam coming out of the machine. Remove the waffle from the iron with a spatula.”
The only way this makes sense to me is if the iron cools, unpowered, as the batter cooks, with the response of the thermostat being laggy enough that a enough time passes between the batter being added and the element kicking back on for the stored heat of the metal plates to have cooked the waffle - or nearly enough, anyway. Entirely thermostat based, no timer, and not very accurate or effective, since you always had to leave the waffles in for more time.
I agree with the instructions, but I do not agree with your interpretation. The iron reaches a temperature set by the thermostat. You add the batter, which immediately cools the iron, so the thermostat turns the heating element on. When it reaches the same temperature again, the thermostat turns the heating element off and the waffle is ready. DO NOT rely upon the “stored heat” of the iron. The heating elements should be on the whole time the waffle is cooking.
In my experience, people do two things wrong when they use a waffle iron. First, they set the thermostat too low and allow the iron to cycle repeatedly. Just set the temperature to a high point where the waffle is done when the thermostat turns off…period. The longer the waffle stays in the iron, the worse the result. Second, many people make the batter too thick. The water in the batter will make the waffle lighter, with more bubble and crispness. The batter should be soupy, like a thick cream soup. It shouldn’t be like cake batter.
This is just my opinion, but I’ve been making waffles for a LOOOOONG time.
You are correct. When the batter goes in, the heating element immediately cools and then kicks on to reheat (which lights the light, which is really just a window to the heating element). The iron is carefully designed so that when the light (the heating element) once again goes off, your waffle should be done.
My waffle iron is a cheap, dumb appliance that I like because it makes the perfect shape (square, thin) and size of waffle. The plates are removable and reversible, and there is no temperature sensor in the plates themselves. So any temperature sensing is done in the air surrounding the heater coils. I can’t crack open the thermostat unit because it is riveted closed, but I doubt very much that it is electronic.
When plugged in, the light (which, yes, is just a window onto the heating coil) gradually ramps up, and then clicks off when the iron reaches its goal temperature, as the instructions state. When batter is added, the light does not immediately turn back on - I don’t bother to time it, but it’s a couple of minutes before it snaps back on. According to the instructions, that’s when I’m supposed to check for doneness, but experience teaches me that I have to wait a bit longer. There is no heating going on for that first couple of minutes, because the thermostat is laggy. If I wait for the light to turn off a second time, the waffles are overdone, again because of that thermostat lag. Setting the temperature of the iron higher only gets me waffles that are burned on the outside while being gooey inside. If I wanted to set things so the waffle was done when the light went out a second time, I’d have to set the goat temperature lower.
Perhaps in a well-engineered unit with a rapidly responding thermocouple wired right to the plates, you could immediately sense the drop in temperature of the plates and add power accordingly, which is what I suggested in my first post. But that’s not how my current waffle iron operates. In a well-designed unit, it may well be that optimum cooking is achieved just as the plates get back up to starting temperature and the heater kicks off a second time, but again that’s not the case with my iron.
I totally understand, and everybody is welcome to his/her choice of waffle iron. I avoid this type of waffle iron for two reasons: First, the thermostat DOES lag behind the temperature of the cooking surface, which doesn’t seem like a very good way to regulate the cooking temperature. (On the other hand, I’ve never had one lag behind by a couple minutes. It’s 20-30 seconds at most.) Second, God intended for us to eat round waffles, not square waffles. If your waffles are square, they lack fundamental waffleness.
My waffle maker is 60 something years old
(Yes it still works fine)
It works on the principle of lift the lid and check it yourself.
And dont forget to brush it with oil, or you are not getting your waffle
It makes awesome round waffles though, will probably outlive me