Induction Cooktops with temperature control

Request a Test
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I was looking for an induction cooktop that would allow me to control the temperature, not just the power. Choice has reviewed induction cooktops and portable induction cookers but has glossed over the significant difference between temperature control and power control, and has not discussed or evaluated how temperature control is gradually appearing (claimed and real) in induction cooktops, how it works, which products actually use real temperature control and how well individual products perform (i.e.how accurate are temperature settings, and how well do they regulate to keep to that temperature). This is a request to significantly improve and update current reviews. More background below is from a post I wrote under electric frying pans.

Currently available examples that do appear to offer real temperature control include a Siemens product already reviewed and below expensive products, but others claim temperature control and we consumers need to be able to separate those that do from those that donā€™t. Many would benefit from an explanation of the use of temperature control vs power control, benefits and limitations of each:

the Control Freakā„¢ Home | Breville (US) (may not be available in AU yet, but the commercial version is)

TOKIT Smart Induction Cooker Pro ā€“ TOKIT AU (a cheap one)

https://www.impulselabs.com/product (this is a curiosity, certainly not available here, includes a 3KWh battery!)

ā€“backround from my previous post in another topic---------------
I burn things too often with my induction cooker which is controlled strictly by power, not temperature. I wondered about replacing my induction cooktop with one that had good temperature control. I went to Choice articles to learn a bit about how successful and widespread are temperature controlled induction cooktops, but was disappointed to find no useful info.There are huge advantages to be had from temperature control for cooking, at least for frying. But as ever, the topic turns out to be complicated, and sadly, not one that Choice has unravelled for us. Their reviews on induction cooktops donā€™t tell us anything about temperature controls, how good they are, how they work, what is the difference between one which has a ā€œfakeā€ temperature scale and one which attempts to sense temperature (apart from the Siemens model which it mentions requires special cookware, but no comment on how well it (or any others) set and regulate temperature).

Temperature control of induction cooktops is difficult because as pointed out, where and how does the controller measure temperature? Ideally for liquids you would have a sensor in the liquid. This is impractical for day-to-day use and you could always use a standard food thermometer for manual control anyway (but see my answer elsewhere about a product that does this). The real problem is measuring frying temps, something you canā€™t do with a cooking thermometer because you canā€™t attach it to the pan surface (though with difficulty, you can manually use a handheld Infrared thermometer with some success on black pans, but not shiny ones (unless you use my trick which is definitely a topic for another time and place), so this too is impractical for day to day use).

Apparently the only currently realistic way for an induction controller to measure pan temperature is to use an infrared sensor inside the heating coil looking up at the bottom of the pan through the ceramic cook top (see reference below *1). Call this method (1). This determines temperature by the characteristics of the radiation coming off the pan bottom. It is technically difficult, however if you know the radiative characteristics of the pan you can actually set the temperature to within a few degrees, and even if not, you can still regulate temperature well i.e. keep the pan at a constant temperature.

Another method (2) relies on a temperature sensor bonded to the underneath of the ceramic glass cooktop. This can never be accurate because of the delays in heat getting from the pan to the glass and though the glass, and the resulting temperature gradient. (Remember that a selling point of induction is that the glass doesnā€™t get very hot, so wonā€™t be as hot as the pan).

It remains a mystery to consumers what a manufacturer means when they put a temperature scale on their induction cooktop, and therefore how accurately you can set and regulate temperature. My guess is that the Siemens system works well. If you use their pans and set a temperature, the pan will end up close to that temperature. If you use other pans (with different IR emissivity as you mention), the temperature might be way off, but it will still regulate and maintain a constant but unknown temperature. Other manufacturers might approximate some kind of temperature control, but can hardly be accurate, and any using method (2) will be poor at regulation as well. Some manufacturers seem to put a temperature scale alongside the 1 to 9 power settings. This is just a fiction because the temperature will have little relationship to power - at any setting the pan will start cold and get hotter until limited by thermal losses into the pan, food, and environment. Potentially this can be very hot ā€“ pan-melting temps ā€“ though all cooktops have some kind of rudimentary over-temp protection for this reason. The point is that a power setting says nothing about the resulting pan temperature. Presumably manufacturers use a mix of all these and possibly other methods, and the consumer has no way of knowing which and how well they perform. That is, unless Choice tells them, and so far this has not been discussed or tested.

It is worth pointing out that some kinds of cooking donā€™t require temperature control, and are better handled by controlling the power - eg boiling and simmering. Temperature control is not useful for these because the temperature of the food is always very close to 100C. The rate of boiling can be usefully varied by changing the power, but not by changing the temperature from 100C to 100.001C.

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For others interested in the topic of temperature controlled cooking, there is some relevant information in another thread that may be of interest.

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The best steaks Iā€™ve had have been cooked over a camp fire - no idea in the world what temperature that was!
But a little more seriously, who cares? unless you are trying to mass produce (mass cook) something in a commercial setting, the temperature is best left to the skill of the cook. (Or as in an oven, we put the sensor into the meat) What is required in mass cooking is repeatability, I suggest.
As you correctly point out, temperature settings are an approximation at best.

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I think the point is the important difference between cooking by setting power or by setting temperature. Setting power is best for boiling and simmering, setting temperature is very useful for frying (including but not only, deep frying) and of course for high sugar cooking like jams and toffees. Some cookers are capable of accurate temperature settings. Others on the market just make up fictitious temperature scales related to power that do not regulate or measure temperature at all. A third group do try to measure and regulate temperature but are not very good at it, so can be quite inaccurate. It would be helpful to know which are which.

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My Westinghouse portable cooktop has a temp scale, and I use it, but I donā€™t believe itā€™s accurate at all. I simply have a notion of what will work. I burn more if I use the power scale except for doing my boiled eggs.

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Agree it would be useful, however is essential to be a successful home cook to have an induction hob which can maintain a constant preset temperature, and the accuracy of the set point? To also ask if relying on a temperature control, how one goes about calibrating for differences in cook ware (Temperature emissivity)? Or to note the temperature in the pot of the ingredients or at the top surface of the pan that is important. For any pot or pan there will always be a thermal gradient between the underside and the upper surface in contact with the food/ingredients. What is in the pot/pan and method also changes the profile. Possibly a few degrees. Perhaps more. Some interesting challenge questions for the Choice testing staff to consider. Especially if one looks to how the better known TV chefs control the cooktop - gas or induction.

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I agree there are too many variables to make a recommendation that fits all cooks with all cookware. I learned how to cook by ā€˜cooking and paying attentionā€™ to learn what settings work for what foods with my cookware. Every new pan requires ā€˜recalibrationā€™ over the first few uses. Also, most recipes state ā€˜high heatā€™, ā€˜medium heatā€™, ā€˜low heatā€™ and so on, hardly accurate enough to convert to a specific power or temperature that itself may or may not translate to the temperature inside the pot or pan, or the other pot or pan.

Many recipes and advices state the proper temperature of the food when cooked. That thermometer test is part of learning to cook noting high heat and lower heat can each ā€˜get thereā€™ but the texture, evenness, and appearance of the food could vary widely depending.

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Very little of what we buy today is essential, and Iā€™m not suggesting this feature is either. Iā€™ve cooked mostly successfully for decades without cooking control by temperature. But temp control would save me burning the oil or accidentally braising instead of frying, without having to splatter water drops or other methods of checking temp, or guessing. The sources of potential inaccuracy have been discussed above.

You can get temperature control for years with electric frypans, but that is an extra appliance.

All Iā€™m saying is that temperature control is a useful claimed feature that is recently available on some induction cooktops; some claims are false, some do it better than others. It would be useful to know which models do this, and how well.