Problems heating up pans on an induction hob

carbon-steelinductionstainless-steeltemperature

I bought an induction hob to precisely control pan temperature; it’s a 2000W Hendi single hob, temperature and power can be combined independently.
I tested two De Buyer pans with it, a multilayer stainless steel and a carbon steel one; I heat them up empty and checked surface temperature with a thermometer.
I noticed that the temperature quickly jumps well over the set value and takes time to stabilize; this is especially true when I try to reach 100+ celsius and with carbon steel cookware the effect is magnified (I got a blue ring mark in the middle of the pan).
What am i doing wrong? Should I start to cook immediately?

Best Answer

Any electrical device that is used to maintain a constant temperature (ovens, induction hobs, immersion cookers, even thermostat-based space heaters) does so by first sensing whether the current temperature is below the set temperature. If so, the heating element/induction coil/etc... is turned on. Once the temperature reaches some upper threshold, the element is turned off again, and the cycle repeats.

Different devices have different ranges of thresholds. For instance, the temperature in an oven may vary by as much as 30°C, while an immersion cooker will keep the temperature range withing 1°C or so.

The reasons your hob overshoots the set temperature, then takes some time to stabilise, can be:

  1. The hob is built to operate on a much wider range of temperature thresholds than you thought.
  2. The hob is built to keep a pan with contents at a constant temperature, but heats up too powerfully for an empty pan (i.e., the hob makes the 'assumption' that there is something in the pan, and delivers power based on that assumption).
  3. There is some distance between the hob's temperature sensor (often in the center) and the induction coil (a ring some distance from the center), and your pan does not conduct heat instantly. Then, while the pan has reached target temperature at the spots closest to the induction coil, it is still below the target temperature at the hob's sensor, causing the hob to add more power.

Using an empty pan will make points 1 and 3 worse as well. You can check if any of these are occuring in your case by heating a pan of water, and taking the water temperature (points 1 and 2), or by moving your surface thermometer to different spots in the pan (point 3). If the issue turns out to be 1, there is not much you can do. If it's either 2 or 3, you can mitigate the problem by starting to cook (almost) immediately.

Alternatively, you could force a slower heating curve by starting the hob at its lowest temperature and manually changing the temperature setting every minute or so.