Induction Hotplate - CHOICE # 364

Cooking with an induction cooker in the kitchen may be a relatively new experience for many a chef when it comes to Chinese cuisine.

But for the domestic users, their priority is more with the safety rather than culinary performance of such appliance - the built-in type induction hotplate.

To investigate recent media reports on the safety of these cookers, the Consumer Council has conducted a test, in collaboration with the Electrical and Mechanical Services Department, on 10 models of induction hotplates with double stoves.

With input power rating from 2,600 W to 4,800 W, these induction hotplates are comparable to the gas cookers for use in the kitchen.

One of the safety concerns commonly related to induction cooking is the harmful magnetic radiation that these appliances may pose to users. 

The test could find no evidence to support such concerns. The magnetic flux radiation of all models were measured to be lower than the limits in the International Commission on Non-Ionizing Radiation Protection (ICNIRP) guideline.

Regarding the construction, the test found in one model, it failed to switch off automatically nor manually by the user when boiling water spilled over the hotplate, and cracks were found on the top ceramic plate of another model during impact test - both models cannot comply with standard safety requirements.

Further, a number of special operation tests was performed to simulate potential abusive use. 

In one test, three cans of food were placed atop the hotplate stove with the power switched on. 4 of the samples were shown to be able to detect the absence of a suitable utensil and cease operation automatically, while the remainders, however, continued heating up the cans at high and/or low power settings.

While leaving food cans atop an open fire continuously may pose similar hazard, the risk with hotplate is higher due to its flat surface.

Consumers should, therefore, be mindful of leaving food cans over the flat hotplate, and always keeping food preparation clear of the stove lest objects could be misplaced on the hotplate.

In another test, two pairs of forks and spoons were placed atop the hotplate, all samples were able to detect such objects and ceased to activate the heating.

There have also been concerns that users wearing metal accessories like steel watch would turn on the hotplate, magnetic bracelet and rings may be more vulnerable to magnetic radiation exposure from the induction cookers.

But the test could find no proof as these accessories could neither be passed by the hotplate as a suitable utensil to start any heating, nor be heated up by the magnetic radiation during cooking.

• Some useful tips on induction hotplate usage:
• Use induction cooking compatible utensils - usually made of stainless steel or with a stainless steel bottom.
• Never use a hotplate with cracked or damaged surface.
• Do not switch on the electricity supply to the hotplate until the hotplate is ready for use.
• Do not put too much soup to avoid splashing over the hotplate when boiling.
• Cover the utensil, if possible, to save energy.