Return to the Appliances Forum | Post a Follow-Up

 o
Testing portable Induction Plate

Posted by chas045 (My Page) on
Mon, Dec 31, 12 at 11:14

I had heard such good things about induction cooking that I picked up an Aroma 1500 watt Induction hot plate at COSTCO. I thought it would introduce me to induction cooking and speed up heating water for coffee. Unfortunately, I had forgotten that much stainless steel is non-magnetic. Most of our cookware is Revere Ware and it doesn't work. However we had two kettles. One turned out to be non-magnetic as well but the other, while lighter, does work on the unit.

I was already considering returning the unit since I couldn't produce any other quickly available cook pots except my cast iron pans and dutch oven. However, I wanted to see if it was indeed faster. I tested several containers with 4 cups of cold tap water. I compared them with my Hamilton Beach electric kettle and found all convection methods to be slower rather than faster. My light weight kettle took 5:10 m:sec vs the 4:45 for the HB electric but other methods were slower still. I thought heavy iron might be best. I had a little old le creuset baby dutch oven that took 6 minutes and I tried a 10 inch cast iron skillet that took at least 7 minutes.

I choose the heavy iron items because of their extra iron and because they were all that I had available. Perhaps a heavier normal kettle would have given better results? Perhaps the extra time for the heavy iron is due to overcoming the specific heat of the metal while the light kettle had insufficient ferrous material to get maximum efficiency.

In any case, at least for quick heating, this unit is a failure. Does anyone have corrections or additions to my testing methods? Have I missed something obvious?


Follow-Up Postings:

 o
RE: Testing portable Induction Plate

Your induction plate is a 110v unit and not as powerful as a 220v cooktop. I use an electric kettle to heat water too, but I use the cooktop to bring water to a boil and keep it boiling for pasta, etc. which an electric kettle will not do.


 o
RE: Testing portable Induction Plate

Chaos045:

Countertop induction units, as jxbrown points out, simply lack the power to demonstrate the much-vaunted speed of induction on cooktops or stoves.

What it can demonstrate for you is induction's adjustability and control and, hopefully, evenness of simmer-type heating at low settings.

When jxbrown says your Aroma unit is only a 110v-120v unit, that means you have a hot plate. If you think of the Aroma as a hotplate, is there really any disappointment that it does not perform like a much more powerful unit.

I mean, if you had a small portable butane burner, how would you expect its performance to compare with, say, that of a 22K btu-hr gas stove burner on a Blue Star range? Or, what would you expect when comparing a .65 KwH coil-burner hot plate with a 2.5 KwH coil-burner stove burner?

To be sure, it is possible to get countertop induction units that run from 220v-240v circuits. Cooktek has several such units in its product line. Those are fully as powerful as any stove or installed-cooktop induction unit, and maybe more so. But those are also three to six times more expensive than most 120v induction hotplates and you need to have a spare 240v outlet, too.

The Aroma's max power rate is 1.5 KwH (that is what they mean when the specs say "1500 watts.") Actual power may be rather less. There is a review/discussion on Chowhound where I think somebody measured the Aroma unit and found it typically pulled no more than "1200 watts" (1.2 KwH).

Compare that to induction stoves and cooktops. The biggest burners pull at least 3.4KwH on boost (and some units will pull far more than that.) Even the smallest induction hobs on a stove are often capable of pulling 2.4 KwH, which is twice the power available from the Aroma unit. You can see where folks would see greater boiling speed from a much more powerful unit.

Your electric kettle is a dedicated device with might called "direct coupling" to the water. Most of the ones I've seen have been rated at 1.5 to 1.8 KwH and the heat goes directly to the water without having to deal with space around a burner, and the imprecise coupling of pan to burner that can slow down kettles on most stoves and cooktops.

So, back to your original question, the thing to test with your Aroma unit is control and adjustability. Try melting and holding chocolate on the low settings. If you have or can borrow an induction suitable pressure cooker, you might experiment with that. Also, you might try making stove-top rice.

Maybe others can suggest more tests?

Of course, you did get the unit from Costco so there should be no problem taking it back for a full refund.

This post was edited by JWVideo on Mon, Dec 31, 12 at 13:56


 o
RE: Testing portable Induction Plate

I'm cross posting to Cooking as the OP did.

I clearly have too much time on my hands, so I repeated chas's experiment. I brought 4 cups of tap water (64F according to my thermopen) to rolling boil (201F at our altitude) on our Thermador induction cooktop and the Braun hotpot. On the cooktop, in a stainless pan, it took 2 minutes 3 seconds. In the hotpot it took 2 minutes 42 seconds.

The reason chas's times are longer than mine are because we have 50A available to the cooktop which can deliver around 4.5 kW of energy. I don't recall what the maximum power of the hotpot is. It seems to be higher than the Hamilton Beach chas used.

The 110V, 1.5 kW induction hotplate isn't a good proxy for an induction cooktop. I would use the induction hotplate for supplemental heating if I needed to use a lot of extra pots and pans, but never for my main cooking.

18/0 stainless is commonly used for induction-ready cookware (see link below). Stainless has poor thermal conductivity. Cast iron, while ferromagnetic, is heavy and also has poor thermal conductivity. It heats slowly and transfers heat poorly. However cast iron, once heated, will maintain its heat for much longer than steel. Bottom line - a steel pot will get water to target temperature faster than cast iron simply because it is thinner and lighter. Neither is ideal because of the low thermal conductivity.

I invested in a set of 18/0 stainless with aluminum disc bases, and these work well on induction. Costco sells a set of about 8-9 pots and pans with lids for $160.

Hope that answers some of the OP's questions.

Cheryl

Here is a link that might be useful: induction cookware

This post was edited by jadeite on Mon, Dec 31, 12 at 15:18


 o Post a Follow-Up

Please Note: Only registered members are able to post messages to this forum.

    If you are a member, please log in.

    If you aren't yet a member, join now!


Return to the Appliances Forum

Information about Posting

  • You must be logged in to post a message. Once you are logged in, a posting window will appear at the bottom of the messages. If you are not a member, please register for an account.
  • Please review our Rules of Play before posting.
  • Posting is a two-step process. Once you have composed your message, you will be taken to the preview page. You will then have a chance to review your post, make changes and upload photos.
  • After posting your message, you may need to refresh the forum page in order to see it.
  • Before posting copyrighted material, please read about Copyright and Fair Use.
  • We have a strict no-advertising policy!
  • If you would like to practice posting or uploading photos, please visit our Test forum.
  • If you need assistance, please Contact Us and we will be happy to help.


Learn more about in-text links on this page here