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Thread: INDUCTION HOB AND TEMPERATURE CONTROL

  1. #1
    zydecogary Guest

    Default INDUCTION HOB AND TEMPERATURE CONTROL

    INDUCTION HOB AND TEMPERATURE CONTROL

    There has been a lot of interesting talk about an induction hob. Let
    me say that I've owned one for about 2 1/2 years and I'm in love
    with it. I purchased my unit from the Home Shopping Network, on sale
    for $79. It was their Wolfgang Puck model with timer, watt control
    (1400 to 400), and temperature control (400-150 F). It was so useful
    that I pulled out an electric burner from my GE stove and placed the
    unit over the hole, and that is where it now resides. I haven't used
    my stove top since. I don't believe that that unit is available
    anymore on HSN, but it is available on Amazon.com for $99. Not that
    you should buy it, as in 2 1/2 years there may be improvements that
    are implemented on other makes and models.

    There seems to be a complaint about the temperature control on
    induction hobs. Well I also find that it can be a problem, but later,
    in this writing (don't peek!), I'll share with you a TRICK that I use
    that helps. Perhaps you can make use of it too.

    EXPERIMENT 1 [Easy and quick to do]

    Take your largest induction ready frying pan which you have used
    before on your unit and put a 1/4 inch layer of water in it. Place it
    on your induction hob and turn the unit on but immediately set the
    temperature to 150 (or the lowest temperature that your unit allows),
    and observe.

    Notice how the small bubbles begin to quickly form. In particular
    notice where they form perhaps not quite in the center of the pan.
    Notice the shape of the bubble area. Is it a circular disk? A small
    dot? Or are there a number of areas where the bubbling begins to
    happen. Notice how the bubbles are becoming more active and are
    beginning to grow in size, till eventually an area of the bubbles is
    giving off steam and appears to be boiling. Notice how large and
    where that area is (it may not be in the center - Bummer.) Notice the
    water surface in the rest the pan. Have bubbles formed? Is it
    boiling? Watch the progression until the entire bottom of the pan
    contains boiling water. [BACK TO THIS IN A MOMENT]

    The copper wound exciter disk (the induction-cooker element; the wire
    coil) which is just under the surface of the ceramic top may vary in
    size depending upon which induction hob you own. You, as I, don't
    probably know the size of this disk or even if it is correctly
    centered, so by watching the bubble pattern it will give us a valuable
    clue.

    [Here is an exposed photo of a wire coil element:
    http://upload.wikimedia.org/wikipedi...ion_Cooker.JPG

    All elements are not this size. Some elements are composed of
    concentric rings that excite independently based upon settings and pre-
    programmed actions. Your element, if you own an induction hob, is
    probably much smaller in diameter.]

    ---------------------------------------
    BUT WAIT, SOMETHING IS WRONG!
    ---------------------------------------

    In our experiment we were looking at water beginning to boil in our
    frying pan. But we have the temperature set to 150. THAT CAN'T BE,
    for water boils at 212. If our setting is accurate, water shouldn't
    be boiling at all. It should just heat up to 150 and maintain that
    temperature. Perhaps something is wrong with our setting -- not
    really.

    Because the entire bottom of our pan is not heating uniformly there
    are a variety of temperatures across the bottom of our pan. There are
    several reasons for this. First, because of the various coil designs,
    especially in less expensive induction hobs, there are hot spots where
    the heat seems to concentrate at first. You witnessed this yourself
    as you watched the water boil in your pan during the experiment. With
    the real fancy and real expensive units there is a more even heating
    across the bottom. With our units, it takes a little time for the
    entire bottom to heat and the heat to reach the edges of the pan. The
    meantime the hot spot is getting HOTTER AND HOTTER the original
    claim of the uneven heating on the bottom of a pan.

    Secondly, to make it even more complicated, the bases (bottoms) of
    some pans are not perfect. Actually the ferrous material required to
    be in the bottom of our pans and pots, is not the best transmitter of
    heat although it retains heat quite well (example cast iron.)
    Aluminum does much better job of transmitting heat quickly, but it is
    non-ferrous. An aluminum clad iron core pan might be our best bet,
    but I don't have one so I can't test it. Also, some less expensive
    induction ready pots and pans, don't permit they heat to radiate
    evenly.

    We're not through yet. Thirdly, where is the temperature sensor
    located? I would imagine, from the photos I've seen, that it is not
    in the center of the unit and not anywhere where the wire coil is
    located. In fact, it is outside the area of the wire coil looking at
    the area at the edge of the pan (this depends upon the dimensions of
    the wire coil the dimensions of the pan.) As it takes time for the
    heat to reach the extremities of the pan for the thermostat to
    recognize the temperature and start maintaining the correct
    temperature, it is evident that parts of the pan will have exceeded
    the desired temperature Bummer again. [See the typical placement of
    a small temperature sensing device in the previously mentioned
    photograph. Notice that it is outside the area of the wire disk, and
    realize that your pan or pot must be over the sensor for the
    temperature control operation to work properly.]

    This is one reason that your instructions may indicate never to use a
    pan or pot that has under a certain dimension on your induction hob.
    For example, with my hob the directions state not under 5 inches.
    This of course leads me to think that the temperature sensor is
    outside this 5 inch diameter circle. So I actually must be very
    careful in making sure that the pan or pot I use has part of its edge
    over the sensor. Boy it would be nice to know where that center was
    located.

    Since the sensor is somewhere at the edge of the pan and perhaps the
    heat is being developed from the center of the pan outward, it stands
    to reason that it will take time for the heat to reach the edge of the
    pan, especially if you are using cast-iron, and the center of the pan
    will be extremely hot, probably higher than you want to be, until the
    heat reaches the area at the edge of the pan that the sensor is
    reading. Thus you can easily see that the actual temperature control
    is not like you and I would prefer.

    HOW INDUCTION COOKING WORKS - one of the good references on the
    Internet. You may find this of valuable interest.

    http://theinductionsite.com/how-induction-works.shtml


    EXPERIMENT 2 [Easy and quick to do]

    This time, instead of using a temperature setting we are going to use
    the full wattage capability of your induction hob. Again place a
    quarter of an inch of water in a cold frying pan and turn your
    induction hob on to full wattage you are not using temperature
    control at this time. As before, observe. See if the heating area,
    with small bubbles forming, is the same size as the original. Perhaps
    you may discover it covers a larger area. Watch until the entire
    bottom of the pan is producing boiling water. Notice how the pattern
    progressed. Comparison of Experiment 1 and Experiment 2 may produce
    some results that you can utilize when cooking. I would imagine that
    more expensive hobs heat the entire bottom much more quickly and
    evenly but that may not be entirely true.

    EXPERIMENT 3 [Requires an Infrared Thermometer (IR)]

    Well temperature control for the liquidy mass is at lower temperatures
    is pretty easy and may not be as critical, when we want to control the
    temperature for deep fat frying, sauteing, grilling, etc., precise
    temperature control may be more important. For example some oils will
    smoke at a certain temperature. Some food items need to be prepared
    at a medium temperature. We are warned that some cookware with Teflon
    coating should not be exposed to heat about 400. So we really want
    our temperature sensing and control to be accurate.

    This time we're going to take a pan without any water in it and use
    our infrared thermometer to investigate the temperature of the inner
    pan surface as we turn on our hob to maximum wattage. Probably, to
    your surprise, you will find that the temperatures are all over the
    digital display as you point your laser. Get to know what is
    happening as the pan heats up. Try the same experiment with various
    wattage settings. Again do the same with various temperature
    settings. Remember, each time start with a cold pan. You can quickly
    cool your pan under running cold water and then dry it.

    You really don't need a ray gun type of infrared thermometer to do
    this. A simple, small, less expensive hand-held infrared thermometer
    will do the job. Small infrared thermometers are highly useful around
    the house especially in the kitchen. If you don't own one you might
    consider one as a Christmas stocking stuffer. Google 'infrared
    thermometers' either via web or images to check them out.

    MY WORK AROUND TRICK

    Okay, what can we do to help us with better temperature control short
    of purchasing a whiz-bang unit at 6 to 15 times the cost of what we
    now own.

    What I do is similar to the experiments I mentioned above. If I want
    to control the temperature I place the pan on the induction hob with
    some water in it. I turned the hob on to a temperature setting of
    150. I wait until the entire bottom of the pan, from edge to edge,
    has boiling water AND THE WATER STOPS BOILING. This way I'm assured
    that the temperature setting has been activated. I quickly dump the
    water out and return the pan to the hob placing it back on before the
    unit shuts itself off. Now I change the temperature setting, if
    necessary, to what I desire. I believe that the temperature control
    is now more accurate once it has initially started taking control.
    You, of course, will have to experiment for yourself, but I do believe
    you will be pleased with this technique.

    I successfully use these techniques to keep, for example, soups and
    other items warm at 150, and keep Teflon coated pans from exceeding
    that threshold of 400.

    I wrote something similar, in another place:

    If I have a, non-temperature sensitive mass in a pot that I would
    just like to keep warm, I can easily place it on the hob, set the
    temperature to 150, and walk away. I really don't have to worry
    about anything burning if the temperature over shoots a little, as a
    liquid will take care of that, and the induction hob will eventually
    settle down and keep the appropriate temperature of 150.

    In the rare instance where the mass is temperature sensitive
    (because of the chance of burning or coddling), that is, it shouldn't
    be allowed to pass a certain temperature, I take alternate steps. I
    will first put the pot containing only about a quarter of an inch of
    water on the hob and set the desired temperature of 150. I will wait
    until the water stops boiling. This means that the thermostat has
    kicked in. I will then empty the water from the pot and replace the
    contents with the liquidly mass that I just want to keep warm. It is
    best for this liquid is close to 150 to start with. I use either a
    good digital thermometer one infrared thermometer to check the
    temperature. This procedure will relatively sure that the vessel is
    at the proper temperature and that the temperature sensor is working
    before I add the liquidly mass (such as cream of pumpkin soup which
    I don't want to burn). As I said I rarely have to use this technique.

    -----

    FEEL THE FORCE, YOUNG JEDI

    Here is another little trick to be more aware of the temperature
    sensor cycling on and off. On some units, you can actually hear a
    slightly audible click as it cycles on and off. Another way, during
    the cycling process, is to place your hand very gently on the pan or
    pot handle. If you're sensitive enough, you can feel a slight
    vibration when the unit is on which will disappear when the unit
    cycles off. That way you will know that cycling is taking place.
    Although it would be nice if there was some sort of indicator in the
    digital area of the induction hob that would give you this
    information. Mine doesn't have it.

    Good luck with your induction hob cooking.

    Gary Hayman
    http://bit.ly/GarysInfo
    http://bit.ly/GarysHome

  2. #2
    [email protected] Guest

    Default Re: INDUCTION HOB AND TEMPERATURE CONTROL

    On Thu, 2 Dec 2010 06:57:18 -0800 (PST), zydecogary
    <[email protected]> wrote:

    >INDUCTION HOB AND TEMPERATURE CONTROL


    Thanks -- lots of interesting information.

    But if induction hobs were going to be that compliucated to use, I
    wouldn't bother.

    BTW, I started with that same Wolfgang Puck unit. It's still as good
    as anything, except that you can now get 1800 watt units for the same
    price.

    -- Larry

  3. #3
    zydecogary Guest

    Default Re: INDUCTION HOB AND TEMPERATURE CONTROL

    On Dec 5, 3:57*pm, pltrg...@xhost.org wrote:
    > On Thu, 2 Dec 2010 06:57:18 -0800 (PST), zydecogary
    >
    > <zydecog...@gmail.com> wrote:
    > >INDUCTION HOB AND TEMPERATURE CONTROL

    >
    > Thanks -- lots of interesting information.
    >
    > But if induction hobs were going to be that compliucated to use, I
    > wouldn't bother.
    >
    > BTW, I started with that same Wolfgang Puck unit. It's still as good
    > as anything, except that you can now get 1800 watt units for the same
    > price.
    >
    > -- Larry


    I agree -- watching water boil is complicated and challenging. (Tee
    Hee) ;-)

    The water experiments were just a demonstration for those who were
    really unfamiliar with their units and were presented for them to
    better see what was happening as the unit began to operate. In my
    usage, I really have not had any problems with temperature control
    that is not easily managed.

    As you and I know, induction cooking is really simple -- in fact
    easier than a normal stove top; be it gas or electric coil. You set
    the power or the temperature (and a timer if you want) as you turn it
    on and you have all the speed, safety and electricity saving available
    immediately.

    Yes, I have seen the 1800 watt units, and for me, it might be
    overkill. I rarely use the 1400 watts I have available now. I would
    imagine if I were often using a very large stock pot I would sing a
    different tune, But as I am generally cooking for one and use smaller
    containers (except for my great big wok), I don't need the super
    power, that is, unless I am missing something.

    Other than more power for bigger pots, I do wonder what those $600 to
    $1200 single hob units (not built ins) do that our $70 to $120 units
    don't. I have read that some have a feature of auto-adjusting to the
    size of the pot that is placed upon it (activating only that portion
    of the copper coil that would really be used to excite the utensil.)
    With the built in, there are lots of other features such as "place a
    pot anywhere" and "automatic adjustment to shape of pot, pan or large
    griddle under-surface", features that I can admire, but that I don't
    really need.

    It is also interesting to watch the cooking channel and the food
    network and discover the increased use of induction hobs that is
    creeping in -- especially in the shows that visit restaurant kitchens.
    Not too much is made of the fact that induction cooking is going on,
    probably because most of America is in the dark about induction
    cooking and wouldn't know what they are talking about on the show.
    Europe and Asia have taken the lead on this one. Talk about being
    'greener.'

    The same with Sous-vide cooking. Most would say "What ?????????" Yet
    some of the finest restaurants (and even the not so 'finest') use Sous-
    vide for some of their food preparation. This evening I prepared some
    chicken using the Sous-vide method. I am experimenting with that too.
    Next I will use it for various fish.

    http://en.wikipedia.org/wiki/Sous-vide

    http://amath.colorado.edu/~baldwind/sous-vide.html

    Ain't cooking FUN! Tomorrow -- Shabu-Shabu.

    Gary

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