Cast iron and powersettings on induction cooktop.

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Just to pick up on this point: my Bosch definitely isn't linear. It has 1-9 and boost. You'd expect 9 to be 90% power, 8 to be 80%...

Testing both with a power meter and by timing water heating up, 9 is about 60% of boost. 7 is about 25%. Everything below that is just fine gradations. It actually makes sense; it allows fine control of a simmer, whereas when I want boost I just want all the power. But it took me a while to get used to it!
Yeah, this is one of the things that's *really* hard to explain to people using standalone PICs in the U.S., especially when they're trying to compare power settings with those on full-size induction hobs. I once got into a long back-and-forth with someone about how I had to use a power setting of 6-7 on my Neff to cook (American-style) pancakes properly, and he insisted that any setting above a 4/10 on his PIC would produce the equivalent of "cajun-style" pancakes, i.e., blackened beyond recognition. He couldn't believe a setting of 6-7 on mine wouldn't do the same.

Oh, and then there's the issue of steady power output vs oscillating power output. Most of the PICs cycle on/off from full power to no power based on the chosen power setting. Meanwhile, most full-size cooktops just reduce power output and keep it linear, kind of like Panasonic microwaves with inverters.
 
That makes sense for Bosch induction though since the linked element turns off when you use boost.
Do you mean the weird linking-up-different-plates function? I don't find that at all reliable and never use it...

My four plates each have two halves, and all but the biggest pans work quite happily on one half. I do note that you can't use boost on two adjacent plates; it switches you down to 9 on both if you try it.

Oh, and then there's the issue of steady power output vs oscillating power output. Most of the PICs cycle on/off from full power to no power based on the chosen power setting. Meanwhile, most full-size cooktops just reduce power output and keep it linear, kind of like Panasonic microwaves with inverters.

Mine stays constantly on with varying power output down to 6. Below that it pulses.
 
Mine stays constantly on with varying power output down to 6. Below that it pulses.
Really? If, for instance, you have a pot full of simmering liquid, will you see it simmer, then fall below a simmer, and then back up again? Or are the pulses so quick that it's fairly steady state?
 
Really? If, for instance, you have a pot full of simmering liquid, will you see it simmer, then fall below a simmer, and then back up again? Or are the pulses so quick that it's fairly steady state?
It's fairly quick. Setting 5 is something like three seconds on / one second off / three seconds on etc. As you go lower down, the on periods get a little shorter but the off periods aren't any longer. Setting 1 is something like on for half a second / off for a second.

The lowest I've actually used is 2, to get stock to a barely tremulous simmer. Rice usually goes on 3.5. In both cases it's fine, and you certainly don't notice the effect of the pulsing in the liquid - you just hear it faintly.
 
Someday one of these mfg's will come up with copper core mild steel. Unless this is out there already? I still cook on propane, but right now, only because I'm off grid and only have 14kwh of storage to contend with, which isn't too luxurious around the solstice. I do wish to incorporate induction at some point. For ease of cleaning the surface at the very least. Still would need an auxilliary propane burner for my large j wok though! :)

Do any of the higher end induction systems NOT pulse to lower effective power?
 
Miele CS7612FL preliminary results. Will repeat with better sampling at the low end.

It stops PWMing at level 5. The steps go 5 6 7 8 9 Boost. Apparently there is a second level of Boost which I will achieve in the next run.

IMG_2355.png
 
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Just got a new induction range and have been relearning everything the past few days. Oddly enough it seems to cook significantly less hot than my old electric/glass element. I trained myself to not really use above 6/10 on the old range. The induction on my Frigidaire is pretty linear and makes sense. The touch controls already piss me off though, fine until you spill a droplet of water and it auto shuts everything off.

I need to do some more testing but it may boil water faster than my electric kettle...which is neat.
 
Induction can be faster than a kettle (by virtue of pumping more energy in there) but in energy efficiency just about any cheap electric kettle will still win.
 
I think there is one more factor to consider. It is not only the intensity of the heat. I use a tetsubin really (handmade cast iron water kettle - good ones are quite pricey). Tetsubins are used on coal fires, which give very intense heat, but they do so evenly!

Aand that contributes to the difficulty with induction - it doesn't heat up the material uniformly, but has some concentrated hot spots. Sandwiched pots with conductive materials like copper or aluminium will distribute the heat very quickly. Also, they are more elastic and can handle the physical stress from irregular expansion.
But since cast iron is a poor conductor of heat + is not elastic, the heat in hot spots will distribute slower and have more risk of cracking due to their rigidity. That is why I use cast iron cookplates for my Tetsubin.

For example, here are some infrared photoes of pans on induction:

Gear-30sec-HI.jpg


From left to right: cast-iron, T-fal, and Cuisinart carbon-steel after 30 seconds on a high induction stove setting. Note the hot spot in the middle of the T-fal.
source An Unfussy, Affordable Nonstick Pan That Works With Induction

990tdrk02hrz.jpg


source:

You can see how much colder some areas are? This will increase the structural stress many times. I saw other photos like that with even more concentrated hot spots on cast iron pots. You might want to check your stove for that. Maybe modern, high-quality stoves have more even heating patterns?

If not, you could use a diffusor. They're cheap and will pre-distribute the concentrated heat for your cast iron. This should reduce the risk of strong heat significantly.
 
Miele CS7612FL preliminary results. Will repeat with better sampling at the low end.

It stops PWMing at level 5. The steps go 5 6 7 8 9 Boost. Apparently there is a second level of Boost which I will achieve in the next run.

View attachment 290513
How quick is the modulation ? Does it cause water to go boil-still-boil-still ?
 
How quick is the modulation ? Does it cause water to go boil-still-boil-still ?
Let me get back to you about that. Tonight I had a heavy Staub making stock so the mass got in the way of answering that question.

I did get an updated graph, the consumption may be higher because the pot is bigger.

We start at Boost 2, then Boost 1, then 9 8 7 6 etc. At 4 and below, I suspect it is cycling between number of active subcoils so the wattage doesn’t go to zero until heat level 1 and keep-warm.
IMG_2919.png
 
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