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Rasmus

Ideal stove control?

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I am currently working with an induction stove, and I wonder what scale to use for the controls.

Traditionally it would be a relative scale representing the effect, e.g. 1-6, and the user behavior would be to first set the stove to 6 - e.g. to boil up water - and then turn down to 2 - to keep it simmering.

But given that we can detect the temperature and use a so called PID algorithm to maintain the temperature, we can let users set a temperature and the stove will then keep it.

So my question to this forum is what an ideal scale would be? Would people want to be able to set the temperature of the pot/pan or do they still prefer to just set the relative effect? How many steps should the scale have?

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I have no personal input for you and this may go beyond what you are doing but for another perspective, you may want to listen to Episode 358 of Dave Arnold's Cooking Issues podcast where a vision challenged user called in looking for an induction unit with a knob rather than a membrane touch pad, or some other way to get positive, non-visual, feedback from adjustments.  It's not a specific need that I have but I can imagine it being useful for many people.

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22 minutes ago, Rasmus said:

But given that we can detect the temperature and use a so called PID algorithm to maintain the temperature, we can let users set a temperature and the stove will then keep it.

So my question to this forum is what an ideal scale would be? Would people want to be able to set the temperature of the pot/pan or do they still prefer to just set the relative effect? How many steps should the scale have?

 

You are asking two types of question here:  (1) Arbitrary power settings or temperature? and (2) What granularity?

 

Whatever your preference, the arbitrary numerical settings are here to stay.  This is for the simple reasons that cooks are familiar with power settings.  How many cookbooks and online recipes are written that way?  The vast majority.  Temperature settings on most induction appliances are horribly inaccurate, too.  Where temp settings are useful is where you know a specific pan temperature you want/need (and/or you need to repeat it).  But typically you gain that knowledge only from experience with your specific appliance heating your specific cookware.  Some models will preheat to the set temperature faster than you can do it manually.

 

Do you really have PID capability in your stove?

 

As far as granularity goes, IMO, the more the better.  I have an induction appliance with 100 power settings, which I think should be enough.  

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On 3/25/2019 at 4:52 PM, boilsover said:

 

You are asking two types of question here:  (1) Arbitrary power settings or temperature? and (2) What granularity?

 

Whatever your preference, the arbitrary numerical settings are here to stay.  This is for the simple reasons that cooks are familiar with power settings.  How many cookbooks and online recipes are written that way?  The vast majority.  Temperature settings on most induction appliances are horribly inaccurate, too.  Where temp settings are useful is where you know a specific pan temperature you want/need (and/or you need to repeat it).  But typically you gain that knowledge only from experience with your specific appliance heating your specific cookware.  Some models will preheat to the set temperature faster than you can do it manually.

 

Do you really have PID capability in your stove?

 

As far as granularity goes, IMO, the more the better.  I have an induction appliance with 100 power settings, which I think should be enough.  

 

Yes, I have PID control and it is quite accurate. Many if not most appliances are poorly made why people need to learn to know their flaws. But correctly designed, using digital sensors etc, that isn't necessary. I suppose you are right though that people are used to the power setting, so it may continue for that reason.

100 scale is interesting.

Thanks!

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On 3/25/2019 at 4:34 PM, blue_dolphin said:

I have no personal input for you and this may go beyond what you are doing but for another perspective, you may want to listen to Episode 358 of Dave Arnold's Cooking Issues podcast where a vision challenged user called in looking for an induction unit with a knob rather than a membrane touch pad, or some other way to get positive, non-visual, feedback from adjustments.  It's not a specific need that I have but I can imagine it being useful for many people.

Ok, thanks. I will listen to that.

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11 hours ago, Rasmus said:

Yes, I have PID control and it is quite accurate.

 

Interesting.  What are you using for thermocouple(s)?

 

There's an emerging fetish here for the level of control PID is capable of, basically an offshoot of the sous vide craze.  Past a certain point, though, it is somewhat illusory, at least in dry cooking.  E.g., the temps are usually measured in one spot (usually at the center bottom for built-in thermocouples), and there can be 10s of degrees of Delta Ts at the periphery.   An argument can be made that using your senses and measuring the internal food temperature is all you really need.  

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Posted (edited)

I own a Vollrath Mirage Pro which has 100 power levels and allows you to set the temperature control in 5 degree increments. I have owned cheap units that had 10 or 15 power settings, and while they were okay for some things, the lack of a finely graded temperature control made them awful for any task where semi-accurate temperature control is desired. This happens more often than you might expect. The biggest bugaboo in this department is maintaining a simmer (and, by extension, maintaining pressure in a stovetop pressure cooker). If all you have is 10 settings, your ideal temperature might be somewhere between 1 and 2, or between 3 and 4... or whatever. If you select the low setting, the bubbles will die down completely; if you select the higher number, the pot will reach a full-on rolling boil. If all you have is a binary between "no bubbles" and "rolling boil," you're going to have a bad time.

Another place that having fine control is useful is at the lower end of the temperature spectrum, like for tempering chocolate or cooking eggs. Vollrath makes a big deal about the Mirage's ability to melt chocolate at like 85F (or whatever). I don't do pastry/chocolate, so I can't comment there... but I do appreciate the ability to dial down my pot or pan to a very low setting for various applications. And while the temperature control (versus the 100 level power settings) on the Vollrath isn't the most precise, it's usefully spot on in the magic egg-cookery range of 60-70C. At 60C with a very thick (and well pre-heated) pan, eggs will just barely cook -- you could walk away for 15 minutes and they'd be slightly thickened from the base, but not much else. At 65C, they thicken and cook very gently -- give them a stir every three minutes or so over thirty minutes, and you'll have perfect custardy bain marie style eggs. At 70C the eggs cook much more quickly, but still yield a nice slow scrambled style (just with a much tighter curd).

At any rate, having 100 power levels is fantastic. But it would be less fantastic if these weren't tied to a hardware knob (or rotary encoder, in this case). Membrane switches on induction are a freaking nightmare. Do you want to poke at a panel 100 times to adjust the temperature? Or sit there and wait while you hold your finger down on the button? It's awful. 100 levels of power are useless if they're locked behind switches. You need a knob so you can crank things up or throttle them back quickly and easily and without having to look at a display while you fiddle with membranes.

Apart from having a highly granular access to the unit's maximum wattage via some sort of knob/dial, the other important thing to develop is accurate temperature control. 1-100 is great for some applications, actual temperature control is better in others The units to beat with respect to temperature control are the Polyscience/Breville Control Freak and the burners from Hestan. Having a temperature sensor in the cooktop as well as a wirelessly connected temperature probe seems like the way to go there. That could be an upgrade/upsell, because not everyone would be interested. But there is no other induction unit under $1000 (basically) that has 100 temperature levels apart from the Mirage Pro, and the Mirage Pro is targeted exclusively at commercial audiences. Home consumer use invalidates the warranty, which is stupid.

So the market is wide open for a quality induction burner with a lot of control at a reasonable price for a home consumer market. 

Wide open.
The world doesn't need another garbage induction hob. What it needs is something that can sell for $200-ish with a big induction coil, 100 power settings, a knob, and a $50 bluetooth temperature probe that works in conjunction with a temp sensor in the base to deliver extremely stable PID-based temperature control.

Shoot for that, or something very close to that. Anything else is a waste of your time (and everyone else's).


Edited by btbyrd (log)
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17 hours ago, boilsover said:

 

Interesting.  What are you using for thermocouple(s)?

 

There's an emerging fetish here for the level of control PID is capable of, basically an offshoot of the sous vide craze.  Past a certain point, though, it is somewhat illusory, at least in dry cooking.  E.g., the temps are usually measured in one spot (usually at the center bottom for built-in thermocouples), and there can be 10s of degrees of Delta Ts at the periphery.   An argument can be made that using your senses and measuring the internal food temperature is all you really need.  

It's actually a rather complex cooking machine where we use convection heat, steam, grill and induction. www.varm.io. This is an earlier version.

We have a "Cvap" effect, where we can do low temperature steam, which in many ways is better than sous vide.

But for hot air we have first simulated the air streams and then used thermal imaging to place the TCs. We had to design our own convection heat system, as the standard systems weren't very efficient.

For the induction TC we place it at the bottom to measure the pot temperature. Like a rice cooker. It's pretty good, but we are trying to figure out how the bottom temperature of the pot relates to the top, i.e. where the food  is.

We also have IR sensors so we could read the food surface or pot surface, if empty.

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100 power settings seems like a good number. Would 50 be enough? Perhaps, but that would have to be tested, I guess. As @btbyrd says, 10 are far too few.

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7 hours ago, btbyrd said:

I own a Vollrath Mirage Pro which has 100 power levels and allows you to set the temperature control in 5 degree increments. I have owned cheap units that had 10 or 15 power settings, and while they were okay for some things, the lack of a finely graded temperature control made them awful for any task where semi-accurate temperature control is desired. This happens more often than you might expect. The biggest bugaboo in this department is maintaining a simmer (and, by extension, maintaining pressure in a stovetop pressure cooker). If all you have is 10 settings, your ideal temperature might be somewhere between 1 and 2, or between 3 and 4... or whatever. If you select the low setting, the bubbles will die down completely; if you select the higher number, the pot will reach a full-on rolling boil. If all you have is a binary between "no bubbles" and "rolling boil," you're going to have a bad time.

Another place that having fine control is useful is at the lower end of the temperature spectrum, like for tempering chocolate or cooking eggs. Vollrath makes a big deal about the Mirage's ability to melt chocolate at like 85F (or whatever). I don't do pastry/chocolate, so I can't comment there... but I do appreciate the ability to dial down my pot or pan to a very low setting for various applications. And while the temperature control (versus the 100 level power settings) on the Vollrath isn't the most precise, it's usefully spot on in the magic egg-cookery range of 60-70C. At 60C with a very thick (and well pre-heated) pan, eggs will just barely cook -- you could walk away for 15 minutes and they'd be slightly thickened from the base, but not much else. At 65C, they thicken and cook very gently -- give them a stir every three minutes or so over thirty minutes, and you'll have perfect custardy bain marie style eggs. At 70C the eggs cook much more quickly, but still yield a nice slow scrambled style (just with a much tighter curd).

At any rate, having 100 power levels is fantastic. But it would be less fantastic if these weren't tied to a hardware knob (or rotary encoder, in this case). Membrane switches on induction are a freaking nightmare. Do you want to poke at a panel 100 times to adjust the temperature? Or sit there and wait while you hold your finger down on the button? It's awful. 100 levels of power are useless if they're locked behind switches. You need a knob so you can crank things up or throttle them back quickly and easily and without having to look at a display while you fiddle with membranes.

Apart from having a highly granular access to the unit's maximum wattage via some sort of knob/dial, the other important thing to develop is accurate temperature control. 1-100 is great for some applications, actual temperature control is better in others The units to beat with respect to temperature control are the Polyscience/Breville Control Freak and the burners from Hestan. Having a temperature sensor in the cooktop as well as a wirelessly connected temperature probe seems like the way to go there. That could be an upgrade/upsell, because not everyone would be interested. But there is no other induction unit under $1000 (basically) that has 100 temperature levels apart from the Mirage Pro, and the Mirage Pro is targeted exclusively at commercial audiences. Home consumer use invalidates the warranty, which is stupid.

So the market is wide open for a quality induction burner with a lot of control at a reasonable price for a home consumer market. 

Wide open.
The world doesn't need another garbage induction hob. What it needs is something that can sell for $200-ish with a big induction coil, 100 power settings, a knob, and a $50 bluetooth temperature probe that works in conjunction with a temp sensor in the base to deliver extremely stable PID-based temperature control.

Shoot for that, or something very close to that. Anything else is a waste of your time (and everyone else's).

 

Interesting. I will look at that.

We will have a bluetooth probe, and also IR sensors to read the temperature from above.

For the scale the balance is between features for "power users" and ease of use for regular people. I suppose we could use a volume control style.

We have gotten rid of the knob, though we had one in an earlier prototype. I was quite reluctant to do that as I also hate those touch sensors, but we have a massive control screen (17 inches) with touch, so the thinking is that we can build a UI that is easy to use for wide range settings. Currently we are looking at a Timer type setting, like you have in the phone Timer. Rollers, to move up and down. And then combine that with some bookmarked settings.

E.g. you could potentially save a shortcut to reach the temperature for melting chocolate.

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Any idea what it will cost?

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19 hours ago, gfweb said:

Any idea what it will cost?

Not yet... We are doing price studies to understand how best to price it.

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You're likely going to end up needing both "manual" power and "automatic" temperature settings, like many modern automotive AC interfaces.

 

Unlike baking, very few recipes and traditions for stovetop cooking mention the actual temperature since there's such an intentionally high contrast between the cooking temp and the target interior food temp. But as the other folks mentioned, there still is a lot of utility to the newer temperature-based model for low-temperature cooking, holding simmers, or making sure to avoid smoke points with your fats.

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A couple of things. Most induction cooktops need much finer temperature control IMO. If you really have an accurate PID control, you could use it for sous vide and would want temperature control to about 0.5 C up to 100 C. After that most people probably wouldn't mind relative control but I think they could get used to setting temperatures, especially if it was fast to make big jumps but maybe included a find control, too. The other place that absolute temperature would be great is for deep frying.

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You get use to precise control. I own two Control Freaks. Yes there’s a wide a range of temps that work but there’s a noticeable difference in quality even at the higher temps. 

 

This morning I’m making breakfast sausage. I use 300 to caramelize the sugars while cooking the protein. Big difference in flavour than when I use to eyeball it. You kind of get a feel for temps after a while. And for newbies Breville automatically label temperature ranges as your dialing in (very low, low, simmer, medium, medium high, high, seas —- if I recall correctly)

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241

On 3/29/2019 at 3:30 AM, Rasmus said:

Not yet... We are doing price studies to understand how best to price it.

When determining this price point are you looking to price the device for maximum market penetration or maximum return on investment or somewhere in between? At least in my mind the middle-of-the-road choice is probably the best. I obviously would love to see you price the device for maximum market penetration because it would be cheaper to consumers but that route would lean to rapid failure if the market didn't appreciate the capabilities of the device. Maximizing return on investment is I have is a good thing but it's certainly going to minimize the market available to you.

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On 3/31/2019 at 12:32 AM, MSRadell said:

241

When determining this price point are you looking to price the device for maximum market penetration or maximum return on investment or somewhere in between? At least in my mind the middle-of-the-road choice is probably the best. I obviously would love to see you price the device for maximum market penetration because it would be cheaper to consumers but that route would lean to rapid failure if the market didn't appreciate the capabilities of the device. Maximizing return on investment is I have is a good thing but it's certainly going to minimize the market available to you.

Maximum market penetration, as we will make our money in other ways. :)

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Most ovens in Mexico have no thermostat.  The "ideal stove control" is a wooden spoon inserted in the oven door jamb when the oven overheats.

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