valeriojoann: First, as noted above, the Silpat is not the recommended item for pan support. Instead, non-reinforced silicon sheet is used to make small circular pads (squares, triangles, and other geometric shapes are also possible). Three pads arranged in a triangular array are used because three non-colinear points define a
plane. (Any residual pan wobble has to be due to some other part of the pan
touching the cooktop.)

These provide the following advantages:

• Separation of the pan from the cooktop surface, reducing potential scratching
• Separation of the pan from the cooktop surface, reducing heat transfer back to the surface; a cooler surface may reduce stress on the electronics below the surface and is less of a hazard to a misplaced hand

Disadvantages include

• Having to buy the silicone sheet
• Having to cut out shapes
• Storing the pads somewhere handy

When the pan is large and rectangular, such as a griddle, use of four pads may be helpful when pressure on the pan could cause it to tilt.

kas

eliasgrace: You can distinguish us in the future by recalling that the name Kenji means a number of things, take you pick from among those at https://en.wikipedia.org/wiki/Kenji_%28given_name%29 and the handle kaseki means fossil. :)

I have been attempting to do my due diligence regarding the most recent launch of the Miele 30 inch Induction Cooktop... That said all this attention to the "liners" you are using/creating under your induction ready pots and pans sounds like a lot of "maintenance". What will happen if I skip that part? Thanks

As far as I'm concerned - nothing. I've only had mine for 9 months to be fair, but lots of cast iron use and no scratches so far. Probably a little more likely to scratch overall, but... I can't get too worked up about it, and I've had 9 months so far scratch free without having to purchase or deal with liners.

Iharpie: thanks for your input.

everyone: Is the scratch issue the only reason for the liners? Is there some thought that the liners will lengthen the life of the "electronics"?

thanks!

For me, just scratch-prevention

I don't use them. No problems so far. I wipe as I go with a moist sponge.

I only use padding when using cookware that its bottom surface is not so smooth.

I don't have any cookware that isn't smooth on the bottom and don't use pads. They can't hurt. I do use newsprint paper (the kind without the ink, saved from packaging) under my pot when frying.

I use a paper towel when I know I'm going to have splatter effects. Others I've heard use newspaper. As long as you stay under *450 you're fine. When I used to use a skillet for bacon, I didn't get much above *350.

Weedmeister: Because I'm still in the due diligence stage, I had no idea you

could tell the specific temperature if the hob. How is that possible?

thanks a million!

Pillog: Where exactly do you find ink less newspaper? Thanks!

You can use newspaper--since they went to the soy ink, which is better for the environment, but makes me sneeze and transfers easily, I've gone to using plain newsprint paper and get the newspaper electronically. I often enough have some kind of new delicate thing or other to get a lot of newsprint packaging paper, hardly used, and I fold it up and stash it in the kitchen. You can buy it at any packing or paper store, and probably big box and stationery stores. There's also newsprint paper for printing on, in sheets as well as rolls, and newsprint art paper, prized for being cheap, porous and having monodirectional tearing. You can get those at paper stores if nowhere else. If there's a small newspaper in your area, with old fashioned presses, you might also be able to get an end from them. A roll end should last you a lifetime.

Thanks again for the input guys...Plllog thanks for the overheating advice, and Kas, will try to remember "fossil" from now on!

So the latest is that now I am considering a 30" Miele induction and a 24" (4 burner) Bluestar. Will probably need a 66" hood...oh boy. Went to the Miele store and saw firsthand that the new layout of the 36" does not allow for all of my big pots and pans. The 42", however, does have ample room for three large pots but again, I'm hesitant to purchase something that may very well be discontinued due to awkward size.

Is 1200 CFM/66" x 27" depth hood enough ventilation for 24" gas plus 30" induction? This is assuming 4-6 inches in between cooktops.

I think I'm going to have to write a standard monologue on this topic one of these days. En brief:

Hood entrance apertures should (except where constrained by walls and cabinets) extend past the locus of all likely pan bases by about 10 degrees half angle. Typically, a rougher rule of thumb of the hood OD extending three inches past the cooktop edges is adopted.

Simultaneously for dual cooktops, be sure that your cabinet design will support whatever cooktop-to-cooktop spacing you intend to use.

Hood depth front to back should meet the ten-degree requirement also, keeping in mind that many cooktops have controls on the front edge where hot pan bases shouldn't be located.

Once the hood entrance aperture is picked, calculate its area in square feet. Multiply by 135 CFM/sq. ft. to find a reasonable blower rated flow rate. (Actual flow rate in many typical conditions will be closer to the desired 90 CFM per square foot, or 90 ft/min average air velocity at the aperture or about twice that at the baffle gaps, matching the velocity of the uprising and expanding cooking plume).

Unless your MUA pressure loss is known to be low, you may wish to go higher in rated blower flow rate. My Wolf Pro Island Hood (about the dimensions you listed) is connected to a 1500 CFM rated blower, and I expect the actual flow rate is about 900 CFM over its roughly 10 square feet of aperture.

kas

On silicone pads: An advantage of three small pads over larger sheets of silicone, newsprint, parchment, etc., is that the hob alignment markings can still be seen for pan centering.

All: I currently have an electric cooktop with a glass top. There is no problem

keeping it clean if I end up spilling something on it while I am cooking. I simply use one of those glass cooktop cleaners which are a creamy consistency.

So what is the big deal with accidentally spilling something on your Miele

Induction Cooktop? What am I missing here? Is it not easy to clean?

Thanks a million!

Kas, the newsprint is for spatter cleanup, which your pads don't do a lot for. :)

Valeriojoann, there is no problem with spilling on an induction cooktop, except for crystals of salt or sugar, which, when scooted around under a pot being moved can make a damaging (rather than cosmetic) scratch. But that must be the same for radiant, too, right? Those should be wiped up right away, and that's easy to do on induction because other than right under the pot, the cooktop doesn't get hot, and even so, I've been known to lift a pot and wipe under it while it's hot. The thing is to be careful not to steam your fingers if you're wiping up damp where it's hot, because that can burn. Use a half dry sponge, or a dry towel on top of the wet part, and you're fine.

The trick with induction is that you can wipe up while you cook. You can use your cooktop cleaner if you make a big baked on mess, which can happen if you're juggling a large number of full pots and just don't have the time or attention to wipe up while you cook. Or you can just do the hot water soaked towel thing to loosen the crud and wipe it up with a sponge. The cleaning should be easier than on your hotter radiant cooktop.

Because it's so easy, we get lazy and want it to be pristine always. Frying should happen at a lower temperature than paper burns (only a few fats will accept 450° F, and even they aren't happy about it--375° is the norm), and the space between the pot and the glass never gets as hot as the oil, so you can put down paper with impunity and throw away the spatter, instead of cleaning it. That's why I like to reuse packing paper, since it's going to be thrown away in the end. There's usually only one small place, which gets dripped on more than spattered, which is too oily to put in the recycling, anyway, and if you compost at home, I think you can put the newsprint right in.

Val: my induction unit has temperature control as an option (CookTek). I don't use it that much because it isn't that accurate. The sensor is under the glass, not in the pan. But it does give me a coarse idea of what is going on. If I want a slow simmer, I can set the temp to *165 - *175 or '1' (out of 10).

weedmeister: Which Miele Induction cooktop has CookTek?

thanks

CookTek is a different brand altogether. Their products are mainly for commercial kitchen. http://www.cooktek.com

Kas -- thanks for the vent hood tutorial, yet again : ). So according to your equation, if I have a 63 to 66" hood, I should probably get a 1500 cfm blower. Would it be the end of the world if I stuck with the 1200 cfm (for 4 Bluestar gas burners and 30" induction)? I don't think I would ever really use all the gas burners and the induction at the same time. DH is already going bonkers trying to figure out the MUA for 1200 CFM...if I told him I needed to up it to 1500, he would probably just throw in the towel!

Also, was talking to a potential countertop fabricator and he said that he would only need 3" in between the two cooktops. Does this sound way too narrow to be safe? And could this potentially violate code?

I'm not Kas, but I will say that code is a tricky thing and little details like that may or may not be regulated locally. I have a 15" gas and 24" induction, with a tile counter, and had to have 4". With a sturdy, rather than brittle, stone, like soapstone, or maybe quartz, 3" sounds reasonable to me, especially if there's a plywood underlayment. Remember all those heavy pots you want to cook, though! You'll want all that holding them up!

I would be most concerned with stress fractures over time with heavy pots and pans. With a proper cabinet foundation, most concern for this disappears unless local building code or the specific counter material has restrictions.

eliasgrace: Because we can't allocate the air flow to just the part of the hood where the effluent plume rises to, even if it is a single burner, we have to have the air velocity high enough for containment over the entire baffle or mesh filter area. Of course, imperfect containment of only one burner will be less annoying than imperfect containment of many burners operating at once. There are undoubtedly various second order effects that will occur in the complex fluid dynamics of multiple burner operation that we can't affordably analyze. As may be seen in Figure 4, page 9 of Greenheck's guide (http://www.greenheck.com/media/pdf/otherinfo/KVSApplDesign_catalog.pdf), there is some variability in requirements due to both cooking conditions and even rules of thumb. Note that the values in this table are actual achieved flow rate or velocity over the aperture of a rather large commercial hood, and not rated zero static pressure blower flow rate applied to a more modest residential hood.

That said, without a thorough analysis of all the pressure losses, fan curves, etc., recommendations from me should be treated as suggestions for adequate capture and containment; no one will want (aesthetically, acoustically, or economically) to install a ventilation system that is perfect at capture and containment of every possible cooking mode's effluent. In other words, 1200 CFM rated zero static pressure flow rate may be adequate for you, particularly if you don't griddle or wok.

Note that the actual MUA system flow rate has to be based on the actual achieved vent hood flow rate, minus house leakage at the interior pressure that one is aiming the MUA toward achieving, which depends on code or risk of combustion appliance back-drafting. For example, a 1200 CFM blower pulling an actual 800 CFM, say, needs 800 CFM of MUA, of which perhaps 200 CFM is supplied by the house's leakage, depending on how tight the house is. The challenge, if combustion appliances are present, is supplying the remaining 600 or whatever CFM at a pressure drop of only 0.03 inches w.c. A blown MUA system such as Fantech is now supplying may be needed. Alternatively, a passive MUA system (with higher intrinsic pressure loss) can work if there are no combustion appliances and only lip service MUA is needed to meet code, or if the combustion appliances have independent (of the kitchen air) MUA and thus are not a carbon monoxide hazard.

kas

Question - I am going to install the Gaggenau 36" induction that has the flexible "zones" that allow for up to 4 pots of varying sizes (the CX491).

Since this will take up to 4 pans, and adjust for the sizes, is this layout actually a more functional option for you since you can put them closer together and use whatever shape makes sense? I looked at the Meile and it kinda seems that there is still a reasonable amount of dead space in that 24"

I too am coming from a 6 burner with a griddle 48" cooktop - but realizing that the burners are fixed whether I am using a butter warmer or a stockpot, having the variable "source" seemed like the right idea. And I also looked at how I use the cooktop and it's rare for me to have over 3 pots going.

Just a thought.

Wish my house would get done so I could be helpful on the "how does it perform" aspect... LOL

Kas -- thank you! I will look into Fantech MUA. For me, the MUA is the most intimidating part of the whole kitchen design...

Plllog/Sidpost -- I will be doing a carrara marble top. Is this considered a sturdy stone? Does the 24" rangetop and 30" cooktop (both in 30" cabinets) with 3 inches of carrara in between sound reasonable?

Jannicone -- thanks for your input :). We did actually look into the Gagg full surface but ultimately decided that it wasn't enough space for us. I could only fit two of my big pots/pans on it with room for maybe a small saucepan.

Marble is generally porous and soft. Properly supported and sealed it should serve you well.

Personally, I use very dense Granite in my kitchens for functional reasons AND I like the looks. Personal aesthetics aside, Marble is a good stone when properly prepared and properly supported.

Rome is a good test case for what happens to Marble and other stones after long term wear and tear from bare feet and hands on various steps and objects. The wear patterns have a beauty all their own.

If there is any doubt about strength, it won't hurt, so long as cooling air paths to the induction unit are not blocked, to support the stone with beams (mini hardwood joists or appropriate metal section shapes) carrying [helping carry] cooktop loads to the cabinet sides. Be sure everything is flat (planar) before the stone shows up.

kas

Marble cracks easily, especially along veins. Carrara has fewer but there are still more you can't see, and a crystal structure that's easier to break when it's cut thin. Listen to your fabricator, but, that said, I'd go with 3/4" plywood underneath, and a compound edge to hide it. That will support both the marble and the cooktops. I'd also go for the full 4" if not 5 or 6, but if you need to shave it and your fabricator says it's okay, then it probably is. Be aware that oil makes marks on marble, as does acid (vinegar, wine, tomato, lemon, blueberry juice (that one I know from experience), as do colors. Sealing helps a lot, of course, but you might also want to get in the habit of wiping up spatter from the induction and marble both, while you're cooking. The oil marks will evaporate. A poultice can lift color. Etching is forever, though you can polish it out a bit. Or you could do a soapstone feature area for the cooking zone. :)

ETA: By "easily", I meant for stone. It wouldn't be an issue if it weren't such a narrow piece at a place with so much variable weight and stress.

3cm dense sealed Granite for me for the reasons mentioned above. It has served me well with grease splatters, sloppy handling of soup, stew, and tomato sauce. Great cabinet prep and support is important too.

Porous Marble and a red wine spill is a disaster that is almost unrecoverable in most cases. Proper prep, sealing and, clean up will go a long way to avoiding this problem.

Well, I've long had my heart set on the marble so I'm going to stick with that : ). But thank you all for the advice on countertop supports!

Hood question for you guys...The cooking surfaces combined will be 24"+3"+30" = 57". I am thinking a 63" hood will suffice? I'm thinking of customing the hood to be 63" wide by 27" deep and 15" high. Here is the link to the hood:

http://prizerhoods.com/hood-details/?h=4

The hood is typically 18" tall but I am customizing it to be 15" tall purely for aesthetics. It will be set at 30" above countertop (which I'm assuming is the ideal height for max effectiveness?). The reduction in height of the actual hood (15" vs 18") will have no bearing on hood effectiveness, correct? I can keep it at 18" tall if there is any functional benefit....

Marble is very pretty so, no worries there. Proper prep and reasonable care removes all concern for normal wear and tear. Just like Granite, some is weaker and more porous than other slabs so, there really are no absolutes for one or the other besides good prep for installation.

Think of it like the retiree who dreams of a classic fastback Mustang of his or her youth versus me who dreams not of the car of my youth but a modern German import. In my case if I want nostalgia, there are old pickups, wheat trucks, and tractors to occupy me :-D

When it's time for a nice drive, http://www.porsche.com/usa/ is what I see in my future. The new Macan should not be missed if you are shopping for a Lexus, BMW or, M-B SUV. ;-)

Me, I'm currently eyeing Granite slabs in Shreveport, LA.

Depends. Is this a remote blower system or are the blowers in the hood?

The ideal hood shape would be like a trumpet with the loud end down. This would provide the lowest internal transition pressure loss. Fortunately for aesthetic design, not to mention practical baffle shapes, transition pressure loss in the hood is probably at least fourth down the list of pressure loss sources, so most shapes will be OK. However, the lower the up-down thickness of the hood, the less easily the air can be made to have uniform flow rate over all the baffles. Meshes can be made with higher loss, and this will help make the flow more uniform, but it will be at the cost of the flow rate one wants.

The ideal height of a hood above the cooktop depends on a lot of factors. Commercial hoods are typically set at seven feet above the floor, providing room for a variety of cook heights, a shelf, and maybe a salamander. They have much more cooktop overlap to compensate, and much more total air flow rate to function at that size. Thirty inches is probably as low as one would want to go, and the viability of this height for you, head impact and sight-line-wise, should be checked by a side-view stick diagram. Functionality of sufficient clearance to work is a higher priority than perfect plume edge capture.

In any case, the real hood size requirement is driven by capture of effluent plumes that expand in diameter as they rise. The nominal practical (cost vs. aesthetics vs. diminishing performance) capture angle is around 10 degrees to capture most of the plume, and this is measured by finding the arc tangent of the ratio of (a) offset -- horizontal hot pan edge distance to the inside edge of the hood aperture, to (b), the height from the pan base to the hood aperture entrance.

When we nominally say hood exterior size three inches larger than cooktop size all around (except where there is a wall), what we really want is hood interior size a number of inches larger than the extent of hot pan bases by some value that is affordable. Ten degrees at 30 inches is an offset of 5.3 inches. This means that for the three-inch "outside" rule to meet the 10-degree "inside" rule, the hood sides need to be thin and the pan edge somewhat removed from the cooktop edge. This may not be practical for all cooking cases, and one then has to be a tad choosy about what burner or hob he uses when generating hot (high upward velocity) greasy effluent.

And the answer to homepro1's question is important because a suitable blower for this large hood will have significant size, and one wants it well above the baffles to ensure good flow distribution.

kas

Blower will be in-hood, not remote....Prizer said that they could do the 15" height with the thicker baffles they use in their typical 18" height hood...

So if 30" is the lowest one should go, then what would be the ideal height to set the hood above the cooktops? I am only 5'2" so functionally 30" would be ok for me and I am the only one cooking in my family. Of course guests may occasionally want to use the cooking surfaces but I don't foresee that to be a regular occurrence.

Kas is the go-to source for the physics. Having read numerous manuals, I can tell you that 30" is a pretty standard recommendation. I think that's more about standard building practices than customized for any particular stove, but it's kind of normal. Only particularly tall people have issues with that. You look down into your food, rather than out, so bonkage really isn't a big issue.

If you have a good reason to put the hood out of easy reach for the switches, you can put in remote switches in the wall or counter. It used to be a regularly loved adaptation around here. People also use them to put a variable controller on a unit that only has one or two speeds, but there's more to it than the switch (the controller has to work right with the guts, and that's as technical as I get), so can't be done with every unit. Or something like that.

Heh. Lowest you can cook with is ideal for capture. But as you note, you may not be the only cook. Also, it is necessary for the height to work both bending and looking into pots of various heights. And this depends on front-to-back depth as well as height. This is why I always suggest side view stick figure drawings to catch any potential inconveniences. And for island hoods, sight-lines across rooms can be a factor. So ideal depends on many factors, some of which are likely to be conflicting, thereby requiring the buyer/user to trade-off the pluses and minuses of a given configuration.

Thanks Kas and Plllog. I think we will stick with the 30" height, but I will make a side view stick drawing to make sure! The hood will be on the back wall of the kitchen so hopefully it won't be in the way.

By the way, do you have any preference between flush-mount and surface-mounted induction cooktops? Reading through the previous posts it seems that people liked both, but surface mounting seems less risky, and is a much easier install? Why is it that surface mounting makes it easier to replace the cooktop in the future?

The only reason I would want to flush mount is so I can hang big pots and pans off the edge of the cooktop, which I wouldn't be able to with a stainless steel lip....but on the other hand perhaps it's not such a good idea to have part of a hot pot/pan touching the marble? I could care less about the look of flush mount vs surface mount....

Surface mounting makes replacement easier because it doesn't need a highly customized hole. Nominal 30" units run from 28"-32". With flush, you'd need an exact fit. With surface, you only need there to be enough support for the edges. A slightly smaller or larger unit might fit, or the counter can be adapted for it to fit (e.g., a little more plywood underneath, or a slightly enlarged hole).

I have a stainless frame (which looked better near the stainless gas with black grate than all black would have). I have no need to hang pots over the edge, but there's nothing about the frame that would prevent it. I'm guessing you're talking about the kind that's just a vertical border, and that might be a problem, however... If your pots are that oversized, you may not like the cooking. There will be a distinct hot spot in the middle where the inductors are. An inch in diameter (half an inch all around) over is expected. An inch in radius (an inch all around) over is perfectly doable. By the time you get two inches past the ring, you're losing a lot of ease of cooking. That said, you can use a silicone mat, both on the stove and on the counter, to equalize the height.

Marble is rock. It can take a hot pot. What you don't want do, especially where it's weakest, is thermal shock, which could promote cracking, so a trivet is a good thing to have. If it warms along with your pot, gradually, it'll be fine. As to scratches, etching, spots, etc., that's another story entirely, but all of the above can be helped by the silicone mat.

With all this talk about induction cooktops, I just wanted to mention the Thermador 36" Masterpiece Freedom Induction Cooktop. This cooktop stands out from the rest, for me, because you can place up to 4 pans on it anywhere and the cooktop senses and adjusts for them. And if you need to reorganize or put something on the "back burner" no problem, it automatically senses where your pans move and keeps their settings. Very cool, and no more worrying about placing pans right on the burners, etc. http://www.thermador.com/cooking/cooktops/cit36xkbb-36-inch-masterpiece-series-freedom-induction-cooktop 

Also the GE Monogram 36" induction cooktop has a "sous vide" accessory that you can clip on your pot and it communicates temperature information to the cooktop. Not sure how great it is compared to a traditional water-circulating device, but one less gadget to worry about storing 360 days a year for the casual home chef. http://www.cnet.com/products/ge-monogram-36-inch-induction-cooktop-with-sous-vide-accessory/

Plllog, thanks for the tips about surface mounting and the silicone mats! What a great idea to equalize the height -- would have never thought of that.

Jeffreydn, definitely considered the Freedom, but not large enough by itself for my style of cooking.

Finally decided definitively that I will go with the 30" Miele surface mount plus the 24" Bluestar Rangetop. Thanks to ALL for your helpful comments!!!

On the 42" Miele. They offer the same configuration is a 36", KM6388. Just not yet in the US. The Bosch Benchmark is the same configuration and available.

http://www.miele.co.uk/domestic/hobs-and-combisets-2473.htm?mat=10083140&name=KM_6388

Those Thermador/Gagg freedom induction units seem like great ideas until you realize that the controls panel cuts into the active part of the cooktop a bit. Once you put a big pan/pot on one side it is hard to fit anything but a small pan/pot on the same side.

For hot pans on sealed stone, be aware that some sealers can scorch if exposed to a pan with a high thermal load (think cast iron Dutch ovens and the like for example).

Skik2000, my thoughts exactly! I went a little overboard and tested the Gagg full surface live three times...and it just didn't live up to the hype. Not enough space, uneven heating etc.

Sidpost, good to know about the sealed marble!

Dan -- Was initially leaning toward the 42" Miele but scared off by the fact that nobody else makes a 42". And Bosch's bridge elements are too narrow for my liking.

How much do you rely on AC for your home? 1200 CFM hood displaces a whole lot of "conditioned" air, which would be replaced with outside air. Now for quantity of cooking places, it would seem two independent induction cooktops would take care of the issue. Of course you'd have to have two high powered electrical circuits for the two units. But nothing different than providing a whole lot of gas to your Blue Star cooktop.

Now for the 42" Miele - don't do it. I have a 34" Jenn-Air gas downdraft vent cooktop which is causing me grief looking for a new induction cooktop. I'll need to find a great granite company to be able to change my counter top to do anything in a normal size. I haven't found one that can adapt my counter without breaking things, which would mean fixing a island counter with bar etc., etc.,.... Don't do non-standard cooktops.

One advantage of two cooktops and two hoods, alluded to above, it that so long as very hot cooking is not done on both cooktops at the same time, the total air flow needed will be less than needed for one all encompassing hood. (Air flow follows from hot-effluent required air velocity which of necessity has to be adequate across the entire hood aperture because the aperture space cannot be variably closed off.) This will have a modest advantage in MUA cost and fit, and possibly hood noise. Depending on kitchen layout, dual hoods with separated cooktops may be more or less convenient than a single hood. Dual hood systems will, due to overlap requirements, take up more length along the counter.

Another option providing a more integrated and quasi professional look would be a custom hood with an internal partition and dual blowers with separate controls.

eliasgrace, what did you end up settling on? We have a 42inch Viking electric cooktop that needs to be replaced and want to go with induction. I, like you, found that Miele is the only 42 inch option. I really need to make the existing opening work as it is brick under a beautiful copper hood.