Induction hob and old brass pan

[pmailkeey]

What's with the lack of edit feature on that wiki ?

News: reader - hmmm, hang on a mo...

[Andy Burns]

I think accounts are granted more or less on request

[The Natural Philosopher]

an induction furnace :) Putting anything in the brass pan won't get detected by the hob as there's too much brass in the way which is too conductive for the hob.

According to wiki you buy a steel disk and stick it on top and the pan on that.

BUT I think the wiki article is written by someone with very little electrical knowledge.

Seems to confuse skin effect with resistance, which is anyway irrelevant at this level of frequency, and mistake the reason for using fibre would wire instead of single for enamelled. Basically flexibility and heat.

Also this is an induction hob, and eddy currents are not really the point. Its pure resistive heating. Steel or ferromagnetic material is only useful in that it concentrates the flux more, but brass will still heat in an AC field from pure - guess what - INDUCTION.

[polygonum]

I am not convinced that brass will work - even if only because the control mechanism won't let it - maybe simply by mis-detecting what is there.

[pmailkeey]

Induction works with any metals. I believe the domestic induction hob has s ensory electronics to avoid overload - and this is why they quit working wi th brass, copper, Alu etc. The idea of inducing currents in ferromagnetics seems logical in that the induced electrical current in the base of the pan generates an alternating magnetic field within the pan and these currents significantly help the heating rather than the pure electric load.

Think of the hob as a transformer - many turns in the primary coil in the h ob and one turn in the pan - therefore an induced very high current and v. low voltage in the pan. The high current generating heat and in the ferroma gnetics generating heat from magnetic eddy currents.

As I believe 'metal' derives from a material's ability to conduct electrici ty, any metal will work with an induction source to produce heat - but not all induction sources will work with any metal - due to protective overload circuitry.

[The Natural Philosopher]

then slap an iron slab on top

[Fred]

Me neither ;)

I was thinking of having an induction hob when we complete the kitchen refurb. We would need some new saucepans to be compatible with this and besides, the ones we have are on their last legs anyway.

I didn't know anything about saucepans, so I read here:

I thought iron would be best but the link suggests that because there is so much mass to iron pans, they take longer to heat up and continue to hold heat even after the hob is turned off. It also advises about the weight of the pans when full. So all of these have put me off iron pans.

I was surprised that the web site claims steel does not conduct heat very well, I thought all metals did. Surely steel pans must conduct better than glass ones?

The web site mentions copper, but I haven't seen any 100% copper pans (and of course they would not work with induction). Pans sold as "copper" seem to have an outside copper layer and then inside layers of steel or aluminium, which is very misleading imho.

So I guess I will end up with some aluminium ones that I presume have a steel base. I would have thought aluminium leaching would be more of a health concern that copper leaching but I think the anodising prevents that.

[polygonum]

I think our are all stainless in various makes and forms. Oh - maybe a frying pan or two are aluminum with a suitable steel bit in the base. Have no problem with speed of heating up.

Have in the past used iron - yes heavy, yes retains heat. I like frying on iron, got an enamelled iron casserole, but wouldn't choose it for much else.

[Clive George]

The thermal inertia and general mass makes them really good for some things (eg simmering), so it's worth considering getting one or two.

Stainless steel doesn't conduct heat as well as eg copper or Al. Hence stainless drinks flasks.

Decent stainless pans have an Al or Cu base which makes them work rather better. I'd go for these - they work well and can take abuse.

[polygonum]

I thought that stainless was used for flasks because it offered a combination of strength despite thinness plus safety and gas-tightness which would not be possible with copper or aluminium.

[Clive George]

If you made a drinks flask out of copper or Al you'd end up with cold tea very quickly :-)

Look at the numbers for the various materials. Stainless doesn't conduct that well for a metal.

The strength is another good reason to use it, but you wouldn't use a material with the strength of stainless and the conductivity of copper.

[Dave Liquorice]

Cast iron presumably, like Le Cruset? They are heavy and do hold heat not a problem on gas or induction but on hot plate electric would be a nightmare.

Copper used to be used, look in the kitchens of victorian country houses. The inside was tinned, (with tin, not solder,,,) though not bare copper. The scullary maid would have to keep the outsides polished.

Not seen ali pans that are anodised normally bare ali. I don't like coatings on pans, it wears off.

The ones we have here that are induction hob suitable are stainless steel with a fairly thick base that presumably has a lump of iron in it. Respond very quickly to changes in heat setting, not quite as quick as gas but not far off it. Meyer Bella Classico these are quite old, >10 years, and the current range of the same name on the web doesn't mention induction. Maybe they have changed the construction of the pan base?

[polygonum]

It is not a matter of thermal conductivity - there is a vacuum - which is why they are vacuum flasks. The only bit that really matters thermal-conductivity-wise is the small bit around the neck.

[Alexander Lamaison]

What makes 'hot plate electric' different for cast iron? And do you mean a solid metal hob or a flat ceramic one? Asking cos I'm thinking of buying the latter.

Alex

[polygonum]

There have been quite a few shattered ceramic hobs caused by careless use of cast iron pans.

[Andy Champ]

Just done exactly that. Had to buy new pans - got a set of stainless ones which were a special deal in Debenhams.

Inductions hobs are the dogs wotsits. Far FAR faster than gas, which is the fastest thing I'd ever used before.

I've just gone and checked - it will go from cold to boiling half a pint of water in under a minute.

On the other hand, they are useless for woks...

Andy

[polygonum]

There are special induction rings for special woks...

(I didn't even bother to think about the cost...)

[The Natural Philosopher]

+1

[The Natural Philosopher]

one here. No, not me. A previous GF/s thick brother

[Alexander Lamaison]

Is it just a case of impact, or is it a thermal issue too? SWMBO is careful the the point of obsession so, if it's the former, she should be fine.

Alex