Cooking With A Plancha

[bmdaniel]

I've been thinking about steam griddles ever since reading about them in MC; what about replacing a stovetop with one altogether? Any downsides?

[slkinsey]

I wonder if it would be possible to have someone fabricate a "steam plancha" for stovetop use?

For those of you just tuning in, the way these work is that there is a sealed chamber below the cooking surface that is half-filled with water. The water is (super) heated and the steam is what heats the cooking surface from below. What makes this especially good is that when you put something on the plancha and thermal energy is transferred into the food, it creates a localized "cold spot" on the plancha. Underneath, in the chamber, there is increased condensation of water vapor onto the localized cold spot, which transfers greater amounts of thermal energy right to the exact spot where it is needed. The end result is that the temperature of the plancha surface is incredibly even and doesn't get lowered underneath the food items placed on the plancha.

I'm thinking it ought to be possible to create a hollow rectangle out of relatively thick aluminum (or whatever) that is welded closed with some water inside. Needless to say, you would want to massively over-engineer the thing so it couldn't possibly explode from built-up pressure.

Just curious as to what pressure you think would be generate? Is this something, like a flat top pressure cooker, let say 15 PSI. Could achieve?

Oh no, you would want to go much higher than that. Water at 15 PSI over atmospheric is only getting up to around 250F. You'd want to get a griddle up to, say, 350f to 400F. You're talking about maybe 200 PSI over atmospheric.

[dcarch]

I wonder if it would be possible to have someone fabricate a "steam plancha" for stovetop use?

For those of you just tuning in, the way these work is that there is a sealed chamber below the cooking surface that is half-filled with water. The water is (super) heated and the steam is what heats the cooking surface from below. What makes this especially good is that when you put something on the plancha and thermal energy is transferred into the food, it creates a localized "cold spot" on the plancha. Underneath, in the chamber, there is increased condensation of water vapor onto the localized cold spot, which transfers greater amounts of thermal energy right to the exact spot where it is needed. The end result is that the temperature of the plancha surface is incredibly even and doesn't get lowered underneath the food items placed on the plancha.

I'm thinking it ought to be possible to create a hollow rectangle out of relatively thick aluminum (or whatever) that is welded closed with some water inside. Needless to say, you would want to massively over-engineer the thing so it couldn't possibly explode from built-up pressure.

Just curious as to what pressure you think would be generate? Is this something, like a flat top pressure cooker, let say 15 PSI. Could achieve?

Oh no, you would want to go much higher than that. Water at 15 PSI over atmospheric is only getting up to around 250F. You'd want to get a griddle up to, say, 350f to 400F. You're talking about maybe 200 PSI over atmospheric.

It will be very difficult.

Assuming a 2' x 3' cook top, with 30 psi pressure, it comes to 25,920 lbs of pressure. You may need 2 inch thick metal top and bottom to prevent bulging.

dcarch

[KennethT]

I agree it would be difficult - but if you were handy with welding, not impossible... rather than using such a thick piece of metal, you could use say 1/2" thick stainless, and weld 2" x 1/2" ribs in a crossed pattern which would significantly increase the moment and stiffness without all the mass...

The real trick is welding stainless which typically requires a lot of experience. If a weld fails at some point, consider the jet of high pressure extremely hot steam that would emerge from the void!

[Paul Bacino]

I am no Physics dude.. but looking and the web-site of steam flat tops.. the liquid is sealed under vacuum. Would that reduce the internal stress any!! I know it has something to do with Avacado's number!!

[dcarch]

Steam can get to extreme high temperatures under pressure.

There is a much better way to conduct heat without going to very high pressure, that is using the principle of "heat pipe" design.

Heat pipe technology is used a lot in geothermal applications to extract and conduct heat. It is also used inside your laptop to remove heat generated by the CPU.

dcarch

[slkinsey]

I agree it would be difficult - but if you were handy with welding, not impossible... rather than using such a thick piece of metal, you could use say 1/2" thick stainless, and weld 2" x 1/2" ribs in a crossed pattern which would significantly increase the moment and stiffness without all the mass...

The real trick is welding stainless which typically requires a lot of experience. If a weld fails at some point, consider the jet of high pressure extremely hot steam that would emerge from the void!

The way they do it at Accutemp is by welding in a ton of internal posts connecting the bottom and top plates.

Steam can get to extreme high temperatures under pressure.

There is a much better way to conduct heat without going to very high pressure, that is using the principle of "heat pipe" design.

It's not clear to me how a heat pipe design would confer the same benefits of using steam -- namely that greater condensation under colder parts of the upper plate mean that greater amounts of thermal energy are conducted exactly to the places where it is needed, creating a much more even cooking surface with a much better temperature recovery time.

Edited September 27, 2011 by slkinsey (log)

[JBailey]

Wood Stone offers a commercial plancha which is above and beyond what most home applications need. However, this may be intersting to reference.

[andiesenji]

I don't know if anyone ever produced a steam griddle but to achieve the even distribution of heat, there was, for a brief time about thirty years ago, a commercial oil-core griddle/grill on the market.

You can still buy the oil-core skillets, I think Saladmaster still makes them and occasionally one of the

"vintage" oil-core larger cookers, a low-sided stock pot, will show up on ebay (costly).

I saw an oil-core commercial grill/griddle at a trade show soon after I began catering. It was very expensive and I already had the Garland with the big grill but was fascinated by the demo as he showed there were no hot spots or cold spots anywhere on the surface with only a single large gas ring under it.

I think they may also have had one heated by electrical coils.

The demonstration was done by pouring pancake batter from one end to the other then turning it with two large spatulas to show the color was perfectly even along the entire strip.

He also showed other items being cooked on it but I did not stay for the rest of it.