1821 replies to this topic

[Chris Amirault]

How much is that gonna weigh?

[jmolinari]

a 0.75" 16x16 316L plate is about 55lbs.

Check out this calculator: http://www.onlinemet.../calculator.cfm

[Dave the Cook]

316 is commonly used for food applications. As far as heat is concerned, what are you worried about? It's not going to melt unless the heating element in your oven can reach 1375°C (about 2500°F).

[jmolinari]

What's interesting to me is that a 18x18x0.75 316 steel plate is about $800....sooooooo.....

[roygon]

Is Aluminum going to be ok and is there a specific type/grade I should be looking for? A buddy of mine has a CNC shop and a 3/4 inch aluminum sheet that fits my oven will run around $100 but I'm going to wait for some results, and the book to see the specifics, before I make a decision.

rg

[nickrey]

My understanding is that the metal is a heat sink in the oven. You don't actually cook on it. If it doesn't come into contact with the food and doesn't melt or release noxious chemicals when heated there shouldn't be a problem. Maybe I'm misguided but this makes more sense to me.

Edited by nickrey, 22 February 2011 - 04:24 PM.

[b-ry]

I have not seen what the book says, but the WSJ article referring to the book says:

Get a ¼-inch-thick sheet of steel from a metal fabricator (Google a local one), have it cut to the size of your oven shelf and insert it in the rack closest to the broiler. Preheat the oven at its highest temperature for ½ hour, then turn on the broiler and slide your pizza onto the metal plate. It should emerge perfectly cooked in 1.5 to 2 minutes.

I was quoted $295 for 1/4 inch measuring 17 x 23.75.

[b-ry]

I am not well versed on safe conditions when it comes to heating different kinds of steel. I learned that non-stainless steel has contaminants. I was not entirely sure, but when the steel fabricator and supplier couldn't confirm that there weren't any safety issues, I was a bit concerned. Doesn't All-Clad use T316 and they warn against temperatures above 500 and using the broiler?

[blackp]

Why would anyone be concerned with cooking pizza on aluminium?

Most pizza restaurants (except for those with wood fired ovens) make their pizzas on aluminium pans and they use ovens which can reach 600C.

A very large percentage of commercial saucepans are aluminium also.

The only issue with aluminium is that it is not good to hold anything acidic after the cooking is over.

So given that aluminium is cheaper and lighter than steel or stainless steel - would it perform as well?

Regards,

Peter.

[JBailey]

One of Nathan's Seattle neighbors is Wood Stone who make the ceramic cooking ovens seen in so many restaurant kitchens. They have developed a method to cast the floors and walls of their wood fired and gas fired ovens with their proprietary high-temperature ceramics.

As I shared elsewhere, in my oven I have one of their baking slates which is the ceramic material poured into a baking sheet pan. It works wonderfully as both a heat sink and as a pizza stone. They are not cheap, but I believe may work for what you desire.

[jmolinari]

The point of the steel plate is the heat transfer properties. It is able to transfer much more heat more quickly than a stone can, which is why, theoretically, baking a 2 minute pie is possible even if the steel is only at say 550, instead of 800 for a stone. The same amount of enegery is transferring into the pie in 2 minutes from either a 550 deg. plate, or an 800 deg. stone...at least that's the theory.

It makes sense. though i'm quite sure a 1/4" plate would not have sufficient thermal energy stored to work...whoever said 3/4" is probably more accurate. If th

[dcarch]

"---The point of the steel plate is the heat transfer properties. It is able to transfer much more heat more quickly than a stone can, ---"

I see that potentially a problem, not an advantage. When heat is transferred faster than a pie's ability to conduct heat, the outside gets burned, and the inside gets un-cooked.

Besides, the permeability of stone allows steam to escape and allows crispier crust to develop.

dcarch

[jmolinari]

Agree on the stream aspect, thought the same thing. I'm just explaining the theoretical physics behind the system. I assume if they wrote about it in the book they actually tried it, and the bottom wasn't overly burned before the center done.
My concern is having the top done before the bottom burns. Ghats the hardest balancing act.

I don't know about other ovens but if preheat mine to 500 (max) the broiler isn't coming on bc theoven is already maxed out. The boiler doesn't just come on no matter what, is overridden by the current oven temp.

[nickrey]

Having reread the appropriate section in the book, you do place the pizza directly on the metal plate to cook.

It's an extension of the technique described in the quest for perfect pizza reported in Heston Blumenthal's "In search of perfection." This is not a surprise because Chris Young, who is one of the co-authors of this book, assisted Heston Blumenthal in development of the original technique (something that is acknowledged in the text of Modernist Cuisine).

In the Modernist Cuisine book, they recommend using a steel or aluminium plate 2cm (3/4 inch) thick for the process.

Another alternative they mention is to use an inverted cast iron pan as your cooking base. Before you go out and buy expensive equipment, it may be worthwhile checking the book for substitutes.

[Paul Kierstead]

I see that potentially a problem, not an advantage. When heat is transferred faster than a pie's ability to conduct heat, the outside gets burned, and the inside gets un-cooked.

Perhaps what you are thinking of as "pizza" is not what they are thinking of (or at least not what this technique applies too). Consider Chicago-style vrs Napoli-style pizza, and the difference in cooking them

Edited by Paul Kierstead, 23 February 2011 - 06:34 AM.

[dcarch]

Actually, I can see steel plate for pizza, but not for pies.

You are basically dry-frying, frying without oil.

The steel plate is so hot, the steam generated actually lifts the pizza up (similar to hovercraft) to avoid burning too quickly and sticking.

dcarch

[cbread]

I am not well versed on safe conditions when it comes to heating different kinds of steel. I learned that non-stainless steel has contaminants. I was not entirely sure, but when the steel fabricator and supplier couldn't confirm that there weren't any safety issues, I was a bit concerned. Doesn't All-Clad use T316 and they warn against temperatures above 500 and using the broiler?

If you are cooking at home, mild steel - also refered to as non-stainless steel - is fine. As is thick aluminum plate. Mild steel will be by far the least expensive.

I'm guessing your fabricator is unwilling to vouch for materials that are not approved for restaurant usage. Keep in mind that a cast iron pan is basically elemental iron and carbon. Mild steel is elemental iron and carbon. Slightly different ratios, but it is for the purposes of food safety a distinction without a difference.

The contaminants idea is pretty much bogus, but in out litigious society businesses have to take liabilities real and imagined into account when they talk to the public. I'm sure that one could theoretically add contaminants to any pizza stone, but in the real world the same real cleaning you would give any new kitchen item will take care of the usual dirt and gunk that transportation, packing, handling etc entail.

Edited by cbread, 23 February 2011 - 01:43 PM.

[lesliec]

When I bought my first cast iron pan the guy in the shop gave me good instructions about seasoning, etc. The first step he recommended was to put a good layer of table salt in the pan and heat it on the stove; the theory was this would 'suck out' any contaminants in the iron. I have no idea if there's any science behind this, but I figured it wasn't likely to harm anything. No reason you couldn't do the same for a simple steel plate.

[emannths]

So I've started thinking about St. Patrick's Day so that I don't miss my brisket curing window. I'm curious how MC deals with corned beef (3.169, it looks like) and cured meats in general. The execution of curing meats seems to be pretty straightforward, and in the duck confit recipe, there didn't seem to be any curveballs until the cooking. I guess I don't know what to expect--maybe a treatment of wet vs dry cures, curing time, and cure salinity? Or commentary on the appropriate timing of when to introduce spices (a la the marinade debate)? Or is their advice simply a more parametic-version of the Ruhlman/Polcyn treatment? More selfishly, I was planning on using the Ruhlman recipe, but if MC says it can be done better, and one of you can give me a general idea of their recommendations, I'll give it a go.

[nathanm]

OK, so here are some comments about the pizza plate.

The key idea is to get a very hot surface to cook the pizza on, which has sufficient heat capacity. The thin metal used in pans does not have sufficient heat capacity for this purpose.

A ceramic pizza stone will work, but it transfers heat more slowly. The great thing about a thick metal plate is that the thermal conductivity of metal is very fast, so when you put the pizza on the metal plate it transfers its heat to the pizza fairly quickly.

The thicker the metal, the more heat capacity, but also the longer it will take for it to heat up. You can use anything from 1/4" thick up to 1" thick. Concievably you could even use something thicker. The page in MC says 3/4" but you could use something thinner. In fact, I might change the text to say that for the next edition.

Stainless steel, aluminum and mild steel are widely used in cooking. Most cookware is either 304 or 316 stainless. This is expensive if you get a really thick piece, because it weighs a LOT as a post above points out.

The only advantage of stainless is that it won't rust, but that is not that big an advantage frankly.

Woks, and many saute pans are mild steel, and they are used in many restaurants. You will need to rub cooking oil on the pan after washing it to prevent rust - just as you would for a wok or cast iron pan. There is a section in MC showing how to do this for a wok - doing it for a steel plate is essentially the same.

Mild steel is MUCH cheaper than stainless. A 1/2" thick plate ought to be easy to find and that should cost $30 to $50. You could go thicker if you want, but it gets very heavy so be sure you want to lug it around.

Aluminum is the most convienent choice because it weighs less. In that case 3/4" plate should cost $60 to $70 depending on size. The actual alloy of aluminum does not matter much, but 6061 is a pretty standard aircraft aluminum.

Scrap metal places may have stuff cheaper. There are places online that will cut metal to order and ship it you if there is nobody local, but usually there is a local supplier.

By the way, we also recommend a 3/4" thick to 1" thick aluminum plate to go on top of a gas burner if you want very even heat. It is much cheaper than an All Clad or similar fancy pan, and does a MUCH better job of evening out the heat. Evenness is not needed as much as people think - there is a section on this in the book.

Whoever cuts it for you should deburr the edges so you don't cut yourself. That just takes a few minutes with a file or grinder.

[nathanm]

So I've started thinking about St. Patrick's Day so that I don't miss my brisket curing window. I'm curious how MC deals with corned beef (3.169, it looks like) and cured meats in general. The execution of curing meats seems to be pretty straightforward, and in the duck confit recipe, there didn't seem to be any curveballs until the cooking. I guess I don't know what to expect--maybe a treatment of wet vs dry cures, curing time, and cure salinity? Or commentary on the appropriate timing of when to introduce spices (a la the marinade debate)? Or is their advice simply a more parametic-version of the Ruhlman/Polcyn treatment? More selfishly, I was planning on using the Ruhlman recipe, but if MC says it can be done better, and one of you can give me a general idea of their recommendations, I'll give it a go.

We have a very extensive section on cured meats, including a novel approach to curing we call "equilibrium curing". We make pastrami all the time, and our recipe is one of our favorites.

[nathanm]

By the way, there has been a lot of press on the book recently, much of which discusses recipes or what the food tastes like.

Wired Magazine has a big article.

The Washington Post also has an article about the book, which inculdes a couple recipes. They also have a Q & A section. There is also an article about one of the dinners we had for food writers and chefs.

Newsweek also has an article.

[blackp]

OK Nathan,

I read the Wired article with interest and having tried Heston's chips with some success I now find that having a chamber vacuum machine is not enough to make the perfect French Fry (we call them chips here in Aus like the Brits).

Does the book explain the equipment needed for ultrasonic cavitation? I have a small device which uses ultrasound to clean my wife's jewellery, but given it only holds about 1 litre of water I'd need lots of small bags of potato batons and a long time.....

With any amount of luck I'll have my copy of the book(s) within 2 weeks - I can't wait!

Cheers,

Peter.

[b-ry]

OK, so here are some comments about the pizza plate.

The key idea is to get a very hot surface to cook the pizza on, which has sufficient heat capacity. The thin metal used in pans does not have sufficient heat capacity for this purpose.

A ceramic pizza stone will work, but it transfers heat more slowly. The great thing about a thick metal plate is that the thermal conductivity of metal is very fast, so when you put the pizza on the metal plate it transfers its heat to the pizza fairly quickly.

The thicker the metal, the more heat capacity, but also the longer it will take for it to heat up. You can use anything from 1/4" thick up to 1" thick. Concievably you could even use something thicker. The page in MC says 3/4" but you could use something thinner. In fact, I might change the text to say that for the next edition.

Stainless steel, aluminum and mild steel are widely used in cooking. Most cookware is either 304 or 316 stainless. This is expensive if you get a really thick piece, because it weighs a LOT as a post above points out.

The only advantage of stainless is that it won't rust, but that is not that big an advantage frankly.

Woks, and many saute pans are mild steel, and they are used in many restaurants. You will need to rub cooking oil on the pan after washing it to prevent rust - just as you would for a wok or cast iron pan. There is a section in MC showing how to do this for a wok - doing it for a steel plate is essentially the same.

Mild steel is MUCH cheaper than stainless. A 1/2" thick plate ought to be easy to find and that should cost $30 to $50. You could go thicker if you want, but it gets very heavy so be sure you want to lug it around.

Aluminum is the most convienent choice because it weighs less. In that case 3/4" plate should cost $60 to $70 depending on size. The actual alloy of aluminum does not matter much, but 6061 is a pretty standard aircraft aluminum.

Scrap metal places may have stuff cheaper. There are places online that will cut metal to order and ship it you if there is nobody local, but usually there is a local supplier.

By the way, we also recommend a 3/4" thick to 1" thick aluminum plate to go on top of a gas burner if you want very even heat. It is much cheaper than an All Clad or similar fancy pan, and does a MUCH better job of evening out the heat. Evenness is not needed as much as people think - there is a section on this in the book.

Whoever cuts it for you should deburr the edges so you don't cut yourself. That just takes a few minutes with a file or grinder.

Thank you! That clears everything up. Can't wait to try this technique and I can't wait for the book to arrive!

[jmolinari]

We have a very extensive section on cured meats, including a novel approach to curing we call "equilibrium curing". We make pastrami all the time, and our recipe is one of our favorites.

Is your approach different to what the FDA handbook refers to as "method 2" for nitrate absorption? Basically where the brine, meat and spices act as a single system where given enough time an equilibrium is reached between the meat and brine?

[cbread]

... And aluminum, seriously? Come on, Nathan, you have to be aware of the aluminum's conductivity. You can pre-heat it for as long as you want and the moment you open the door, the temperature will plummet. Aluminum will not store heat- and for pizza, stored heat is critical.

The suggestion that a massive plate aluminum at 550F or similar will drop precipitously in temperature the moment the oven is opened is erroneous. Aluminum has a very high heat capacity when used in similar mass to iron and steel. I'm too slow a typist to do justice to the physics of common cooking materials and heat so I won't try. All that has been well explained here and elsewhere many a time.

Good references are:
http://forums.egullet.org/index.php?/topic/25717-understanding-stovetop-cookware
http://www.cookingforengineers.com/article/120/Common-Materials-of-Cookware

Here's a non technical way to look at it. Put a really thick aluminum pan on the stove on high and you will find it takes a long time to heat to the temperature you need. It absorbs much heat energy and only gradually attains high temperature. Some folks really don't like truly massive aluminum pans because they take a long time to heat up. Think of big slabs of aluminum as particularly effective storage places for heat when compared with similar masses of steel or iron.

The same happens in reverse. Once the pan has got to a high temperature, turn off the heat and that massive aluminum pan stays hot enough to cook for a surprisingly long time. Try it by turning it off and tossing in some food. You'll be able to do quite a bit of cooking before the pan is ineffectual. The heat can leak out of the pan only so fast.

The reason it stays hot enough to cook is the same reason a massive pizza slab in the oven will. Materials can only lose heat as fast as combined actions of radiation, conduction and convection will allow. Those are the only mechanisms by which the slab or the pan can lose heat. They happen for steel and aluminum in pretty much the same way. Aluminum's very high conductivity evens out the temperature of the pan or slab better than most materials, but it does not miraculously jet heat out of the surface in ways not allowed by the laws of physics. A pound of aluminum takes more energy to heat to a given temperature than a pound of cast iron. Takes longer to heat and takes longer to cool. There's no miracle that will suddenly suck all that heat energy out.

[Chris Hennes]

Nice summary, cbread. And of course, this is all covered in detail in the book, too. Your oven stores heat in its walls (and in any big hunk of metal you put in there...): the air is almost completely incidental. So opening the oven door has far less affect on the oven temp than is commonly assumed, since air is such a horrible conductor.

[nathanm]

Does the book explain the equipment needed for ultrasonic cavitation? I have a small device which uses ultrasound to clean my wife's jewellery, but given it only holds about 1 litre of water I'd need lots of small bags of potato batons and a long time.....

The ultrasonic cleaner we use is similar to the one for your wife's jewelry, only bigger. They come in various sizes. You could test the recipe out with a 1-liter ultrasonic bath, but you won't be able to make large quantities that way.

[emannths]

If I remember, Aluminum hold more heat than steel.

It depends on if you're talking about equal masses or equal volumes. Aluminum has a higher c_p on a mass basis, but iron has a higher c_p on a volume basis. Wikipedia has a sortable table of heat capacities.

Those thinking about this problem should definitely reread the eGCI topic on cookware if you haven't read it recently. The treatment of the various thermal properties of iron/steel, aluminum, and copper is very thorough and nicely explained.

Just out of curiosity, how fast can a pizza suck heat out of an aluminum "stone?" Ignoring issues of practicality, would putting heat xfer fins on the underside help, or does the preheated "stone" already contain enough heat at ~550F to achieve the desired results? Nathan/MC-people, did you monitor the temperature of your metal "stone" during baking?

[nathanm]

3. What I believe should be considered in the total thermal dynamics thinking of the oven is the black body/radiation characteristics of all materials. For instance, Bright Aluminum can be close to 95% reflectivity. This can make a huge difference.


dcarch

The reflectivity (and thermal emissivity) is also discussed the book, although not in the pizza section.

Basically, the story is this:

1. Because the aluminum is shiny, it will take longer to heat up than it would if it was black. This is particularly true for heat from the broiler element which will mostly be infrared radiation.

2. But, once it is hot, it will not lose heat by thermal radiation. This is why many griddles and planchas are shiny chrome - they do not lose heat to thermal radiation. So while it will take longer to heat up a shiny plate than a black plate, it will also lose heat less.

3. Once the pizza is in contact with the metal plate, heat will be primarily by conduction, not radiation, so the heat transfer to the pizza will be pretty much the same regardless of whether the aluminum is shiny or not.

4. One could make the aluminum black through a process called anodizing. This is similar to the dark finish on Calphalon pans. This would be faster to heat up than a shiny plate.

5. A mild steel plate is pretty dark, and if you season it with oil as you would a wok it will be quite dark. This will absorb heat from the broiler element much faster than the aluminum will, but the conductivity is much lower, so the trade off will depend on thickness.