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I recently made an Aluminum baking "Steel" for baking pizza. The entire point of Aluminum is that it is orders of magnitude more thermally conductive than steel and (relative to its weight) has a higher thermal capacity; While not sharing the same sort of cost as copper.

But one thing I have never heard mentioned is the thermal properties of adding an anodized/oxidized layer or a seasoned layer. Is their any research or scientific theory on what thermal peripheries a layer of seasoning adds to an aluminum cooking surface vs just lettings the surface oxidize/get professionally anodized?

FuzzyChef
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Jonathon
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  • Why the pizza-stone tag? And why do you care about thermal conductivity in a baking steel at all? – rumtscho May 17 '21 at 15:24
  • Isn't the whole idea of a pizza steel/stone that it retains heat? If Aluminium were a better material, then surely that's what people would use. – Tetsujin May 17 '21 at 15:25
  • @Tetsujin That is what people use, I did not invent the idea. – Jonathon May 17 '21 at 15:38
  • @romtscho Because that is the tag used to denote products used to cook pizzas on. Seasoned Advice does not have a different tag for every material used. Wither you use a ceramic, steel, or aluminum, a pizza stone is used to concentrate the heat of your oven. Over the preheating stage it absorbs a tremendous amount of heat energy, and because of its high conductivity it can take 500 degrees and make it feel like a professional 700 degree oven. It is like how metal left out in the sun will burn your hand, while wood left out in the sun will not and stone is somewhere inbetween. – Jonathon May 17 '21 at 15:43
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    So you mean that you intend to use your new implement to bake pizza on it? Because this is not recognizable from the title or text of your question. – rumtscho May 17 '21 at 15:50
  • While you're right about aluminum's better conductivity, the problem with it is that it has much lower density than steel, leading to lower mass unless you make it much thicker. AFAICT, that's why folks don't do Al baking steels. – FuzzyChef May 17 '21 at 15:51
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    BTW, please blog your Al-steel experience. Nobody's really experimented with this, so your results will be interesting. – FuzzyChef May 17 '21 at 15:52
  • @Tetsujin Not that aluminum is common, every step up in price(and performance) is +90% less common from what I have seen (stone->steel->aluminum). – Jonathon May 17 '21 at 15:53
  • @rumtscho Ah, I see your point. The baking Steels are only used for pizza (more or less) but that might not be obvious from reading this. – Jonathon May 17 '21 at 15:55
  • @FuzzyChef I will try, but it will be hard to give any results that than: "it tasted good before, and I think I might light it slightly better now?" It is not like I am likely use any other method beside the aluminum to test side by side. Here is all the info I have read about it (https://www.reddit.com/r/Cooking/comments/ejjm20/dimensions_for_bakingpizza_steel/fd60do1/?utm_source=reddit&utm_medium=web2x&context=3) – Jonathon May 17 '21 at 16:01
  • @FuzzyChef Yes, you typically want 1" of solid aluminum, while the typical steel would be 1/2". The volume goes up, but you can store more heat in 1lb of aluminum than 1lb of steel. – Jonathon May 17 '21 at 16:03
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    Well, if you're doing pizza, photos of crust rise and bottom browning are common. Example from my blog: http://fuzzychef.org/ooni-koda-hacking-part-1/ Sadly, you'll have to share that somewhere else since SA is a Q&A site. – FuzzyChef May 17 '21 at 16:05

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A surface insulating layer (whether deliberate anodising, natural oxidation, or seasoning) will only really affect the heat flow through that layer from the bulk metal into the food on top. It won't affect the heat-spreading effect used for even cooking, and it won't affect the heat capacity.

So now we're considering the difference between various surface layers. These will probably have a similar thermal conductivity to a ceramic pizza stone (to order-of-magnitude precision), but being thin layers between the food and the aluminium sheet heat reservoir will have a small effect compared to the temperature drop between the core of a pizza stone and the food on its surface. This means whatever has happened to the surface you'll couple the heat from the sheet to the food better than with a pizza stone, which would appear to be your goal.

The thermal conductivity of most foods that you'd cook on a stone/steel will be far lower - most consist of dough with gas bubbles in, basically insulating foam. That's what will limit the time for the middle to cook through. Perhaps a smoother layer will give better contact, but clean seasoning and anodising are both quite smooth.

More of an issue than thermal effects will be sticking. This is an application where you really don't want the food to stick, as it will carry on cooking while you free it up. It will also be a pain to deal with as I find with my home made aluminium pizza peel on thin bases. Hopefully the thorough, fast cooking will avoid sticking in the first place, but spills of sauce etc. will still need to be cleaned up, so a bigger question than heat flow would be ease of cleaning.

Chris H
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