MythBusters - Pizzamaking Edition

[Jackitup]

Just for S & G I just went out in the garage and slowly poured about 1/2 cup of water onto the cordierite stone on my BS, water never reached the sides, literally sucked it up like a sponge leaving the surface barely moist. Blowing into this surface anyway I think would be like fabric albiet very hard fabric. I was even suprised at how much liquid it aborbed, VERY porous. Now this is not screaming hot but would demonstrate the difference from a sealed stone vs a very porous one.

jon

[mitchjg]

Just for S & G I just went out in the garage and slowly poured about 1/2 cup of water onto the cordierite stone on my BS, water never reached the sides, literally sucked it up like a sponge leaving the surface barely moist. Blowing into this surface anyway I think would be like fabric albiet very hard fabric. I was even suprised at how much liquid it aborbed, VERY porous. Now this is not screaming hot but would demonstrate the difference from a sealed stone vs a very porous one.

jon

Now try it screaming hot..............but I hope you do not mind a cracked stone........it is a sacrifice for the sake of science and knowledge. 

[Jackitup]

Now try it screaming hot..............but I hope you do not mind a cracked stone........it is a sacrifice for the sake of science and knowledge.

I'll wait till I need a new one

[TXCraig1]

Now try it screaming hot..............but I hope you do not mind a cracked stone........it is a sacrifice for the sake of science and knowledge.

Exactly. Pouring water on a cold stone is meaningless in terms of this discussion. Not just because it would turn to steam on a hot stone, but more importantly, no liquid water comes out of a pizza dough.

[Jackitup]

Exactly. Pouring water on a cold stone is meaningless in terms of this discussion. Not just because it would turn to steam on a hot stone, but more importantly, no liquid water comes out of a pizza dough.

I agree with you. I only did it to see how porous the stone is and it's actually much more so than I thought. Also agree, regardless of the stone composition, an extremely hot stone will not absorb water, but I think there is something to be said for the stones porous nature to diffuse steam/vapor/gas vs a sealed stone. It may not be significant enough to call a night and day difference but it's enough to affect a difference in the finished bottom browning and texture of certain baked goods like breads and pizzas and such. Is it better or worse......I think is a personal preference on ones tastes and what you're looking for aesthetically

jon

[jkb]

At the risk of having my physics degree revoked, I don't give a damn about this.  All that matters is that the pizza tastes good.

[Jackitup]

  tru dat. Still fun, and makes us all think about how and what we do a little differently!

jon

[TXCraig1]

but it's enough to affect a difference in the finished bottom browning and texture of certain baked goods like breads and pizzas and such.

On what are you basing that conclusion? I haven't seen a test that demonstrates that. If anything John's test of parchment suggests just the opposite.

[Tampa]

On what are you basing that conclusion? I haven't seen a test that demonstrates that. If anything John's test of parchment suggests just the opposite.

If I understand the result from John's parchment test, it is that the bottom of the pie appears relatively crispy.  Parchment, like aluminum foil, is presumed to be non-porous so the steam didn't have a chance to get absorbed by the stone (if such absorption does indeed occur).

From Wikipedia: Modern parchment paper is made by running sheets of paper pulp through a bath of sulfuric acid (a method similar to how tracing paper is made) or sometimes zinc chloride. This process partially dissolves or gelatinizes the paper.

I'm not so sure that parchment results support the foil hypothesis since many things are different between the two mediums (eg: metal/non-metal, emissivities, stickyness to the dough, conductivity, etc.).  Parchment browns at baking temperatures and foil doesn't.  Are the porosities of aluminum foil and gelatinized paper the same at say 600F with the steam as the fluid?  I dunno

I'm still wondering about this myth.  It seems a complicated boundry layer problem.  New ideas welcome.

Dave

[TXCraig1]

Someone needs to sacrifice their Emile Henry stone...

[Crispy Please]

Someone needs to sacrifice their Emile Henry stone...

Thanks for referring to this Craig. Different materials will produce different results (leoparding, browning, crisping, etc.) for many reasons which have been more than amply covered in this thread. But seriously, stone, ceramic, glazed, vitrified, and or steel plate simply cannot absorb H2O when heated to 600 degrees because, if for no other reason, the water evaporates on contact.

May I have another slice now?

-Crispy

[Bobino414]

Until the Emile Henry stone shows up, maybe we can move on to the next myth?

[Jackitup]

On what are you basing that conclusion? I haven't seen a test that demonstrates that. If anything John's test of parchment suggests just the opposite.

No tests, just my experiences over time and baking on any number of stones and ovens. Mine is not near as extensive as many here but just looking at the plethora of stones, surfaces, ovens, temps, thickness factors.....all for each persons desired results per their needs and desired results. Can a hot stone aborb moisture, probably not. But I think it's obvious that many factors affect the end result in bottoms of crusts and near the top would be porosity and it's nature to diffuse or lack of porosity. I can tell the difference even from my Fibrament vs the cordierite. They are close but their is a difference. And lastly as I mentioned before, all about preference and where/how each stone is used. Is there a test to prove one over the other......I think it's the old Miller commercial......"Tastes Great.....Less Filling"

jon

[Tannerwooden]

Thanks Craig for bringing this up. I've always accepted the myth without thinking. I will eagerly await the next episode of Pizza Myth busters. In fact, I would love to see it get its own tab on the forum. I think there's a TON of fodder for future episodes (Blind taste test: Are San Marzanos really the best?, How helpful is Autolyzing?)

I'm wondering though, what if you MADE the stone porous enough for steam to escape? What if you drilled holes in it? Would the steam travel down? We know from  bubbles that it's down there. You would certainly lose heat retaining mass, but would there be a compensating benefit? Would there be a sweet spot? 1/2" steel would be a  great one to try this out on, as there is already SO much mass to begin with.

On testing the sourdough myth: Does anyone know if you can see the difference between different strains of yeast with a reasonably priced microscope? This would make some aspects of testing the myth easier.

I read an article in Popular Science a few years ago. Someone in Germany had the idea of genetically modifying plaque forming bacteria so it generates alcohol (miniscule amounts) instead of plaque. They did it and decided to test it on themselves (beginning of a zombie movie). It didn't work. The modified strain was immediately killed by stronger bacteria in the guy's mouth.

He proceeded to get hundreds of samples of saliva. He used the samples to have petri dish cage matches (Two Bugs Enter. One Bug Leaves!").

Long story short, the author of the article claimed the guy hasn't brushed his teeth or gotten a cavity in months. Could you do the same sort of experiment with starters?

[David Esq.]

Everybody says water becomes steam on contact with a 600 degree surface. But that is absolutely not what happens when the dough hits the stone.

First, as Craig points out, water does not come out of the dough in a liquid state.

Therefore, a cold dough hits a hot surface. And the temperatures begin to equalize.  While that process begins, the stone cools and the dough warms.

Eventually water leaves the dough at the top, for certain, in vapor form.

What is the temperature of the stone surface throughout the bake? 

At what temperature does water drawn out from dough "instantly" turn to steam on contact? What happens to that steam when it is under 1 PDO (pizza dough pressure)?  Does it condense into water and does water under 1PDO turn to stream at 212 or a higher temp?

[CDNpielover]

The problem with that theory is that the amount of water (in the form of steam) needed to fill the pores is a tiny fraction of a gram. Once the pores are filled, it will act the same as a solid surface. Try to blow into the stone, it's not like blowing into a fabric. It doesn't breathe like you are thinking. Also, if the stone is hotter than the pizza bottom, the pressure in the pores in the stone will be higher than the pressure of the steam coming out of the pizza above the stone and thus it will not enter the stone.

the pores don't "fill", they provide pathways across which water vapor can move.  Just like soil, concrete, wood, etc., the stone has a conductivity that could be measured.  your data show this.  A porous stone is going to permit way more water loss than a slab of steel.

[CDNpielover]

Just for S & G I just went out in the garage and slowly poured about 1/2 cup of water onto the cordierite stone on my BS, water never reached the sides, literally sucked it up like a sponge leaving the surface barely moist. Blowing into this surface anyway I think would be like fabric albiet very hard fabric. I was even suprised at how much liquid it aborbed, VERY porous. Now this is not screaming hot but would demonstrate the difference from a sealed stone vs a very porous one.

jon

exactly 

[Tscarborough]

At 600 degrees the absorption rate of corderite or (almost anything) is effectively and absolutely 0.0.

[TXCraig1]

the pores don't "fill", they provide pathways across which water vapor can move.  Just like soil, concrete, wood, etc., the stone has a conductivity that could be measured.  your data show this.  A porous stone is going to permit way more water loss than a slab of steel.

It doesn't work like that. Whatever minuscule amount of moisture that gets into the pores will expand as it heats preventing additional moisture from entering.

The water is coming out of the pizza one way or the other. A slab of steel isn't going to hold the water in any more than a stone is going to suck it out.

[CDNpielover]

At 600 degrees the absorption rate of corderite or (almost anything) is effectively and absolutely 0.0.

The water doesn't absorb into the corderite, it evaporates into the hot, dry air in the pores.  It's the same exact process that happens on the top of the pizza.  If you think the pores are too small to transport significant amounts of water, do some reading on plant stomata.