Author Topic: MythBusters - Pizzamaking Edition (Read 16301 times)

Bobino414 · « **Reply #40 on:** May 18, 2015, 10:03:05 PM »

Well John, I'm a believer.

TXCraig1 · « **Reply #41 on:** May 18, 2015, 10:37:37 PM »

I have to agree with comments in Tampa's thread cited above that this test is fundamentally flawed due to the stark difference in emissivity between stone and shiny foil.

Jackitup · « **Reply #42 on:** May 18, 2015, 10:51:19 PM »

Quote from: TXCraig1 on May 18, 2015, 10:37:37 PM

I have to agree with comments in Tampa's thread cited above that this test is fundamentally flawed due to the stark difference in emissivity between stone and shiny foil.

Maybe coating 1/2 the stone with a high heat glazing coating like for pottery use? If one did this and only did it on one side of the stone the other side could still be used conventionally. The only thing is, you would lose the ability to flip the stone once in awhile. Just another idea......

jon

CDNpielover · « **Reply #43 on:** May 19, 2015, 12:07:51 PM »

IMO these results support the hypothesis that stones absorb moisture. The stone absorbed 0.1 g while in the oven, that evaporated in 30 s. You've been thinking of this as a problem of total stock, when instead you should be thinking as a flux (g H2O/cm2/s). For example, if the stone is fluxing 0.1 g H2O/cm2/30s, that could be a substantial amount of water in some cases.

TXCraig1 · « **Reply #44 on:** May 19, 2015, 01:07:26 PM »

Quote from: CDNpielover on May 19, 2015, 12:07:51 PM

IMO these results support the hypothesis that stones absorb moisture. The stone absorbed 0.1 g while in the oven, that evaporated in 30 s. You've been thinking of this as a problem of total stock, when instead you should be thinking as a flux (g H2O/cm2/s). For example, if the stone is fluxing 0.1 g H2O/cm2/30s, that could be a substantial amount of water in some cases.

I don't think that conclusion follows. First of all, no liquid water is coming out of a pizza. This was an intentionally extreme example. I dropped 5ml of room temp water in a spot about the size of a half dollar. The next set of experiments is far more relevant particularly when taken together with the first. When a pizza was baked on the stone, the weight of the stone went down 1.4g loosing 14X more moisture in the stone than the stone gained when 5ml water was placed directly on it. Next, when 5ml of water was placed on the stone and a pizza baked on top of the water, the stone gained the same 0.1g as when the the water alone was placed on the stone - ergo, it would seem that significant amount of moisture is not being absorbed by the stone from the pizza.

David Esq. · « **Reply #45 on:** May 21, 2015, 04:11:28 AM »

Craig, "it would seem" that there is another test to be conducted. Make 2 pounds of dough. Evenly divided it. Shape and place 1/2 on the cold stone and 1/2 on a solid non porous surface. Keep the dough side by side and wait. Then weigh the dough.

Maybe the results show the stoned dough weighs less in which case "it would seem" that the porousness of the stone impacted the dough.

But weigh the stone before and after to check.

Maybe the results show no difference in weight which would seem to mean water removal was not facilitated by the porousness. On the other hand we are not talking about a lot of water here. It would seem that the water on the surface is what we are talking about and, that the surface water may actually weigh too little to measure with a home scale.

David Esq. · « **Reply #46 on:** May 21, 2015, 04:12:33 AM »

By the way, in the name of mad science, you are going to get an award here for thoroughly investigating.

Crispy Please · « **Reply #47 on:** May 21, 2015, 04:56:18 AM »

Porosity aside, can someone explain how liquid water, which vaporizes at ~212F, can be absorbed by any unconfined mass that is heated to and kept at 500F-1000F?

-Crispy

norma427 · « **Reply #48 on:** May 21, 2015, 07:32:26 AM »

Craig,

I really don't understand, but think when I bake on a stone that is well seasoned (in my deck oven) the pizza seem to bake better than when baking on parts of the stone that are not well seasoned.

Norma

David Esq. · « **Reply #49 on:** May 21, 2015, 07:44:38 AM »

Those may be assumptions that do not occur throughout the entirety of the bake. Immediately after launch the surface of the stone comes in contact with moisture and is covered by an insulating blanket of dough that continues to cool off that surface. The water absorbed, if any, might later be expelled. Again, we may only be talking about a percentage of water on the bottom surface of the dough, so the quantity need not be great. Moreover, water does not instantly vaporize at 212 else a pot of boiling water would last no longer than a moment.

So, between the slow conversion from water to steam and the potential temporary cooling of the stone surface when covered by the damp blanket (or moisture ladened dough) it seems possible to have moisture transferred to a porous stone that is initially quite hot.

TXCraig1 · « **Reply #50 on:** May 21, 2015, 02:37:14 PM »

Quote from: David Esq. on May 21, 2015, 04:11:28 AM

Craig, "it would seem" that there is another test to be conducted. Make 2 pounds of dough. Evenly divided it. Shape and place 1/2 on the cold stone and 1/2 on a solid non porous surface. Keep the dough side by side and wait. Then weigh the dough.

Maybe the results show the stoned dough weighs less in which case "it would seem" that the porousness of the stone impacted the dough.

But weigh the stone before and after to check.

Maybe the results show no difference in weight which would seem to mean water removal was not facilitated by the porousness. On the other hand we are not talking about a lot of water here. It would seem that the water on the surface is what we are talking about and, that the surface water may actually weigh too little to measure with a home scale.

We know from people using wood dough trays that enough moisture is absorbed by the wood that the bottom of the dough ball dries slightly. I would not be surprised if cold, porous stone had a similar effect, but not in 10 or even 20 minutes if trying to simulate a bake time. I also don't think you can compare results of tests below and above the boiling point of water.

If there is another test, it would seem that the proposal to cut an Emile Henry stone in half and remarry the two with one side upside down is the most likely candidate.

TXCraig1 · « **Reply #51 on:** May 21, 2015, 02:38:00 PM »

Quote from: norma427 on May 21, 2015, 07:32:26 AM

Craig,

I really don't understand, but think when I bake on a stone that is well seasoned (in my deck oven) the pizza seem to bake better than when baking on parts of the stone that are not well seasoned.

Norma

By seasoned, do you mean darker in color?

norma427 · « **Reply #52 on:** May 21, 2015, 05:48:24 PM »

Quote from: TXCraig1 on May 21, 2015, 02:38:00 PM

By seasoned, do you mean darker in color?

Craig,

Yes, I mean seasoned by darker in color and more worn.

Norma

TXCraig1 · « **Reply #53 on:** May 21, 2015, 05:56:02 PM »

Quote from: norma427 on May 21, 2015, 05:48:24 PM

Craig,

Yes, I mean seasoned by darker in color and more worn.

Norma

That would make sense in light of November's comments in Tampa's thread cited above. The darker surface is likely more emissive and therefore delivering more IR energy to the bottom of the pie than would a lighter colored surface.

norma427 · « **Reply #54 on:** May 21, 2015, 06:18:15 PM »

Quote from: TXCraig1 on May 21, 2015, 05:56:02 PM

That would make sense in light of November's comments in Tampa's thread cited above. The darker surface is likely more emissive and therefore delivering more IR energy to the bottom of the pie than would a lighter colored surface.

Craig,

I see now that makes sense in light of November's comments in Tampa's thread.

I think my regular home corderite stone is also baking better since it is more seasoned since is has somewhat of a darker surface in some places. It must be getting more emissive since I spilled so many things on it from making pizzas.

Norma

TXCraig1 · « **Reply #55 on:** May 26, 2015, 06:40:55 PM »

Another nail it the coffin for this myth: http://www.pizzamaking.com/forum/index.php?topic=37744.0

CDNpielover · « **Reply #56 on:** May 26, 2015, 10:17:12 PM »

Quote from: Crispy Please on May 21, 2015, 04:56:18 AM

Porosity aside, can someone explain how liquid water, which vaporizes at ~212F, can be absorbed by any unconfined mass that is heated to and kept at 500F-1000F?

-Crispy

It doesn't absorb into the mass, it diffuses into the air within the pores, just like it diffuses into the hot air in the oven.

Jackitup · « **Reply #57 on:** May 26, 2015, 10:55:39 PM »

Quote from: CDNpielover on May 26, 2015, 10:17:12 PM

It doesn't absorb into the mass, it diffuses into the air within the pores, just like it diffuses into the hot air in the oven.

From the start of this thread I've felt absorbed is maybe a poor choice of wording. Allowing the bottom to breathe would maybe be closer to the mark with a more porous surface vs a sealed surface. I agree, a stone that's 600-800° is not going to absorb anything but a more porous surface will breathe better and give a more consistantly browned bottom. A sealed one or rather less porous surface will make steam pockets raising small areas of the crust that won't brown as well, paler, and other areas that brown fine or maybe too much. I hope this makes sense. That's the way I think of it anyway, crust can stay in more surface contact with the stone without being steam lifted up in spots. Agree, disagree?

jon

TXCraig1 · « **Reply #58 on:** May 27, 2015, 12:44:52 PM »

Quote from: CDNpielover on May 26, 2015, 10:17:12 PM

It doesn't absorb into the mass, it diffuses into the air within the pores, just like it diffuses into the hot air in the oven.

Obviously it's the pores (the space not the air) where the water could go. However, steam expands as it heats forcing water out of the stone. Of course there will be some amount of water (in the form of steam) in the pores, but do the math, the mass of water that could possibly be absorbed into the stone is less than trivial.

TXCraig1 · « **Reply #59 on:** May 27, 2015, 12:56:31 PM »

Quote from: Jackitup on May 26, 2015, 10:55:39 PM

From the start of this thread I've felt absorbed is maybe a poor choice of wording. Allowing the bottom to breathe would maybe be closer to the mark with a more porous surface vs a sealed surface. I agree, a stone that's 600-800° is not going to absorb anything but a more porous surface will breathe better and give a more consistantly browned bottom. A sealed one or rather less porous surface will make steam pockets raising small areas of the crust that won't brown as well, paler, and other areas that brown fine or maybe too much. I hope this makes sense. That's the way I think of it anyway, crust can stay in more surface contact with the stone without being steam lifted up in spots. Agree, disagree?

jon

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.