The Fresh Loaf

News & Information for Amateur Bakers and Artisan Bread Enthusiasts

Is it worth the energy to heat up a baking stone for an hour?

xaipete's picture
xaipete

Is it worth the energy to heat up a baking stone for an hour?

I was telling a friend of mine about Eric's observations (now, mine too) about how much heat baking stones lose as soon as you put dough on them. She remarked:



I think thermal conductivity may come into play. Some materials transfer heat more easily than others -- You can put your hand into a 500˚ oven without much pain, but if you touch a 500˚ pizza stone, you'll burn yourself, because stone conducts heat differently than does air. So although the stone may lose heat, perhaps (and I'm just guessing) it transfers its remaining heat faster than would a baking sheet, etc.



What do you think? Is it worth it to use a baking stone or not? Does a baking stone transfer heat faster than a baking sheet?


--Pamela

suave's picture
suave

Your friend is wrong.  Thermal conductivity of steel is 20-40 times larger than that of brick and thermal conductivity of aluminum is even larger - 250 times.  But it is not only about heat conductivity, it is also about heat capacity, and the ability of thermal mass to accumulate heat, and since baking stone is typically much heavier than baking sheet it can store much more energy.

xaipete's picture
xaipete

So tell me more, please. Are you saying that I shouldn't be concerned that might baking stone which I heated up for an hour at 500º lost almost 100º after putting a little piece of pita dough on it?


--Pamela

suave's picture
suave

How did you measure that?

xaipete's picture
xaipete

I measured it with an IR thermometer. I measured the stone before putting the piece of pita dough on it and then I measured the stone where the pita had been when I removed it about 2 minutes later. I preheated the oven for about an hour.


--Pamela

dghdctr's picture
dghdctr

Suave is right.  Stones lose heat slowly -- not quickly -- at least in comparison with metal.  That's the advantage of having a brick or masonry oven with a stone or composite deck.  The thermal mass is much greater than with a typical pizza oven, for instance, since conventional metal pizza ovens are usually constructed with hollow frames.  Between the greater thermal mass of the brick or stone oven and stone's resistance to heat transfer, if you have that brick oven heated to baking temp, it can take a day or two to cool off completely.  When you open the door to an oven with low thermal mass, it can take 10 or 15 minutes sometimes to recover its prior air temp, but with a brick oven this is most often not the case.


The flip side of this is that the same stone oven would need a day or two of firing just to build up enough heat to be able to bake an entire 8 or 10 hour shift.  I would say that in many cases where a bakery uses its brick or stone oven 7 days a week, it retains enough thermal mass from day to day that when they re-fire the next morning for that day's bake, they often don't need matches to fire the wood. 


Most people that I know who use baking stones don't heat them enough, because they don't like preheating for 1 or two hours.  I'd say 60 to 90 minutes is necessary to ensure good oven kick and adequate browning of the loaf's bottom.


Taking the reading of a surface temperature of the stone does not tell you the temperature of the entire stone.  It is very unlikely that the average temperature of the entire stone lost 100 degrees by placing 4 oz of dough upon it's surface.  The surface temperature may have dipped dramatically, but once the oven door is closed, the stone -- which has still retained an overwhelming percentage of its heat -- will start re-heating the surface of the stone, as well as the air in the oven.


Think about the heat of the earth, especially at its core, which is so hot that it melts rock.  The temperature of the surface at the North or South Pole may be sub-zero, but that doesn't give an accurate measurement of the heat energy trapped inside the globe.  The surface temp just reflects the interaction between the earth's surface at those two places and the atmosphere around them, which is greatly affected, of course, by the presence or absence of radiant energy from the sun.


My apologies to any actual earth science experts who may have winced at my laughable attempt at explaining one aspect of heat transfer.

xaipete's picture
xaipete

OK, what you are saying makes sense. Maybe I'm not preheating it enough. Plus I hadn't thought about the fact that maybe it is just the surface temperature of the stone that is decreasing rather than the entire stone.


At any rate my electric & gas bill doesn't seem too have risen much in spite of the many hours I have the oven on at full bore.


--Pamela

merkri's picture
merkri

So ... a couple of random thoughts:


That 100 degrees of heat energy went into your bread, for one thing. It's not like it was "wasted."


Also, it's important to remember that's the surface temperature of the stone. There's a big difference between the total heat energy in the stone and the surface energy. That difference, in fact, is one reason to use a baking stone, as opposed to a pan, where the difference isn't so great.


Think of the stone as a heat battery. You lose some energy from the stone, but it goes into your bread. You have energy from the air and walls of the oven and your stone, instead of just the air and walls of your oven.


Having said all of that, I can imagine that it would all depend on what type of stone you have: the material, the thickness, etc. Some stones I'm not sure are worth it.


I have a wood-fired brick oven, but the stone in that is not the same as the baking stone for my convection oven. I imagine there's differences across baking stones in their properties. The firebrick in my wood-fired oven is a lot thicker and lighter than the baking stone in my convection oven.


The biggest differences I notice in baking on stone as opposed to not: are the crispness of the crust (crust on stone is crisper) and the time (stone is shorter). I also have this sense, that's hard to describe, that bread in my wood-fired oven (where there's more brick) has a relatively moist crumb for a crisp crust, compared to the convection oven--i.e., it's not that I couldn't get as crispy a crust as the brick oven, but to do that, the interior would dry out more or something.


I don't know. After using stone for awhile, and trying some recipes on a pan, I realized you can still get excellent, excellent bread on a pan. The total amount of heat in the oven makes a bigger difference than the pan versus stone per se (e.g., using an oven that can heat to 700 degrees versus 500 is a bigger difference than the baking surface per se).


 

xaipete's picture
xaipete

True, the energy is not wasted.


--Pamela

jeb's picture
jeb

You may loose 100º of your oven temperature opening the door, but I'd bet that you don't loose 100º of your baking stone temperature. You need to get an IR thermometer to check it out.

arzajac's picture
arzajac

Can an IR thermometer read the mean temperature of the stone?  I think it can only measure the temperature at the surface of the stone, which is not the whole picture.  I suppose the surface of the stone can heat up quicker than the internal temperature.


I think the ability of the stone to retain heat is not the only property that is of value.  The fact that it is very able to conduct heat can transfer heat to the dough, but it can also transfer the heat *away* from it, too.


That explains why the bottoms of my breads (especially the sweet, oil-enriched ones) take a lot longer to burn when I cook them on a stone in comparison to cooking them on a sheet pan.  I reckon the sheet pan can conduct the heat from the air (convection) and the direct heat from the element (radiation) very efficiently to the dough, which causes its bottom to burn.

sphealey's picture
sphealey

=== Can an IR thermometer read the mean temperature of the stone?  I think it can only measure the temperature at the surface of the stone, which is not the whole picture.  I suppose the surface of the stone can heat up quicker than the internal temperature. ===


You are correct:  the IR thermometer is measuring the infrared waves emitted from the surface of the stone.  Clearly these bear _some_ relationship to the overall energy content of that stone, but on the other hand you could turn on the broiler for 3 minutes and get a much higher surface temperature that wouldn't be the average temperature or indicative of the energy content.


People who are interested in the temperature of their brick ovens drill holes at various depths in the refractory and insulating material and cement thermocouples into them to get the temp at various depths into the energy-storing components of the oven.


sPh


Note the word "emit" above; hence the term "coefficient of emissivity" you might find in the instruction manual for your IR thermo.  The first IR thermometers had a dial to set the emissivity of the target so that the measurement would be correct.  Low-end household IR thermos are usually set for the average emissivity of typical household materials (around 0.95 IIRC).  If yours does not have a setting for emissivity of the target you might have to apply an adjustment factor (available from the manufacturer) when shooting your stones.

SylviaH's picture
SylviaH

You can take out heat from the oven that you put in.  This saying is used a lot when firing up a wfo for baking.  Meaning the longer your fire your oven the longer you are going to be able to bake in it..  This how a wfo oven works.  So I would think a stone in your home oven would work the same.  Your IRT is only going to measure the outside temperature.  With a wfo oven the floor, roof, sides all have different temperatures in the beginning..so the oven needs time to let the heat balance out before baking.  The floor will cool where a pizza has been cooking..but retained heat will bring the floor  back to the hotter temperature.  So I would think the same would be for your oven stone.  I pre-heat one hour when baking with my stone or stoneware/la cloche.  This way I can make several pizzas indoors on my oven stone by only waiting a few minutes or putting the pizza's in a little different spot each time..I have two large stones that cover the complete shelf. 


Here is a picture of thermal mass in a pizza oven  http://www.fornobravo.com/pizza_oven_selection/thermal_mass.html  hope this link works..


Sylvia

xaipete's picture
xaipete

That's a good chart and site with a lot of information about thermal mass. Thanks for posting the link to it. It is helpful.


This is turning out to be a good discussion from my point of view. I can also now see why people like those Hearthkits.


--Pamela

ehanner's picture
ehanner

Every bit of energy that is not used to actually bake the loaf is--wasted. All the btu's used to heat the oven and all the btu's remaining after the bread is done. And if you are running the AC to combat the heating of the house in the summer, that also is wasted energy.


You can argue that the crust is crisper, the crumb is softer or any other property of the bread. You can't say it's necessary for baking. In the case of a WFO, folks try to use all of the residual heat for other tasks. I suspect that comes from knowing how hard it is to gather fuel.


Some electric ovens power the top elements during the baking cycle. This in effect creates the same heat ratios found in a earthen oven.


Eric

merkri's picture
merkri

<i>Every bit of energy that is not used to actually bake the loaf is--wasted. All the btu's used to heat the oven and all the btu's remaining after the bread is done. And if you are running the AC to combat the heating of the house in the summer, that also is wasted energy.</i>


Well, it depends on what you mean by "wasted."


You're right in the sense that if you want to bake bread in the absolutely most energy efficient way, a stone is probably totally unnecessary. But that's a different criterion.


But if your oven is heating up anything in your house, then it's not very energy efficient to begin with--because it's not insulating very well. You probably shouldn't be heating it to 500 degrees either.


A stone is not necessary to bake great bread, but it does change the characteristics of what you get. It all depends on what you're looking for.


 

subfuscpersona's picture
subfuscpersona

...of which I am *definitely* one.


I've also pondered the question posed by xaipete


Many bakers here use baking stones and most reputable books on artisan bread uniformly recommend them. However, preheating instructions (initial heat setting, length of time to preheat) are all over the map.


Some bakers here, both those who use baking stones (and those who do not) are concerned about energy costs. We want to get good performance from the baking stone we've bought, but not spend unnecessary $$$ for a lengthy preheat.


I'd really like to hear from experienced, practical home bakers who make artisan breads about the *lowest* temp and preheating times they've found effective for a "lean" (primarily flour, water, salt, yeast) boule or batard with an approximate pre-baking weight of 1-1/2 pounds, containing no more than 20% whole grain and with a hydration of no more than 80%. I'm not trying to be picky by stating the above forumula but I think this establishes the parameters of what many here make as their daily bread.


I'm looking for a good oven spring, good grigne and a thin crackly crust. I don't want the dough to spread out - I want it to spring *up*.  Can you help me? In order to help me, do you need more information?


 


 


 


 

xaipete's picture
xaipete

Maybe the question ought to be: Who doesn't preheat at 500º for one hour?


That's what I've been doing and I get good results.


--Pamela

suave's picture
suave

Much depends on the size of the stone.  The thicker the stone, the longer it should be heated.  I use half-inch tiles, and from experience I know that heating them longer than 30-35 minutes does not help.  With thicker stone an hour would be a reasonable time.   As to the temperature, the advice I heard is to heat to your baking temperature +50F.


On the other hand, things you're looking for depend not only on how long was the stone heated, but also on the shaping, correct proof, and slashing technique.

Pablo's picture
Pablo

Hi Pamela,


You might try your pita bread IR reading experiment at 30 minutes preheat, 1 hour, 1 1/2 hour, 2 hours.  Does it change?  Then you can try finding out how fast the surface temperature recovers at various preheat times as well.  Oh yeah, and maybe bake some bread :-)  I'm very interested in these experiments myself.  Tomorrow I'm picking up a new stone, and the IR thermometer, and a pair of Kevlar gloves among other things from a shipping/receiving depot in the States.


:-Paul

SylviaH's picture
SylviaH

You if want to save the most energy then maybe it's better to just do all the baking you can in one day?

suave's picture
suave

That's why they had communal ovens.

xaipete's picture
xaipete

Good point but what would I do the rest of the week?


--Pamela

dghdctr's picture
dghdctr

Bakers in Europe (in the old days) would sometimes accept clay pots full of stew or pans with roasting meats from their customers for a nominal charge.  Otherwise, after the bread had been baked that day, the oven would have stood empty even though it was hot.  This worked well for all concerned.  Also, Pumpernickel bread was actually created with the idea of utilizing the declining heat of the oven overnight -- Jeffrey Hamelman writes about it in his book.


We can roast peppers, bake biscuits for breakfast, make cookies, or bake/roast other things in the oven while we pre-heat it.  Eric is right in that if we don't use the energy in an empty oven, we are wasting some of its potential benefits.  Of course, you need to re-think your entire cooking day if you want to be efficient in oven use that way.  My gut tells me that people prefer convenience over being that organized.  If the pre-heating seems wasteful despite its necessity for good bread baking, they'll cut the pre-heat time and then wonder why their bottom crust is never as brown as the top.


--Dan DiMuzio

xaipete's picture
xaipete

Thanks, Dan. In order to be "green" I'll try to plan to be in the kitchen cooking all day now instead of just half! No, really. I enjoyed reading this little bit of baker's history.


--Pamela

flournwater's picture
flournwater

Even though I do religously preheat my stone in the oven, I take a broader view of its used in baking my bread.  The heat from the stone helps brown the bottom of the loaf, but that's really secondary to my greater interest in using it for break baking.  I can brown the bottom of my bread loaves using a sheet pan, but it doesn't "hold onto" heat the way the stone does.  So the stone's primary purpose in my oven is to help maintain a more constant temperature throughout the baking cycle. 


I recognize that, in the mind and experience of the professional baker, I may have it backwards.  If that's the case I'm eager to learn where I made the wrong turn.  But in my VERY limited experience, that's the conclusion I've drawn.

LindyD's picture
LindyD


Maybe the question ought to be: Who doesn't preheat at 500º for one hour?



I don't.  I preheat the oven to the temp stated in whatever recipe I'm using (generally 460F).  My oven has a preheat function and beeps when the designated temp has been (allegedly) reached.  I use two oven thermometers, so I go by those.  It takes around 30-35 minutes to reach 460F (I have a newer, very well insulated, natural gas stove).


My baking stone lives in my oven.  It heats up with the oven, but is really there for the ride until it receives the bread.  I see it more as a tool to use in baking my bread rather than a factor in determining when I load the bread.    I really don't care what the stone's exact temperature is, so long as it is hot (which it is).    The bottoms of my loaves are always nicely browned  - never burned - and I like the results I get with the stone much better than the results I was getting with a metal baking sheet.

Paddyscake's picture
Paddyscake

My stone resides in my oven also. I preheat to 500 and my oven functions as Lindy's with the indicator beep. My oven doesn't take much more than 20 minutes to reach that temp.


I just baked this bread this weekend. Not a stellar loaf, but you can see the crust. Well browned, top and bottom. My picture taking leaves something to desire. It isn't burnt.


Betty

xaipete's picture
xaipete

Subject 3 is Betty who preheats to 500º but loads her loaves when the oven beeps after 20 minutes. I'm not really sure if Betty's oven is really at 500º (I doubt it), but for what ever it is worth.


--Pamela

Paddyscake's picture
Paddyscake

I have been fortunate to have fairly decent results. I've provided some pictures, showing what I've baked.

dghdctr's picture
dghdctr

I have to ask -- and I'm not being snarky, just curious -- what are the white spots interspersed with the dark crumb in the loaf that's pictured?


--Dan

Paddyscake's picture
Paddyscake

Hi Dan,


That was my attempt at Shaio-Ping's Goji berry & spinach bread. I decided to use grated zucchini instead. I could not incorporate the berries and zucchini in the dough. It just sort of slid around it. That was the best I could do, but it still tasted great.


Betty

xaipete's picture
xaipete

Thanks, Lindy. So in our survey we have one person who only heats to 460º for 30-35 minutes.


--Pamela

LindyD's picture
LindyD

That's correct only as it applies to a particular formula I'm baking.  If a 500F oven is called for, I'll preheat to 500F.  The magic number is what the recipe says the bread should be baked at.


All my bread books advocate baking on a stone, but not a single recipe says "preheat the oven until your baking stone reaches XXX degrees F/C."


My parents advocated waste not, want not.  That's a good philosophy to follow.

xaipete's picture
xaipete

But don't many of the recipes say to preheat the stone for an hour? When you preheat to 500º, do you load the loaf as soon as the oven beeps?


--Pamela

LindyD's picture
LindyD

Gee, Pamela, I don't recall any bread recipe I've baked stating that the baking stone should be preheated for an hour.  I'll check again when I get home tonight, but offhand, I don't think I've ever seen that suggested....except at TFL.


When I preheat to any temp, the preheat beeper may go off but I don't load the oven until the oven thermometers confirm the required temp has been reached.


Maybe I'm missing something, but if the oven is at the desired temp when the bread is loaded to the stone, the stone is hot.  The bread gets good oven spring and a nice bold crust, top and bottom.


What's the alleged advantage of preheating the stone for an hour?

xaipete's picture
xaipete

I'm pretty sure PR's books tell you to preheat for an hour and there are others too. Did you read Dan's post below?


http://www.thefreshloaf.com/node/12995/it-worth-energy-heat-baking-stone-hour#comment-77409


--Pamela

SylviaH's picture
SylviaH

The oven is probably just measuring the outside temperature of the stone and not the inside..thermal mass of the stone...we have been having a lot of fun measuring heat with out new instant read IRT and thats what they do..something can be 450 on the surface but not internally!  There probably is enough heat retained to do a loaf..and then when removed letting the oven heat up a longer giving the stone time to recover works for the next load!  If I do several pizza's in my oven..it reguire's full temp..550 and pre-heat time of at least 45 minutes..or the stone cooks each pizza taking a little longer...they take the heat right out of the stone fast!  I like my pizza's to cook fast and hot..only taking a few minutes.  I even notice this in my WFO when it's heated up to over 700F if I set a pizza in the same spot..it takes recovery time for that heat to come up from the interior of the floor that was put there by a longer firing of the oven..I can see not only on the crust but the time it takes it to brown..you only get the heat out that has been put in..meaning longer firing time to get that accumulated thermal mass.   


Sylvia

dghdctr's picture
dghdctr

If anybody (including my friend Lindy) wants to bake on a stone heated 30 minutes, or cold stone, or no stone -- whatever -- and they're happy with the results, that's fine.  Who can tell somebody whose bread is already excellent that they need to change anything?


I've had lots of experience with dozens of different stones in different ovens.  Anything that's 1/2 inch or more usually needed at least an hour -- sometimes 2 hours -- to be hot enough to brown the loaf's bottom sufficiently before the upper crust was caramelized.


I suppose that thinner stones, those with less mass, or stones that just vary in their composition from what I've used could have different heating requirements.  The one I'm using now -- which I purchased from Williams Sonoma -- never seems to get hot enough to crisp the bottom of my super-hydrated Pugliese loaves.  I'm starting to think that one of their buyers went to some professional composite stone maker and purchased the expensive stuff which loses heat very slowly -- which means it would also gain it just as slowly.


If Lindy says she needs only 30 minutes of pre-heating to bake a loaf of bread properly, I don't doubt that she's right about her oven, or her stone, or her experience with them.  Apparently, from what I'm reading in these posts, people's experiences with pre-heating stones are all over the place, and it may be hard for us to generalize accurately about them.


--Dan DiMuzio

xaipete's picture
xaipete

I don't want to add fuel to the fire (i.e., heat my stone for longer than is necessary), but now that you mention it, Dan, I'm sure I'm not heating mine up long enough (only 1 hour) because my bottoms aren't getting brown enough.


I'm going to try 2 hours on my next bake; I bet it will improve the bottom crust.


--Pamela

LindyD's picture
LindyD


Sourdough (parchment is used between the bread and stone).

dghdctr's picture
dghdctr

Lindy -- would you tell us what brand of stone you're using?  I want to get it.


--Dan

LindyD's picture
LindyD

It's a 14 x 16 clay baking stone purchased through Amazon - sold by Cooking.com.


Here's the Amazon link


@Betty and Eric....thanks for your comments.  That's old reliable (Hamelman) North Woods sourdough.

Paddyscake's picture
Paddyscake

Lindy, this is one I haven't seen. Is this in "Bread"?


Link is to my 14x16 stone, also bought at Amazon on Floyd's recommendation: I've been very happy with it for the past 3 years.


http://www.amazon.com/Old-Stone-Oven-14-Inch-16-Inch/dp/B0000E1FDA/ref=sr_1_1?ie=UTF8&s=home-garden&qid=1248491887&sr=1-1


Betty

LindyD's picture
LindyD

Hi Betty,


Sorry for the confusion.  It's the Vermont sourdough.  Jeff Hamelman wrote he calls it that because his levain lives in Vermont.    My levain lives up here in the north woods of Michigan, so I call my bread North Woods sourdough.

Paddyscake's picture
Paddyscake

OK..yes, I have made the Vermont sourdough,but it's been a while. I guess I must make Willamette Valley sourdough. I've favored Thom Leonard's, but maybe I need to try the Vermont again.


Betty

SylviaH's picture
SylviaH

LindyD, Thanks for the link...My stone looks nearly 2 to 3 times thicker..how thick is your stone, not including the feet? I just measured my stones that came with my oven.. one stone measures 131/4X101/2- 3/4"thick there are two stones that fit together to cover the complete oven shelf made to hold them.


Sylvia

LindyD's picture
LindyD

Hi Sylvia - my stone is half an inch thick.   The numerous feet underneath the stone are about half an inch (can't measure precisely right now because I just finished baking bagels).


I kept track of time and temperature this morning for the bagel bake. Oven temp was set to 500F.  When the preheat beeper went off after 15 minutes, the oven thermometers read 450F.  When I looked again, eighteen minutes later, the oven temp was 500F, so it took 30-33 minutes to get to 500F. 


No idea what the stone temp was, but the bagels were nice and brown, top and bottom.

ehanner's picture
ehanner

Wow Lindy that is a perfect cross section of a sourdough loaf. I love it!


Eric

Paddyscake's picture
Paddyscake

As I said before, it works for me also. I started out preheating for an hour and gradually kept cutting back and found it really didn't make a difference. I took the advice given and went from there. It works for me, so that's all that matters.


Beautiful slice of bread Lindy!


Betty


 

xaipete's picture
xaipete

Just happened to notice today that Hamelman recommends 45 minute preheat for stones (pg. 89).


--Pamela

LindyD's picture
LindyD

Page 39 of the BBA.


I'm ten minutes off, but it still works out fine in my oven.

Soundman's picture
Soundman

I'm right with LindyD. I don't preheat to 500 dF and I load my first loaf within a couple of minutes of the beep indicating temp (450 dF) reached. The bottom of my loaves look just like the tops and sides in color. Oven spring is enough to create ears and bloom. The second loaf does the same, in spite of the more comprehensive pre-heating it receives. And BTW I have a 3/4 inch thick stone.


The bread results I get are much better with the stone. I can't measure the energy used with stone and without, but my gas bills are the same either way, and I guess that's as good a guide as any.


David

mkelly27's picture
mkelly27

I am right there with Lindy also.  My stone also lives in the oven and when the oven is preheated then the stone is preheated as well.  It may not be at the same temp as the oven right away, but it is nearing it on the inside.   It's not like placing a cold stone in a hot oven, and preheating the stone that way, the stone heats with the oven.


14"x16"x5/8" from cooking.com.

ericb's picture
ericb

I love this site. Where else can you get an in-depth scientific discussion about thermal transfer in the same thread as the history of pre-industrial communal ovens? And even some practical advice thrown in for good measure!

MaryinHammondsport's picture
MaryinHammondsport

I compromise and preheat for 30 minutes after the oven reaches temperature, before putting the bread in. I preheat only to the temp. required by the bread, not to 500 degrees.


I have to use an oven thermometer, as opposed to depending on the oven controls and my general feeling is that when the controls says it is up to 460 degrees, for example, the stone really is not. Thus, the extra 30 minutes or so.


I think there are so many variables with regard to ovens that each of us has to do what works for us.


I keep saying that I need to get this oven fixed, but getting the company's repairman out here to the boonies is such a hassle that I put it off. So far we are making it, though I have to pay much more attention that previously. Maybe that's a good thing!


 

LindyD's picture
LindyD

I haven't baked anything from the BBA for some months, but I do think PR may have advised to preheat the stone for an hour when baking the ancienne baguettes.  I just don't recall whether I followed that advice.  Will have to wait until I get home to see if I can find any texts which mention an hour preheat time for a stone.


I read Dan's post, but I get good oven kick and more than adequate browning of the loaf bottom without a 60-90 minute preheating of the stone.  So why waste natural gas (and money) for such a long preheat?


Like Soundman, I see no difference in the result when doing consecutive bakes, where the stone has the benefit of being continually heated in the oven during the preceding bake.


To take the topic to the other end of the spectrum, I recall rearding earlier posts about how wonderful bread came out of the oven with no preheating and a cold stone.  I never had the courage to try that.


 


 

Marni's picture
Marni

For those who live where it's HOT (I'm in S.CA) and want to save energy, how about setting the stone out in the sun for an hour or so, loading it the oven and then preheating for a shorter time?  I make this suggestion partly in jest, but hey - it might work!


This has been a great thread! Thanks Pamela.


 


Marni

xaipete's picture
xaipete

If I lugged my stone out into the sun and was lucky enough not to break it, my little dachshund would no doubt stretch his tiny body out on it. I've never seen a dog that liked heat as much as my little hot dog.


--Pamela

Soundman's picture
Soundman

My little dog loves to sun himself on the granite flagstones, wearing a fur coat no less! Go figure.


David

SylviaH's picture
SylviaH

In Las Vegas you could actually fry an egg on the stone...though in Vegas they use the word..sidewalk!  Glad I live in S.CA now..it's hot but not as hot as Vegas!  There you could put a solar oven to great use!  


Sylvia

LindyD's picture
LindyD

I wonder if that makes any difference in the amount of time it takes to preheat an oven and/or stone.

xaipete's picture
xaipete

Electric, Lindy.


--Pamela

Soundman's picture
Soundman

Maybe that's the biggest variable here, gas or electric. My oven uses NG.


David

longhorn's picture
longhorn

What the stone does is temper the oven and speed the heating of the dough. This is going to be long so be warned!


I have a wood fired oven that I heat for about 2 1/2 hours with a big fire to heat load the oven. When I remove the ashes and coals and lightly mop it the temperature of the hearth cools to about 650 F. The dome will be around 950. I then close it up for an hour and let everything stabilize and the temp of the surface of both the dome and the hearth will be around 550 (yes the dome is slightly hotter).


I load the bread (about 15-18 pounds) at about 550 and spritz the interior with water. This will cool the surface of hearth and dome significantly (I haven't checked the temp but under the loaves is probably 400 or so, maybe less. The air in the oven will be pretty cool - probably 250 or so. But the heat deeper in the walls and hearth flow back to reheat the air and bake the bread. 50 minutes or so later when I remove the bread the hearth and dome temp will be around 475. (It will be hotter if I burn longer before I begin the bread - but I ususally only do one batch.)


The stone in your oven does the same thing - but not as well for it is very light compared to a WFO, but it helps reheat the air and gradually (think gracefully) raises the temperature at the bottom of the loaf as heat seeps back to the oven.


When you put a loaf in an oven on a cold metal pan where does the heat come from that warms the pan and the bread? From the air only and most of that heat comes from the heating element (or flame). What do you think the temperature is in an oven when you first begin baking? Close to 212 (due to the steam you release from your steam system). And don't forget a lot of the hot air in the oven BEFORE you put the dough in left while you loaded the oven. So, finally, which oven should get hot faster - one that is a naked oven or the exact same oven with a stone preheated to baking temperature. The answer is obvious!


If the goal was to heat the bread as fast as possible we would bake on thick sheets of preheated steel. But you would burn the heck out of the bottom of the bread for the heat would rush to the bottom of the loaf (good conductivity!) and it would be a disaster. The heating rate is important! You want it slow enough (and with enough humidity) to let the crust gelatinize and the gases and some of the alcohols in the loaf to come out of solution (vaporize) and expand to lift the loaf. Too fast and the crust will set too fast and the results will suffer. Too slow and gases will escape excessively and the results will suffer. That is why these "standards" have been arrived at - they have the right "heat profile' characteristics to give a good loaf.


Short cycling a stone (i.e. not heating it through and unless it is REALLY THIN 20 minutes is NOT enough) simply means the stone won't temper the oven as much and the rate of temperature recovery will be slower. Not a disaster. but it probably means you will get better loaf volume and oven spring if you heat the stone longer. Having your oven say the oven is at temp only means the air reached that temp. Yes it takes a bit longer than if there were NO stone in the oven but not a lot. But at that point the center of the stone is still pretty cool. I have a Hearthkit stone for my indoor kitchen and it has a thermometer slot that allows one to get the temp (sort of) IN the center of the stone. The Hearthkit is really thick - about an inch and it takes about 30-40 minutes for the thermometer to reach temp (i.e. have the stone fully heat loaded) AFTER the oven says it is at temp!


Hope some of you find that useful!


Jay


 


 

xaipete's picture
xaipete

Thanks, Jay, for your excellent post. What you say makes a lot of sense. I'm anxious to see what happens to my bread when I really get my stone hot.


--Pamela

longhorn's picture
longhorn

If you want to waste some dough, try putting a loaf of bread in your HOT oven on a COLD stone (it shouldn't break but...). You will end up with a loaf with a totally to almost raw bottom. By the time the crust is baked the heat will probably just be beginning to really reach the bottom of the bread.  The loaf should be very dense (not enough heat getting into it to give proper expansion). A stone that is only marginally heat loaded should seal the bottom but could easily give similar results and a very pale "doughy" bottom. Obviously the paleness and underdoneness of the bottom goes away as the stone receives longer heating.


There may well be some breads and some ovens where an underheated stone is good but????


I am guessing a bit here, but I suspect the advantage of "overheating the stone" to 500 and then turning it down is that it compensates a bit for the fact the stone is not very big compared to a WFO or the oven volume it is trying to heat. Thus having it extra hot lets it put a bit more heat into the oven and elevate the temp of the oven a bit faster than if it had been heated to say 450. And that seems to be especially helpful on wet, artisanal loaves that cool the stone more than a smaller, stiffer dough might.


 Jay

xaipete's picture
xaipete

I don't want to waste good dough, but I might try an experiment cooking multiple loaves at different times, e.g., 30 minutes, 1 hour, 1 1/2 hours.


--Pamela

longhorn's picture
longhorn

The challenge will be having them equally proofed. I will bet the difference between 30 and 60 minutes of heating will be somewhat subtle but visible to our critical bakers - assuming identical loaves and proofing (again, a bit denser, probably a tad "raw" on the bottom compared to the crust, less rise). I doubt you would see a difference between 60 and 90 minutes. The stone should be loaded (or very close) in an hour and any differences should be very minor.


If the 30 works, try 15!  At some point it will not work. I guarantee! :o)


Jay

merkri's picture
merkri

Another experiment to try is to preheat the stone for, say, 60 minutes, put the loaf in, and shut off the oven completely. I'd be curious what would happen with that.

Pablo's picture
Pablo

Calvel warns against moving the loaves as they bake as it is "one of the major causes of (bottom) crust burning".  Presumably this would come about from moving the loaf to an area of the stone that had not lost heat to the loaf already.  I try to be careful about repositioning the loaf to the same place when I rotate them midway through baking (when I remember to do that).


:-Paul

SylviaH's picture
SylviaH

Hi Paul...I can see where you are right about that because...I do just the opposite when making several pizza's so I have a fast cooking pizza and perfect crust.  I have to have the oven and stones up to full 550F. one hour pre-heat time works great!  This way I can place one very large pizza..it will be completely crisped and deeply browned bottom and crust in no more than 7 mins. I can definately see the difference in time and temp. change on the stone when cooking the pizza..so I place it as much off the same spot where the last pizza cooked..this way the temperature is regained back and the stone has time to draw that inner retained heat back to the surface.."stabilize" it's called in wfo cooking!  I have another smaller counter top convection,bake,broil, rotisseri,slow cook, you name it... oven that has a thinner pizza stone that came with it...the first pizza comes out okay..it only heat to apx. 450..the next pizza the crust is not as good..the stone has lost to much heat from the first pizza..it requires more pre-heat time.  Pizza always tells me what's going on with the stone!


Sylvia

longhorn's picture
longhorn

Good Question about turning off the oven. It MIGHT work but I fear the mass of the stone is too small compared to the volume of the oven. I would certainly welcome hearing about your results if you try it.


One of the things you learn with WFOs is that you can trade time for temperature (to a substantial extent). IF the stone holds enough heat to get the oven in the 375 range it may work.


RE: moving bread, once the bread starts to dry out it can burn pretty easily and moving it to 450 stone with it dry is a problem.


Good luck!


Jay

SallyBR's picture
SallyBR

I have not read all the replies, but thought it is interesting that I just posted about NOT heating the oven for one hour, and getting excellent bread.


 


I know I am in the minority, but I refuse to use so much energy when I get excellent bread by heating my oven for much shorter time.


For instance, baking at 440F with a pre-heating of TEN minutes using a clay baker, gives me a loaf of great bread that was not too different from a bread baked on stone heating the oven for 45 minutes at 480F (I don't have side by side pictures, you will have to trust my word for it).


I simply cannot bring myself to keep an oven on for one hour = imagine if every household in the planet wanted to do that on a daily basis  :-) 


see page two of this link


http://bewitchingkitchen.wordpress.com/2009/07/27/the-bread-we-love/


 


I thnk that for pizzas the maximum heat possible at the bottom is important. 


In that case, I have been using the outside grill as an oven, adding quarry stones on it. Since I've started doing it, I never fired my oven again for pizza. The grill gives a much higher temperature, the house is not heated up, and again, no need to keep the grill on for one hour before making the pizza.


 


 

mixinator's picture
mixinator

Here is a thought about gas vs. electric ovens.

In an electric oven, when the thermostat turns off the current to the heating element, the heating elements remain hot for quite some time afterwards, acting in effect as a thermal flywheel.

When the flame in a gas oven is turned off, the only things radiating heat to the food are the interior walls. A baking stone can act as a thermal flywheel in lieu of the turned-off heating elements of an electric oven.