Steam injection oven – Keller style – safe?

[pbear]

If baking bread in a covered pot, you should use a spritzer. It's a small room and easy to generate enough steam with a few spritzes (plus the dough adds moisture). Whereas the ice method depends on direct contact with a skillet or grill pan, It's intended for steaming the whole oven.

[OliverB]

good info, just getting back to this thread. I'll try the cast iron pan I think. I also have a recipe somewhere to bake bread in a dutch oven in my Big Green Egg, at the Eggfest somebody made that and it was really good. Have to try that when it gets a bit warmer outside.

[Paul Kierstead]

Has anyone ever tried running a small metal tube into the oven via the oven door and injecting continuous steam for the first few minutes?

[EnriqueB]

I just got Keller's Bouchon Bakery book and in the bread section he suggest to put a tray with rocks and a fat chain on the bottom of the oven, then when you put your dough on the backing stone he appears to suggest using a super soaker or something like that to add a lot of water and slam the door shut.

Now, that idea certainly can work, but isn't that really dangerous? Seems he has a glass door on the oven (like mine) though it's not quite clear to see. Get some cold water on that super heated glass and you will have a great big expensive and potentially quite dangerous mess, no? Same with the baking stone, if you don't aim well and get water on that, won't it shatter?

Has anybody here tried this method? I kind of like the medieval look of rocks and chains in there, but I don't want to risk oven or burns either.....

I use the tray with rocks as well as a mist sprayer when baking bread in my electric convection oven and never had any problem with the glass. This was a trick I learnt in a course from the best-known home bread maker in Spain and I know many people that also use it. No problem has been ever reported by any of them, that I know of.

[Crouton]

Where do you keep the rocks and chains when not in use? Seems like a PITA to drag all that out each time you make bread, no?

[OliverB]

maybe I'll try it sometime. Just seems fun in an odd way. I'd probably just leave the whole thing in the oven at other times, I don't use it all that much. If in the way for something, pull out that tray and set it somewhere for the time being, then back in the oven. I generally leave my pizza stone in there as well.

[EnriqueB]

The stones are always on a steel pan devoted only to that.

[Syzygies]

What purpose do chains and rocks have over a simple pan of water? Seems squirting a water gun over a pan fulll of rocks wouldn't produce all that much steam, or at least a consistent supply once the initial spray evaporates off.

Rocks (and chains, I guess) can get a lot hotter than water and therefore can store a lot more heat - which the water can use to change phase from liquid to gas (steam). The amount of water will limit the amount of steam and the size/amount of stone will determine how much energy is available for the conversion.

I've been waiting to reply to this while I made various experiments.

Here's a great link on the physics:

Counting Calories

http://www.mansfieldct.org/schools/mms/staff/hand/countingcalories.htm

The key numbers: It takes 80 calories to thaw a gram of ice, 100 calories to bring that gram to the boiling point, and a whopping 540 calories to then turn that gram of water to steam.

Different sites discuss the relative heat stored by different substances. Cast iron holds about 13% as much heat energy as water, degree by degree. Stones hold about 20% as much heat energy as water.

So if one runs the numbers, a 15 lb cast iron skillet at 500 F will boil off around 250 ml of water. It makes scant difference whether one uses hot tap water, or boiling water, and the convenience of using ice cubes isn't that inefficient. Of course, one will eventually boil off more water, but once the stored heat is released as steam, the eventual rate will depend on the rate at which one's oven can reheat the pans/chains/rocks involved. Slowly. For an initial burst of steam one can basically ignore this later effect.

Bouchon bakery is proposing rather more mass than one 15 lb cast iron skillet, and these numbers make it clear why. However, stainless steel is rather expensive in any form (chains, balls) and substitute metals such as galvanized can release poisons; they're avoided in the barbecue community. Rocks can explode. Cast iron would appear to me to be the most cost effective and easily handled/moved form of thermal mass for this purpose.

Pictured is the first of these skillets, in a Komodo Kamado ceramic cooker (http://www.komodokamado.com/):

Lodge Logic Pre-Seasoned Skillet (15-inch)

http://www.amazon.com/Lodge-L14SK3-Pre-Seasoned-Cast-Iron-Skillet/dp/B00063RWUM

Lodge Logic L17SK3 Pre-Seasoned Cast Iron Skillet, 17-inch

http://www.amazon.com/Lodge-L17SK3-Pre-Seasoned-Skillet-17-inch/dp/B00063RWVG

Based on these calculations, I'm planning to buy a second 15 inch skillet to stack on the first for my ceramic cooker, and I'm considering a stack of two 17 inch skillets on the floor of my indoor oven. It looks pricey, but not compared to swapping ovens. The thermal mass can only help for most applications, so they'd just live there. The stack of two buys me the liberty to use ice (shown here to be only slightly less efficient), which is safer indoors, and less likely to spatter and dampen my fire outdoors.

(I wish there was a term of art for forum responses of the form "I don't use sous vide and my food comes out fine!" Of course it does! Such responses don't give credit to commercial bakers who understand this problem far better than any amateur, and consider ample steam worth the trouble. As in, more steam than most of us have ever experienced, making bread for ourselves. If one can't make the comparison, one just doesn't know.)

[HungryC]

What purpose do chains and rocks have over a simple pan of water? Seems squirting a water gun over a pan fulll of rocks wouldn't produce all that much steam, or at least a consistent supply once the initial spray evaporates off.

Rocks (and chains, I guess) can get a lot hotter than water and therefore can store a lot more heat - which the water can use to change phase from liquid to gas (steam). The amount of water will limit the amount of steam and the size/amount of stone will determine how much energy is available for the conversion.

Komodo-steam.jpg

I've been waiting to reply to this while I made various experiments.

Here's a great link on the physics:

Counting Calories

http://www.mansfieldct.org/schools/mms/staff/hand/countingcalories.htm

The key numbers: It takes 80 calories to thaw a gram of ice, 100 calories to bring that gram to the boiling point, and a whopping 540 calories to then turn that gram of water to steam.

Different sites discuss the relative heat stored by different substances. Cast iron holds about 13% as much heat energy as water, degree by degree. Stones hold about 20% as much heat energy as water.

So if one runs the numbers, a 15 lb cast iron skillet at 500 F will boil off around 250 ml of water. It makes scant difference whether one uses hot tap water, or boiling water, and the convenience of using ice cubes isn't that inefficient. Of course, one will eventually boil off more water, but once the stored heat is released as steam, the eventual rate will depend on the rate at which one's oven can reheat the pans/chains/rocks involved. Slowly. For an initial burst of steam one can basically ignore this later effect.

Bouchon bakery is proposing rather more mass than one 15 lb cast iron skillet, and these numbers make it clear why. However, stainless steel is rather expensive in any form (chains, balls) and substitute metals such as galvanized can release poisons; they're avoided in the barbecue community. Rocks can explode. Cast iron would appear to me to be the most cost effective and easily handled/moved form of thermal mass for this purpose.

Pictured is the first of these skillets, in a Komodo Kamado ceramic cooker (http://www.komodokamado.com/):

Lodge Logic Pre-Seasoned Skillet (15-inch)

http://www.amazon.com/Lodge-L14SK3-Pre-Seasoned-Cast-Iron-Skillet/dp/B00063RWUM

Lodge Logic L17SK3 Pre-Seasoned Cast Iron Skillet, 17-inch

http://www.amazon.com/Lodge-L17SK3-Pre-Seasoned-Skillet-17-inch/dp/B00063RWVG

Based on these calculations, I'm planning to buy a second 15 inch skillet to stack on the first for my ceramic cooker, and I'm considering a stack of two 17 inch skillets on the floor of my indoor oven. It looks pricey, but not compared to swapping ovens. The thermal mass can only help for most applications, so they'd just live there. The stack of two buys me the liberty to use ice (shown here to be only slightly less efficient), which is safer indoors, and less likely to spatter and dampen my fire outdoors.

(I wish there was a term of art for forum responses of the form "I don't use sous vide and my food comes out fine!" Of course it does! Such responses don't give credit to commercial bakers who understand this problem far better than any amateur, and consider ample steam worth the trouble. As in, more steam than most of us have ever experienced, making bread for ourselves. If one can't make the comparison, one just doesn't know.)

I bake in my BGE, and I find that the airflow through the top vent effectively negates any impact of the steam. In plain English, any steam generated quickly goes up the top vent & doesn't hang around long enough to keep the crust flexible in the initial baking stages (to allow for max oven spring). The closed pot method works just fine in the ceramic cooker, though the bottom browns much faster/more thoroughly than the top. I solve this by flipping the loaf out of the pot about 10 minutes before the end of the cook, turning it face down to improve the color of the crust.

[Syzygies]

I bake in my BGE, and I find that the airflow through the top vent effectively negates any impact of the steam. In plain English, any steam generated quickly goes up the top vent & doesn't hang around long enough to keep the crust flexible in the initial baking stages (to allow for max oven spring).

I used to have #7 Kamado before my Komodo Kamado (http://www.komodokamado.com/). I thought they'd cook fairly similarly, but they don't. The K7 was basically steel wire and Portland cement; the KK is made from more advanced materials including substantial insulation. One can rest one's hand on the outside while a 600 F fire burns within. One can stop down the airflow nearly completely, and the KK will hold its temperature long enough for the steam to have its effect, if not to bake the bread. (One is required to mention at this point that one doesn't want to completely shut off oxygen to a hot fire, because of "flashback" when oxygen is reintroduced.)

Here's a more detailed comparison, reviewing the KK:

Komodo Kamado OTB 23-inch Charcoal Grill

http://bbq.about.com/od/charcoalgrillreviews/gr/Komodo-Kamado-Otb-23-Inch-Charcoal-Grill.htm

Bouchon explains nicely what "steam to have its effect" means. It's an effective way to moisten the crust. Tartine leaves bread in a combo cooker for half the bake, but it doesn't follow logically that one wants steam for half the bake; the Dutch oven approach is a workaround, and workarounds have different requirements. Bouchon's steam is largely at the beginning of the bake.

In any case, by far the best oven spring I've experienced so far involved boiling water and that one 15 inch skillet in my KK. A friend wants to build a bread oven after seeing that loaf. I've tried all the variations on combo cookers and Dutch ovens, and the effect isn't quite the same.

Your question does make me wonder how conventional wood-fired outdoor bread (pizza) ovens manage the necessity of steam. One coasts on stored past heat, like I do with my KK. Perhaps by baking enough bread at once, one is simulating the Dutch oven approach. I've certainly noticed this for low & slow barbecue cooks in a ceramic cooker (BGE, K7, KK): A very full cooker is more humid, and this has a beneficial effect.

In short, Keller et. al. are on to something. As you note, there are issues implementing this outside, or inside. That's a problem I want to solve.

Edited April 1, 2013 by Syzygies (log)

[HungryC]

A traditional bread oven bakes from retained heat--not the direct heat of a live-fire oven. You build a fire in a typical WFO, wait for the oven to reach the desired temp, then remove the fire, swab the hearth, load the bread, and close up the door. The bread bakes in falling temperatures--hot initially, slowly decreasing over time. I took a WFO class with Jeffery Hamelman--he added steam to a 3 meter hearth oven using a common garden sprayer--water was sprayed onto the walls of the oven just before the door was closed for the bake.

Are you shutting the upper and lower vents in your ceramic cooker and baking using retained heat? My big green egg will retain heat for quite some time, but it will not maintain 450-500 (my desired initial temp for a rustic hearth loaf) for the needed 45 minutes to cook a decent sized boule. Without a live fire, the temp will hover around 375 for an extended period. Too much heat is lost when the Egg is opened to insert the bread.

Edited April 1, 2013 by HungryC (log)

[Syzygies]

A traditional bread oven bakes from retained heat ... Are you shutting the upper and lower vents in your ceramic cooker and baking using retained heat? My big green egg will retain heat for quite some time, but it will not maintain 450-500 (my desired initial temp for a rustic hearth loaf) for the needed 45 minutes to cook a decent sized boule. Without a live fire, the temp will hover around 375 for an extended period. Too much heat is lost when the Egg is opened to insert the bread.

I have pretty much the opposite problem. If I get busy and find the KK at 650 F, dinner is going to be late, there's not much I can do quickly to cool it down. It has a lot of thermal mass inside the insulation, which radiates a lot of heat. And it's larger than a BGE. The Extra Large BGE is 205 lbs. The KK weighs 458 lbs, not counting the grills.

My ideal for many types of high temperature cooks (e.g. chicken) is to cook as much as possible from retained heat, once the fire is nearly spent. This is hard to do on a schedule, and bread is on a schedule: Once a loaf is ready to bake, one often has a narrow window for best results. Nearly shutting down the KK vents (not entirely, to avoid flashback) is almost as good as catching the fire on the wane.

The radiant heat can be uneven if the fire was uneven, and I have to remember to rotate the loaf.

[OliverB]

great updates, thanks!

[bethesdabakers]

On the other hand ...

My blog, The PArtisan Baker, is subtitled "Taking The Bollocks Our Of Baking". I'm thinking of changing this to "Bakers of the World Unite; You Have Nothing To Lose But Your Chains"

Mick

[Syzygies]

My blog, The PArtisan Baker, is subtitled "Taking The Bollocks Our Of Baking". I'm thinking of changing this to "Bakers of the World Unite; You Have Nothing To Lose But Your Chains"

I adore a spirited debate, so I raced over to see what you had to say. Not easily finding my bearings, I then applied a site-specific Google search which returned the following three links:

site:thepartisanbaker.com steam

http://thepartisanbaker.com/2012/03/30/boston-brown-bread/

http://thepartisanbaker.com/starters/

http://thepartisanbaker.com/2010/03/12/dalek-bread/

If you have an opinion on adequate steam for baking single loaves of bread in a home oven, I couldn't find it. You surely have much more experience baking that I do; I'd love to read what you have to say about steam on your blog, when you write it.

My approach here (and I presume of many of us) is to figure out how to make a technique practical for my circumstances, master it to a degree any proponent would view as a fair test, and then decide for myself if the technique is worth the trouble. This thread is such an exploration, and a poster child for why I love eGullet. Meanwhile, one humors many assertions not based on comparisons, that one is satisfied with one's results without exploring said technique. Fine.

Meanwhile, I'm reminded of a neighboring thread, on how one can't blindly trust Google restaurant ratings. One has to consider the context of each such rating. Huh. There are many sources competing for attention in the bread baking arena, and strong evolutionary pressure for each entrant to brand themselves into one corner of the ongoing debate. "Five minutes" or "no knead" bread? Tartine Bread and Flour Water Salt Yeast are moderates near this corner (relying on bakery fame rather than point of view for sales)

http://www.amazon.com/Tartine-Bread-Chad-Robertson/dp/0811870413

http://www.amazon.com/Flour-Water-Salt-Yeast-Fundamentals/dp/160774273X

and they both advocate a truly modest amount of folding of the dough for superior results. Could any author that branded themselves out of this option ever admit that this actually makes a difference? I observe that it does. Understanding bread advice is like understanding restaurant reviews.

So my fear is that calling oneself a partisan backs one into a corner. The truth is often somewhere in the middle. I'm glad that I learned something about the physics, and boiling off a few cups of water with 30 lbs of cast iron isn't that challenging. We all have baggage; mine is that my parent's generation believed that the thin copper film on Revere Ware pans actually did something. There are matters of scale in cooking, and Bouchon Bakery is addressing this matter of scale with their rocks and chains. And of course setting up the potential for backlash. Stacking a few giant cast iron skillets is boring by comparison.

[Syzygies]

Here's a great link on the physics:

Counting Calories

http://www.mansfieldct.org/schools/mms/staff/hand/countingcalories.htm

The key numbers: It takes 80 calories to thaw a gram of ice, 100 calories to bring that gram to the boiling point, and a whopping 540 calories to then turn that gram of water to steam.

Different sites discuss the relative heat stored by different substances. Cast iron holds about 13% as much heat energy as water, degree by degree. Stones hold about 20% as much heat energy as water.

So if one runs the numbers, a 15 lb cast iron skillet at 500 F will boil off around 250 ml of water.

So, comparing three setups

• Cast Iron Combo Cooker (Tartine Bread, or similar enclosure)
• Heavy (11.4 lb) skillet for steam in Komodo Kamado ceramic charcoal cooker
• Heavy (13.4 lb) skillet for steam in conventional indoor oven

I can add a few observations:

Placing a skillet on the floor of an oven, or right on the fire, the skillet gets hotter than the nominal oven temperature, and the skillet does reheat like a pot on a flame, not a stew surrounded by air on an oven rack. So one gets a bit more steam right away, and later, than I've suggested. Nevertheless, I plan to double up my skillets.

A Dutch oven or cast iron combo cooker enclosure contributes not only enclosed steam, but radiant heat, which changes how the crust cooks. I see significant radiant heat in my first two setups, but not in my conventional oven, and it's obvious in the crust. A matter of taste; the radiant heat crust is more dramatic, yet my wife prefers the plainer crust as a supporting player, just good food not about the bread.

Have others who have given both Tartine Bread (or other enclosure advocates) and Bouchon Bakery fair trials also seen this difference? Can one compensate with higher heat, or a stone just above the bread?

(Over a charcoal fire in a ceramic cooker, hotter air is never the same as more radiant heat from cooker walls...)

Edited April 6, 2013 by Syzygies (log)

[HungryC]

Enclosed pot breads require high hydration....you can't just put any old bread into an enclosed vessel and achieve stellar results. A typical American slicing loaf enriched w butter, milk, and eggs will not benefit from enclosed cooking. This same bread doesn't benefit from in oven steam, either. It's a matter of matching the technique to the dough and the desired result...one method is not ultimately better than another, they just deliver different textures.

[Syzygies]

you can't just put any old bread into an enclosed vessel and achieve stellar results.

With identical recipes (78% hydration, 60% freshly ground, sieved whole grain, hybrid sourdough, from a spreadsheet not a book) I see a dramatic difference from radiant heat, separate from the effects of steam. An enclosure facilitates radiant heat and steam.

My question was how others make up for less radiant heat, following Bouchon Bakery's advice.

[bethesdabakers]

So you're a mathematician. Of two earlier mathematician/bakers one created a dozen made up of thirteen and the other a system of percentages totalling more than one hundred. Third time lucky ....

I hope that by the end of this thread you have developed a formula for rating ovens by the number of links of chain required to produce the optimum amount of steam. Have to have a standard metal, bar thickness, link diameter, etc - a factoring for altitude? Links by oven litre? Maybe the units could be called bagels ... You can do it!

The reason you can't come up with anything on steam linked to thepartisanbaker is I don't use steam (apart from naturally occuring)so I don't write about it. By the way, the use of the word partisan is to do with the total debasement of the word artisan in relation to bread and bakers not to taking a narrow and fixed position.

Don't worry I shall be posting Mick's No Nonsense Method soon so you can have a pop back at me.

Best wishes

Mick

[Syzygies]

On topic, there's one possible advantage to rocks and chains, over stacking several 13 lb cast iron skillets: Vaporizing all the spatter.

[dcarch]

Radiant heat is also dependent on the color/ reflectivity of the vessel, (black body radiation) and the color of the contain.

dcarch

[bethesdabakers]

As you say "on topic".

I've been waiting to see all these examples of how steam (generated by rocks, chains, whatever) improves bread.

Nothing forthcoming.

So here's a question. Which four of these loaves was baked with steam? (The steam in this case generated by a plant mister - 3 squirts each top left and right against the walls of the oven, same middle and bottom.)

[Syzygies]

I'm guessing middle two, top row, and right two, bottom row, but that's based on how the center slash filled in. I agree they're all close.

I'm thrilled that you took on this experiment. I go through stretches where I make a loaf a day, trying to sort out all the variables. Talk is cheap; I believe most in comparisons and experiments.

Bouchon Bakery calls for 350 grams of water to turn immediately to steam. Can you estimate (with a scale before and after practice squirts) how many grams of water you used? I made a game out of trying to get as much water as I could out of my plant mister in twelve squirts, and the most I could manage was 15 grams. In other words, Bouchon Bakery is calling for over 20 times more steam than I could hope for by your method. Your plant mister may be more effective than mine, but I'd be very surprised if 12 squirts yielded 350 grams.

I presume that they advocate a large mass of chains and rocks, despite the obvious potential for amusement at their expense, because they felt that anything short of such measures would be insufficient. Likewise, commercial bread ovens are capable of producing lots of steam, and commercial bakers rely on this feature. I need an explanation for why this is, before I can dismiss the benefits of steam.

My own experience agrees with your picture: I had a hard time telling the benefits of a few squirts of a plant mister. One could draw two possible conclusions from this: Either steam doesn't help much, or I wasn't using enough steam. I drew the second conclusion.

Rock is a bit more efficient, but my calculations indicate that it takes over 20 lbs of cast iron to turn 350 grams of warm water to steam. My experience with a somewhat lighter skillet backs this up. One difference that I notice is that the bread smells "right" baking in an oven with lots of steam. Of course this is subjective.

A massive skillet (or two stacked) is easier than rocks and chains, but I've had to deal with potential rust. Reseasoning helps. Another option for mass is a baking steel, which I have on order: http://bakingsteel.com/shop/the-big/ These have other uses, and one could protect them from rust with a steel tray on top.

[Broken English]

Has anyone ever tried running a small metal tube into the oven via the oven door and injecting continuous steam for the first few minutes?

I don't think that is necessary. In my Dad's baking oven the steam hit goes for ten seconds or so once you press the steam button, the moisture lasts long enough for the bread to kick up and become lighter. Any further moisture seems redundant to me.

[Syzygies]

I admire loaves with crusts displaying a volcanic "back side of Alicudi" violence, like the preceding quiz picture. I'm hooked on the taste and keeping qualities of levain rather than yeast, and as much freshly ground whole grain flour as practical. I remember the 60's, when whole grain bread was ghastly, and clearly not the same food the French were thinking of. Here, the challenge is not to produce a flying saucer. Sieve out as much bran as possible, which cuts through gluten, and mix entirely by hand, with many folds during the first part of the bulk rise as taught by Tartine Bakery. The loaves should be truly springy when formed, or something is wrong.

250 grams of steam at the onset turns the loaf into a bulging water balloon, with a taut skin. Some might be disappointed that I didn't put a deeper char into the crust, or achieve more volcanic violence. That might be for white flour; with my ingredients I'm happy to no longer be making flying saucers.