LETTING OFF SOME STEAM
I like big bread, and I'm blaming Peter Reinhart. I remember browsing the cooking section of the local bookstore and seeing the cover of his book, The Bread Baker's Apprentice, with the cover photo of a woman holding a huge miche of bread.
The Bread Baker’s Apprentice by Peter Reinhart. Photo by Ron Manville.
My immediate thought was: I want to make that! If bread is the staff of life, there's a lot of life in that loaf. When you walk in the door with 5 lbs. of bread, it's like bringing in a 20 lb. roast turkey or a standing rib roast; it sets off a primal feeling that nobody is going hungry today. Especially if you bring 2 lbs. of butter.
So I read Peter Reinhart, Ken Forkish (who has a great section on The 3-Kilo Boule in Flour Water Salt Yeast), Jeffery Hamelman, Chad Robertson and more. I found a lot of bread blogs; I really like Girl Meets Rye (have not seen anything new in a long time) and The Perfect Loaf. I made the pilgrimage to 8 Rue du Cherche-Midi in Paris and was happy I could fit a few miches in my carry-on bag. And I practiced. A lot. And made so much not-so-great bread I worried the local birds would not be able to fly south for the winter. But, I did get better, and the birds did fly away.
This gets pretty involved (and long). If you want to skip the science and math, click here to go to THE CULMINATION.
A steamy oven is propitious to bread, particularly the crust. For this reason some writers advocate that a tin of water be put on the lower shelf while the bread is baking. I have not found the system particularly helpful and have abandoned it. To be efficacious, the steam should be at very high pressure, injected into the oven in a fierce burst during the first few minutes of baking. Once the crust is formed the steam is withdrawn and the bread finishes baking in dry heat. In an ordinary domestic oven these conditions cannot be fulfilled, so the crust on home-made loaves is rarely as thin and crackly as it is on bread from an old-fashioned family bakery. Elizabeth David, English Bread and Yeast Cookery
Since Ms. David wrote her book, we've learned that you can get thin and crackly crust in an ordinary domestic oven if you bake the bread inside a Dutch oven or cloche. But you would need a $560 Le Creuset 13-1/4 quart model to make the miche in the picture. The $560, plus the thought of wrestling around 22 lbs. of hot cast iron, and getting 5-6 pounds of dough in and out (plus the fact that if I bought another double digit pound piece of enameled cast iron with a triple digit price, shelves could collapse and there could be a revolt), was one of the inspirations for making the BakePlate, but that's another story for another time. You don't need a 13-1/4 quart Le Creuset, and you don't need a BakePlate to make that miche. What you need is steam. Steam that condenses on the bread, letting that miche rise and shine.
How do you get steam into a home oven? That question that will bring you the trifecta of folklore, hocus pocus and bad math you find in any craft practiced for thousands of years. You read about cast iron pans of water, spraying the sides of the oven, lava rocks, ice cubes and frozen wet dish towels and try them all. You try combinations. You buy an atomizing spray bottle from the art supply store and succeeded in pasting a miche of bread onto a BakePlate. You find, on a 5-6 lbs. of dough, none of it is very efficacious. I'll spare you another 996 words.
These things don't work.
And you learn why the Dutch oven or cloche method is so popular - it does actually work. So, hoping to replicate a Dutch oven, you put a pre-heated 16 qt. stainless steel mixing bowl over the dough the first 15 minutes of baking, and give the results a C-. But you're still not buying the $560 Le Creuset 13-1/4 quart Dutch oven.
One thing everyone agrees on is that steam must be used in the very beginning of the baking. Once the bread starts to brown, steaming should be stopped. In commercial ovens, the vents are closed so the steam that is shot into the oven during the first minute doesn't just run out the exhaust vent. Home ovens don't have closable vents; mine exhausts over the stove top. Don't think you can create your own closable vent by stuffing towels across the exhaust. The exhaust vent on my oven apparently runs underneath the electronics on top of the stove, and is designed to let heat and moisture out of the oven. If you stuff towels across the exhaust, the moisture gets up into the electronics. The digital displays start blinking and beeping, like there was a power outage. There is condensation on the inside of the digital display. I unplugged the stove and ran a hair dryer across the electronics for a while and everything, except for a few water spots, went back to normal. So don't do that.
I know that baking this 6 lb. piece of dough takes longer than a normal 1.5 lb. miche; the oven spring alone can take over 10 minutes. Since my oven vents are not blocked, as soon as I start putting steam into the oven it's going to start going out the vents. I also know from my previous experience with ice cubes, cast iron, lava rocks and sprayers that turning 8 ounces of water into steam has no discernible effect on 5-6 lbs. of dough. I need more steam.
How much steam? Nobody can really tell you. Since steam generators range in size from the small one that de-wrinkles one of my daughter's umpteen bridesmaid dresses to the big one that pushes an aircraft carrier across the ocean, the normally helpful Jeffery Hamelman is not, when he advises in Bread, "About 8 seconds of total steam should suffice." Which is more, 8 seconds of steam or 8 seconds of cast iron? For about 8 seconds, I thought I finally found the answer on page 93 of Volume II in the Fourth Edition of Baking Science and Technology by E.J. Pyle and L.A. Gorton, a pair of books so expensive you'll wonder if they come packed in a Le Creuset 13-1/4 quart Dutch oven:
Typical steam injection calls for an additional 9.25 cu ft per lb of dough.
But then the following paragraph says:
...the best steaming results are obtained by injecting low pressure (2-5 psi) saturated steam at a rate of 200 to 500 ft per minute over the baking product during the first minute of baking.
If typical commercial hearth ovens range in size from 100 to 500 lb. of dough capacity, that would mean they are adding 1-2 cubic feet of steam per pound of dough. So the range, in two paragraphs in the same book, is 1-9.25 cubic feet per pound of dough.
The best advice came from the section on steaming in the on-line Variety Hearth Breads course from AIB International. Bottom line, there are too many combinations of ovens, steamers and dough mixes for anyone to tell you how much steam to use. You'll know it when you see it, the bread will look wet and there may be condensation on the oven window.
My miche recipe is 6 lbs. of dough. If I need somewhere between 1 and 9.25 cubic feet of steam for each pound of dough, that's 6-55.2 cubic feet of steam.
A quick lesson in steam:
In the U.S., unless you're Jeffrey Hamelman, steam is measured pounds or cubic feet. What's a cubic foot of steam? If you look at a steam table, the kind that shows the properties of steam at various pressures, not the kind that keeps food hot, you'll see:
1 BTU is the heat required to raise the temperature of 1 lb. of water 1°F (up to boiling).
At 0 PSIG, which is what we have in our oven, 1 pound of steam is 26.80 cubic feet. And 1 pound of steam weighs the same as 1 pound of cast iron, 16 ounces. How do we make 1 pound of steam? We take 16 ounces of 70°F water and heat it to 212°F, or boiling. That takes 142 BTUs. Then we add another 970.3 BTUs of heat to the 16 ounces of boiling water to vaporize it into steam. 1,112 BTUs turns 1 lb. of 70°F water into 1 lb. of steam.
If I need 6 to 55.2 cubic feet of steam, at 26.80 cubic feet of steam per pound I need 0.22 to 2.06 pounds of steam, which is 3.52 to 32.96 ounces. Let's round that to 4-32 ounces. 8 ounces isn't enough, let's move to the other end, 32 ounces. It boils down to this: if we want 32 ounces, 2 pounds, of steam we need 2 pounds of 70°F water and 2,224 BTUs, or 2 pounds of boiling water and 1,940 BTUs.
I'm going to work with the 1,940 BTUs because I know I can boil a quart of water. Your stove top burner, once it brings water to a boil, can make about 12 ounces of steam in 10 minutes. I guess you could use multiple stove top burners and pipe into the oven, but that sounds crazier than blocking the exhaust vents. Your oven is busy baking bread and doesn't have spare BTUs to make steam, unless you accumulate them and store them before you start baking. To make this simpler, the heat the oven is producing, opening and closing the oven door, etc. is going to be ignored.
Since we're making steam, we want temperatures hotter than boiling water (212°F). The maximum temperature of the oven is 550°F, so we have the 338°F between boiling water and maximum oven temperature to work with. When you divide the 1,940 BTUs required by the 338°F available you find you need a heat capacity of 5.74 BTU/°F.
How much heat a material will hold is its specific heat capacity, and is measured in BTU/lb/°F. Water has a specific heat capacity of 1, porcelain ceramic has a specific heat capacity of 0.20, so 1 BTU will raise the temperature of 1 lb. of water 1°F, and 0.20 BTU will raise the temperature of 1 lb. of porcelain ceramic 1°F. 1 lb. of water has a heat capacity of 1.0 BTU/°F, 5 lbs. of porcelain ceramic have a heat capacity of 1.0 BTU/°F.
We need a heat capacity of 5.74 BTU/°F. That's either 48 lbs. of cast iron, 52 lbs of steel, 29 pounds of porcelain ceramic, 25 lbs. of cast aluminum, 22 pounds of firebrick, or some combination of those materials. For the 3 of you checking my math I'm using specific heat capacity of, respectively, 0.12, 0.11, 0.20, .23, and .26 BTU/°F/lb.. I know from working on the BakePlate that the typical minimum weight capacity of an oven shelf is 25 lbs., so I'll subtract the 2 pounds of water and use 23 lbs. as the maximum weight for BTU storage. I'm about to throw in the frozen dish towel when I see something that brings back a fond memory of a late friend telling me I was the dumbest smart guy she knew.
There are 3 racks in the oven. One is holding the baking plate/stone/steel, one is going to hold the BTU storage. The third one doesn't have to stand between the kitchen cabinet and the refrigerator, it could go back into the oven and hold more BTU storage. Take 1 pound of water from each and we can have 2 racks of BTU storage at 24 lbs. each.
THE PERSPIRATION and a few burns
Baking sheets, ceramic tile, and aluminum sizzle plates were dropped on the porch. Cast iron skillets, platters and pans started arriving. 50 pound bags of flour were the norm; neighbors, family, friends and co-workers were consuming the test results. I tried all this, and more:
The most expensive thing I tried was an 8.5”X8.5”X1.25” piece of aluminum plate in a Lodge 15” skillet on a Vollrath 10 gauge half sheet, and that’s before the boiling water splashed off the flat plate onto the door glass and shattered it (see below). Water gets under the flat plate and pops, lifting and dropping the plate. It sounds like there’s a gun battle going on in the oven. The least expensive thing I tried was 3 pieces of ceramic floor tile, broken into pieces, in an Ozark Trail 15” skillet. Ceramic holds a lot of heat, but the heat moves through the material very slowly. It’s like lava rock, you can’t get the water where the heat is. And finally.
2 pounds of steam on 6 pounds of dough worked well; it made the thin, crisp crust I wanted. My suspicion is the volume of steam is related more to the volume of the oven than the weight of dough that’s in the oven, but that's another experiment. I wound up a little over my target weights, with 26 lbs. on one rack and 16 lbs. on another, but it seems to be holding up fine. Here's how to do it:
WARNING WARNING WARNING WARNING WARNING WARNING WARNING
This process involves lifting objects over 15 lbs., pouring boiling water on 550° F materials, and making large amounts of 212° steam. While working on this process, I have broken the oven more than once and hurt myself more than once. You can, too! I don't break the oven or hurt myself anymore, yet. If you choose to try this, at your own risk, I implore you to wear personal protective equipment, keep other people and pets away, and be careful. If something breaks or someone gets hurt, don't you, or your lawyer, come crying to me.
Personal Protective Equipment
Rapicca Heat Resistant BBQ Gloves, 17 inch 932°F
I love these gloves. No, you're not doing BBQ, but you are working with steam. Any uncoated fiber glove is going to get wet and be useless. Wear long sleeves and these. I got rid of all my other oven gloves, these are much more useful. Flip a turkey, re-arrange racks of ribs, pull custards out of water baths, just reach in and do it them wash them off in the sink. They're going to be stiff and smell of plastic when you first get them, that will go away in a few days. One warning: you can’t pick up something that’s 932°F, that must be the temperature the neoprene melts. I don’t pick up anything over 375°F. If I pick up anything hotter that that I feel it in about 2 seconds and need to put it down. If the distance from the tips of your fingers to the inside of your elbow is less than 17”, you want the 14’ gloves.
Fogtech DX Instant Anti-Fog
When you’re pouring boiling water into the oven, steam is billowing out onto your face. If you wear glasses, they are going to fog up, and you won’t be able to see while holding the pitcher of boiling water. You can get these from REI or Amazon. Update: Now that we're wearing masks and constantly fogging our glasses, there are anti-fog products available everywhere from Walgreens to Warby Parker.
Borosilicate Glass 4 Cup Gravy Strainer
HIC or Catamount, they are both very similar but I prefer the blue writing on the Catamount. The Catamount is also available in white, black and red. It has to be borosilicate glass, you’re pouring boiling water into it.
5/8” ID 11/16” OD Extreme Temperature Teflon PTFE Tubing, 2’ long
You can order this online from McMaster-Carr. 2 feet is the minimum order, you need 1 foot. I cut a ¼” slit in one end, stuck it in a pan of boiling water (while wearing my Rapicca gloves), slid it over the spout of the gravy strainer, then trimmed it off. So it looks like this:
This is what you use to pour the boiling water into the pans.
They come in boxes of 50, you’ll need 1 box.
A bargain for this much cast iron. The bottom is 10 lbs., the top is 8 pounds. You’ll need 2 sets, and will qualify for free shipping.
Tea Kettle, 2 quart minimum.
15” X 21” Aluminum Sheet Pan
It could be 5/8 size, ¾ size or just big. Its purpose is to protect the glass in your oven door. If you think you don’t need this,
this is what it looks like when you spill boiling water on a 550°F oven door. The replacement glass lists for over $200.00 but you can find it online for $150.00.
1. Place the ceramic briquettes on their sides in three rows of eight in each of the cast iron pans.
- Place the two pans of briquettes in the oven with the rack at the lowest position.
- Place the next rack 2 slots above the bottom rack and center one of the pan tops on the rack.
4. Place the third rack in the slot above the rack with the pan top and put your baking stone or BakePlate on the rack. And we're ready to go.
Start with your favorite bread recipe. Try this one if you're just starting out. Increase the flour content to 1500 grams, and adjust everything else according the recipe's Baker's Percentages. You can use a linen lined mixing bowl at least 12" in diameter for a proofing basket (you could also just make a normal sized loaf). The schedule below is based on your dough going into the oven at 10:00AM
8:00AM - Preheat the oven at 550°F for 2 hours. Your oven is going to tell you it’s ready a lot sooner than that, but it is monitoring the air temperature. It will take 2 hours for the pans, briquettes and baking stone to reach 550°F.
8:30AM - Take the miche out of the refrigerator and place it on the counter, leaving it covered.
9:50AM - Fill the tea kettle and place it on a burner set to high.
9:55AM - Do the final prep on the miche, when the water is boiling in the tea kettle, slash the top.
10:00AM - Turn the oven temperature down to 460°F. Put on the gloves and pour 8 oz. of boiling water into the gravy strainer. Open the oven, place the sheet pan over the oven door glass and pour 8 oz. of water over the pan top. This pre-steams the oven before you set the miche on the stone and also cools off the stone. 550°F is too hot to bake on. If you’re using a BakePlate you can just pour the 8 oz. of boiling water onto the baking surface. Place the miche on the baking surface and close the oven door, leaving the sheet pan over the oven door glass. Pour 12 oz. of boiling water into the gravy strainer, open the oven door and pour it into one of the briquette filled pans. Close the oven door.
10:02AM - Pour another 12 oz. of boiling water into the gravy strainer, open the oven door and pour it into the other briquette filled pan, then close the oven door. Here is another view:
10:03AM - Open the oven door and look at your miche. It should be wet. If it’s not, pour another 8 oz. of boiling water into the gravy strainer and pour half into each of the 2 briquette filled pans. Remove the sheet pan, close the oven door and turn off the burner under the tea kettle.
10:15AM -Wearing the gloves, remove the 2 briquette filled pans from the bottom rack (making steam takes a lot of the heat out so you can pick them up) and place them on top of the stove or on hot pads, remove the miche on a peel, rotate it 180° and place it back directly on the baking surface (when I first put the miche in the oven it’s on a piece of baking parchment, I remove the parchment when I take it out to rotate). Turn the oven temperature down to 420°F.
10:25AM – Rotate the miche 90°(1/4 turn).
10:35AM – Rotate the miche 180°(1/2 turn). Check if the miche is done.
10:45AM – Check if the miche is done.
You can alter the crust on future bakes. More steam makes a thicker crust.