One of the first pieces of advice that I was given when I started proudly posting my absurdly exploded breads was that “you need steam”, and I had not a clue of how to make it happen.
You might have also heard about “adding steam” if you’ve been trying to take your home baking to the next level, to obtain a more “professional” finish: deeper colour, sophisticated blisters, and a shiny appearance that screams: EAT ME! I AM TASTY!
But if you’re like me, you’ll be also wondering: WHY? How does that work? 🤨🤔
I was frustrated for the longest time because I did not understand how any of this worked, and the methods proposed did not seem to have any effect at all. It took a while for things to “click” in my brain and make sense. This is my attempt to share what I’ve learned!
In this post, I’ll explain…
- how steam helps to make better breads
- how to create steam in a domestic oven
- why you should feel very free to entirely ignore this for now
- another method to create steam, with a casserole
- and how the bakers of old achieved this too, but without resorting to graphs and talk of SCIENCE
Hopefully you’ll get something useful out of this!
Excuse me, how does steam change things?
When steam (or moisture in the air, by any other name) is present in an oven during the first minutes of baking, interesting CHEMICAL PROCESSES 🧪⚗️ will take place.
- an increase in elasticity and delayed crust formation: the higher moisture level allows the surface to remain elastic for a longer time, so the bread can keep expanding before the crust forms and sets. The crust might also be thinner (and make crackly sounds when it cools down later).
- gelatinised surface: at 82ºC/180°F, the starches in the barely formed crust start absorbing moisture, creating blisters that eventually burst and release a gel that creates that glossy professional look that we’re after.
- delayed caramelisation and Maillard reaction: at 135ºC/275ºF the sugars in the crust start caramelising. Later, between 150ºC and 205ºC (302°F – 401°F), the Maillard reaction takes place, with sugars and amino acids reacting with each other and caramelising even more. If this happens too early in the process of baking because the surface reaches these temperatures already, the inside of the loaf might not have finished cooking or expanding before the surface is formed and “toasted”.
Steam in the oven slows down the temperature increase in the surface of the dough, thus delaying crust formation, caramelisation and Maillard reaction. The results? Plump, open loaves with an intense and shiny colour!
Or if you are a visual person, look at all that extra time for stretching that steam gives us:
Sole’s SCIENTIFIC THOUGHT PROCESS to create steam in a domestic oven
Professional ovens these days have a button that says “STEAM”. They press it and ta-da! Steam gets flushed into the oven. Magic!
Sadly, not a very practical piece of knowledge for us, home bakers.
While there are home ovens that have a “steam feature”, unless you’ve very deliberately refitted your kitchen, I doubt you’ll have one of those.
So assuming you have a humble domestic oven, like we do, let me walk you through the very SCIENTIFIC thought process I followed to create steam when baking:
We want: to highly increase the amount of moisture in the oven during the first minutes of baking.
We also know: that the loaf will not instantly start baking right after placed in the oven, because the air does not conduct heat as quickly as direct contact would.
So we have a small window of time in which we can generate and keep a lot of steam really quickly, before the crust starts drying out and setting.
Thus the question is: what can create or retain the most steam in the shortest amount of time?
|Most steam||Least or slowest steam|
|Very hot elements getting in contact with hot water.||Spraying the oven with water: by the time you close the door, possibly half of the water has already evaporated. It does not create sufficient moisture. And it can also possibly damage the lightbulb and other electrical component if you direct your stream towards the wrong place.|
|Not opening the door after placing water / steamy things on it.||Placing ice cubes in a tray: they take so long to start melting, by the time they start evaporating it’s possible your crust has already formed.|
|Fan off (the fan not only moves air around, it also takes some air and its moisture out… at least in our oven).|
And thus, my solution
What you’ll need:
- an oven which lets you switch the fan off
- an oven thermometer
- a metal tray or shallow pan to pour hot water in
- a jug to pour hot water into the tray (like a Pyrex jug)
- some way of heating water outside of the oven (we use a Quooker tap, but a kettle or a pot on the hob are also valid options)
- oven gloves or similar protective element
Pre-heat the oven to ~220ºC, using either fan or not, it does not matter. Just make it hot, and use a thermometer to make sure it really is that hot. Our oven invariably lies and beeps about 30 minutes before it actually reaches that temperature, as evidenced by the thermometer we have on a tray.
Place a tray or shallow pan underneath the rack where the loaf will go. This tray is in from the time we turn the oven on, so by the time it is HOT, the tray is hot too.
If you’re using the fan, turn it off before placing the loaf in the oven, and set the oven to lower heat only—this will help us in delaying crust formation! Wait for a bit until the lower heat element is on, if need be.
Place the loaf on the middle rack.
Then pour about 100-200 ml of hot water on the hot tray below. Use gloves! Don’t burn your hands with splashes of water!
Finally close the door! And wait.
After about 5 minutes, you might see the water in the hot tray starts to boil and evaporate in abundance… which gives steam! You might even see swirls of steam around the oven, which is a very good sign that the process is working.
During the next 15 minutes, the loaf will start expanding as the dough gets warm and the yeasts do their final fermentation before dying. Since there’s steam in the atmosphere, the crust can go on expanding as described above. Also, given the top heating element (usually a grill) is off, and the lower side of the loaf is protected from direct heat because there’s a tray with water underneath, the temperature should be increasing quite gently, so this gives us a smooth warm up.
At some point you’ll start seeing the upper side of the loaf get some colour, and it might also mostly have stopped expanding. This is the time to start baking “as usual”: you can either switch the oven to both upper and lower heating elements on, or turn the fan heating on.
If you turn the fan on, be aware that because it circulates the heat more, the temperature “raises” by about 20ºC. So you might want to lower the thermostat by about those 20ºC now, to avoid things burning. You can also remove the tray underneath if you want, although I often don’t (and haven’t seen a considerable difference).
After about 20 minutes, you might want to turn the loaf around so it gets uniformly baked.
Take the loaf out once the crust is golden enough to your liking. If you use a tin, bear in mind that the tin “protects” the loaf sides, so it might need an extra 5-10 minutes (even if the uncovered area looks brown enough to you).
In other words, it’s important to keep an eye on your loaf and see how it’s doing.
This is a lot of faff. What happens if do not add steam?
It’ll just be less shiny, and it might also happen that your bread gets deformed in funny ways, but it’ll be equally tasty. I’ve made plenty of funny looking breads!
Sometimes the pressure of the internal expansion causes the surface to crack open in unexpected ways, not along the scoring line, since it lost its elastic abilities as it baked. Other times the loaf can grow a “hump” if the heat isn’t very well distributed and the shaping wasn’t well done and it could not cope with the tension, etc. It truly does not matter at the beginning; it’s better to focus on the taste 🙂
I decided to ignore “adding steam” for the longest time, and focused on enjoying the rest of the process, and I think it’s the best thing you could do too if this sounds too tedious.
Stick to the ~45 minutes of baking with a half-way turn around, and it’ll be fine.
For comparison, loaves baked without and with steam:
Other method: with a casserole or Dutch oven
This is another fabulous method that gives very nice results with equipment you might already have at home.
In this method, instead of adding moisture, we allow the loaf to “moisturise” itself:
- Place a really thick iron casserole or pot with lid in the oven while it warms up
- then take it out and place the loaf in it
- replace the lid
- put them back into the oven, cooking with the lid on for the first 15-20 minutes (some recipes advise cooking like this for the whole 45 minutes though).
This is all thanks to two facts:
- the metal in the pot is a great retainer of energy i.e. HEAT. When you place the loaf in direct contact with the metal, it gets super hot really quickly, and starts baking, which releases moisture from the dough as it cooks and evaporates, but…
- the moisture is retained inside the pot, thanks to the lid which is also VERY hot. So the moisture keeps circulating (not condensing on the top) and this keeps the crust from drying, while the loaf plumps up!
I’ve used this method many times and I love it, but it has some drawbacks:
- you can’t use it if your loaf won’t fit in the pot. For example if you want to bake batons but your casserole is round. Or if you want to bake on a tin; in this case you cannot use this method.
- you have to handle a heavy and very hot pot in and out of the oven. This can at the minimum scare people but it can also be a physical impediment. I’m certainly a bit intimidated by it!
- you can burn yourself when placing the loaf in the hot pot (as happened to Devvers), although if you use baking paper it’s easier to just ‘drop’ the loaf without burning yourself.
Or the traditional method: the “sacrificial” loaf
I have a couple of books on traditional and regional baking which are really lovely to read.
In particular I enjoy reading about the methods that artisan bakers of old intuitively developed to achieve the results we seek, without all the chemical dissertations that I subjected you to above.
One of these methods is the use of a “sacrificial” loaf that is baked first. This helps the bakers assess if the oven is hot enough to bake the rest of loaves of the day, and it also helps to fill the oven with steam, by releasing its own moisture when baked.
A good way to release the maximum amount of moisture from a piece of dough is to maximise the amount of surface area it has. Which you can do by shaping it like French fougasses, which are scored multiple times to increase the ratio of crumb surface to crust.
Of course, like all proper stories of old, they also slightly contradict each other: some places say that actually you want to cook the fougasses with the oven door open so that the steam does not accumulate because otherwise you don’t get the soft crumb you want. What’s true? I don’t know! I don’t know any French baker of old, so if you do, please illuminate me. But do know that I will take it with une pincée de sel 😂
Interestingly, it seems that artisan ovens also frequently have a low ceiling, which helps to concentrate the steam and keep it close to the loaves as they bake.
I’m not sure this method is very useful in a domestic oven because they’re so shallow that each time you open the door most of the steam is released, while proper old fashioned wood-fired ovens might be deep enough that the baker needs to use a long implement to place loaves in. And this long ‘corridor’ helps keep the heat inside the “core”.
Anyway, if you are curious, I’d recommend Pan de pueblo by Ibán Yarza (in Spanish) and French Regional Breads by Mouette Barboff.
Also, this explainer article is a good summary of the chemistry bits: Why Does Steam Make Bread Light and Crusty?
I made the drawings with Excalidraw. In absence of a whiteboard, it is the best next thing!