Steam in a Domestic oven, why & how?
Home baking or ‘amateur’ baking – in the true sense of the word – has it’s own idiosyncrasies in a domestic kitchen and some require a little more thought or improvisation.
How to generate steam in a domestic oven is one of those things I get asked often. There are lots of ideas advanced on how to best generate steam in a domestic oven for baking bread. Some seem to be easily achieved with good results, others are terrible and really don’t do the job as they are based on inaccurate understanding of the role and effect of steam on bread dough. However, before I pen a few ideas how to make steam at home it would be good to understand just exactly what steam in the oven does and how it improves bread quality.
Firstly, it has several functions:
- produces crust shine
- produces crust brittleness
- improves crust bloom
- improves bread symmetry during ovenspring
All of the above improve the overall bread quality from mouth feel to appearance and flavour. To be brief this is how those characteristics are achieved.
If adequate amounts of steam is generated in the oven while the cold dough enters the oven, steam condenses on the dough surface. This condensation gelatinises on the dough surface. The key here is adequate amounts of steam and cold dough. This means the steam must be applied in the very initial stage of baking. It’s no good after the surface of the dough is hot and dry. This means the quicker you get the steam in, on loading your dough into the oven, the better!
Assuming you’ve successfully done both – generated adequate steam when the dough first enters the oven – the condensation I mention will ‘scald’ the surface of the dough producing a gelatinised surface which will produce a shine. This shine is the by-product of scalding starch which produces translucency. Its a bit like cooking or bringing to the boil a starch and water slurry. You will notice as the starch thickens it becomes translucent and glossy as its surface reflects light. But it also allows light to pass through. This is responsible for the shine on the bread surface.
Starch in a gelatinised state on the surface of the dough also becomes brittle if it’s baked beyond the threshold where enough of the moisture is driven out. This is a critical point. If it’s not baked sufficiently it will be leathery and tough.
Of course during cooling and storage moisture migrates from the bread crumb to the crust. This will eventually soften the crust but if baked properly – beyond the threshold referred to it will remain pleasant to eat not only while it’s crisp and brittle but also after it has softened. From a sensory perspective the crust will continue to be more palatable and ‘mellow’ even after it has softened due to moisture migration. This is not the case if the bread is not baked beyond that threshold.
This same shine will allow the natural bloom to be seen. Bloom can be described as the depth of colour and brightness of the crust when properly caramelised during baking. Bloom is a by-product of a balanced formula and a properly fermented dough. But if the dough doesn’t have sufficient steam at the right time in the oven much of the bloom will remain unseen.
As inferred in other posts, bread making is a series of interrelated biochemical processes and physical steps that influence the dough from start to finish. This is why there is usually more than one cause for any bread fault. The symmetry of bread is mainly influenced by final moulding but its also affected by other processes and steam during initial baking is one of those. Assuming all the earlier steps have been executed properly the dough will expand greatly during the initial baking stage. Of course the amount of expansion during the initial baking stage will depend on the type of bread to be made. However, steam will enhance this as the dough expands during oven spring.
After all that, how can we get good quantities of steam at the right moment?
I’ve tried a few ways but in my opinion the best way is as follows.
Keep a small stainless steel bowl in the bottom of the oven baking chamber near the oven door so it’s easy to fill with boiling water. Since this bowl lacks thermal mass we must provide it. Use heavy stainless steel nuts and bolts or thick stainless steel chain links that fit into the bowl. Stainless steel is best as mild steel will oxidise (rust) very rapidly but the cheaper option of mild steel will work just fine.
This apparatus stays in the oven on pre-heating. This will ensure that when you need a receptacle, hot and ready, to generate steam with thermal mass it will be there.
This is how to make it work; once the dough is ready to bake, boil a jug of water. After slashing the dough piece load the oven with the dough. Immediately after loading pour the boiling water into the bowl quickly and quickly close the oven door. Steam will continue to be produced during the initial few minutes. This will condense on the dough surface effecting the desirable shine and bloom.
It can be a little tricky to smoothly coordinate these tasks, but a little practice and you’ll be just fine.
Here is a video showing Kon using his steam engine:
Here is the same dough baked with steam and without:
Here’s a good example of bread with good quantities of steam at the right time during baking. Note the colour brightness and the shine on the crust.
If you want the best appearance and the satisfaction of the best results on your home creations, take a bit of time to get your steam generator working. You’ll be amazed at the results. Good luck!