Steaming and rye crust development
I believe that every bread should have a great crust. But different types of breads will have completely different crusts and their development techniques differ. Rye breads benefit from steamed baking just like wheat breads do yet steaming regiment is a bit different. If one tries to steam rye bread the same way it’s done with wheat breads, the end results might be unpleasant.
The best rye crust I’ve ever had in my life was on a coarse rye from small family owned bakery called Bemberi located in a small town of Saulkrasti, Latvia. Crunchy, slightly sweet and full of rye flavour!
Some of the techniques used by professional rye bakers are virtually impossible to replicate at home. This post covers the methods I’m using at home to get quality crust with common household tools.
Photos above show different rye breads from different European countries with long running rye baking traditions. Important thing to note in these images is that crust on rye breads is usually smooth, without cracks and ruptures, it is not scored and there are no “bread ears”. Some people prefer baking rye breads with ruptured crust and while no one is stopping you from doing whatever you want with your very own bread, I prefer to follow traditions of my home region and I personally consider ruptured crust a baking defect.
The science behind crust
The key to quality rye crust development is a proper steaming and temperature regiment during baking. Russian State Research Institute Of Baking Industry has posted a guideline on steaming, but it is in Russian. The following is a translation of this post.
Steaming has technological importance because it affects heat transfer rate from the oven into the dough.
Steam condensation on the surface results in starch gelatinisation and dextrin formation on the bread crust. This creates a thin layer which smooths out the crust and makes it glossy.
Lack of moisture will turn crust pale and matte looking.
Condensation at the start of the baking process improves elasticity and slows down crust hardening. Elasticity is required during this period to avoid crust rupturing and cracking because the dough continues to leaven during first minutes of baking.
Yet rye breads lack gluten, which can hold its own weight and volume even while being moist during slow crust formation. Thus prolonged steaming will result in a collapse of rye bread.
Practice shows that rye breads, especially stone baked ones, require steaming for just a few minutes.
Prolonged steaming might result in crust cracking and rubbery texture.
Initial steaming can be done:
- by using steam injection (in an oven with an injector);
- by adding a few ice cubes under oven tray;
- by adding a small amount of water in secondary oven tray;
- by spraying some water inside during dough loading;
- by wetting dough surface before loading.
Text on the images notes that steam should be released from the oven after just five minutes. It also notes pre-roasting method which is used in some traditional bakeries as well as modern factories in the region, but it requires temperatures above +300C and household ovens capable of supporting such temperatures without losing much heat during dough loading are very rare and expensive, so we can skip this method.
My experience shows that the best way to create a quality rye crust at home is to use a combination of different techniques. First step is a flour washing or surface wetting before dough loading, next one is water spraying into the oven during loading and slurry wash or crust spray after baking. Dough should also be pricked before loading. I usually use chopsticks to prick my bread and I make 3-4 holes in 600g loafs. Larger loafs require more holes. Holes should be vertical and should go all the way through the dough. Rye breads are never scored.
Flour wash adds a new layer of water and flour on top and usually is a requirement for specific recipes, while surface wetting can be used as an alternative way to introduce moisture for recipes that don’t require any washing.
Many breads are also washed with a starch slurry after baking, but those which don’t require such procedure can be simply sprayed with some water after baking.
Some breads are dusted with flour before baking. Such breads can not be washed. The best way to steam them is to use ice cubes or a tray of water inside the oven for first 5 minutes.
Flour wash is applied to the top surface of some breads. It is usually made from wheat or rye flour mixed with water. Different recipes call for different flour to water ratios, but in general wash consistency should resemble batter, not dough. Some recipes might call for a mix of bread dough and water instead, but the basic principle behind such wash is the same. Sometimes flour wash might contain flavourings, like milled seeds, spices and herbs. Wash is applied with a brush to cover the whole surface evenly. All cracks and holes which appeared during proofing should be smoothed out with flour wash.
This is the simplest way to add moisture. Simply dip your hands into water and carefully smooth out dough surface trying not to deflate it. The surface should become wet, but not soaking wet.
Spraying the oven
I find it to be the easiest way to introduce a limited amount of steam for the first minutes of baking. Just take a spray bottle, fill it with water, load your dough into the oven and spray inside 3-5 times. Make sure to avoid water contact with glass surfaces inside the oven (including glass door) or this glass can crack due to temperature differences.
Starch slurry wash
To make starch slurry, take a saucepan, add 5g of potato or corn starch to 150g of cold water and stir until dissolved. Put the pan on the stove and heat it up until boiling stirring non stop. Once boiling starts, remove from heat and let it cool down.
Slurry wash is applied to hot bread right after you take it out of the oven. Use a brush to spread it evenly. Water will evaporate rapidly leaving your bread with a thin starchy layer which seals moisture inside the bread, adds a slight crunch to the crust and makes it glossy.
If you can’t make starch slurry, you can also spray some water on the surface of the loaf after taking it out of the oven. That won’t seal the moisture inside, but it will at least add some gloss to the crust. If you spray too much water, put your bread back into hot oven for 5-10 seconds to dry out.
There’s no magic behind a good rye crust and you don’t really need fancy and expensive tools to develop it. You don’t even need a casserole dish! The main challenge is to find the appropriate amount of steam for your oven. Large volume ovens will require a lot bigger steam amount than a small oven. Use this post as a guide and feel free to experiment to find your way of creating great smooth, crunchy and glossy rye crusts!