Making sourdough is a complicated and time-consuming task. From feeding the starter, autolysing, mixing dough, thousands of folds, pre-shaping, final shaping, cold-fermenting, scoring to finally baking in the oven. You have spent countless hours and the bread turns out not as pretty as expected. It is totally frustrating. Many factors affect the outcomes. One of the reasons may be the lack of steam while baking.
The one on the left is baked without steam and the one on the right is baked with steam. You can see the results are completely different.
Creating steam during the early stage of baking is the key not only to great oven spring but to that beautiful thin crisp crust.
What is oven spring
As the heat from the oven transfers to the dough, the vapor (from water or other liquid in the dough) and gases (alcohol or carbon dioxide from baking soda/ baking powder/ yeast fermentation) start to expand in volume. Besides gases, the air bubbles in the dough also enlarge and push the cell walls, forcing them to stretch and thus leaven the bread. This is what we call an “oven spring”. Oven spring happens at an early baking stage, usually the first 10 to 15 minutes.
How adding steam can level up your sourdough game
Crusts form fairly quickly as the heat transfers from the surface of the dough to the center. Once the crust is formed, the dry and hard surface will prevent the bread from expanding. The air and gases inside may crack the surface but they will no longer leaven the bread, resulting in tighter crumbs and thicker crusts. On the other hand, with added steam, the surface of the dough will stay moist and flexible. The bread will continue to rise for a longer period and the final product will have a softer texture, wilder crumbs and thinner crusts.
How to create the best environment for sourdough baking
Generally there are two main methods to create steam – bake in open or closed. When baking in the open, we add steam to the oven. While baking in close, the closed environment enables to hold the water/ vapor/ humidity from the dough in the baking vessel and thus we have the steam.
Method #1 Open Bake with a roast dish/ baking stone/ baking steel
You will need a heavy-duty deep roast dish like the one in the picture and another baking tray. The heavy-duty roast dish is for the bread. The other baking tray is for catching boiling water to create steam. When preheating the oven, leave both the roast dish and baking tray in the oven too. I usually leave the baking tray (for steam) at the bottom layer and the roast dish at the lower middle layer.
Boil some water before the oven is ready. When the oven is ready, score the bread and transfer it to the roast dish. Quickly and carefully pour some boiling water into the baking tray at the bottom layer. Close the oven door. Bake at 250 degrees for 20 minutes. After 20 minutes, take out the bottom tray(may have some water left) and lower the temperature to 230 degrees, continue baking to the preferred colour.
* roast dish can be substituted with baking stone or baking steal
* for the bottom tray, you can also leave a towel or two in (or use a cake tin) and let the towel absorb boiling water. This way, steam lasts a bit longer.
* instead of tea towels, use lava rocks. Lava rocks can be heated up to extremely high temp. Once the boiling water is poured onto those rocks, you won’t be worried about not having enough steam
* for ultimate effect, get both tea towels and lava rocks in action. at the bottom, one side is a tray with lava rocks and the other side is a tray with tea towels
Method #2 Closed Bake With A cast iron pan/Dutch oven/Pyrex dish
For this method, you will need either a cast iron pan, a Dutch oven or a Pyrex dish. Basically, anything that has a lid and is oven-safe can be used here. For me, I like my cast iron bread pan as it contributes heat evenly and this bread pan is designed specifically for bread – it has a shallow base for easy bread-transferring.
When preheating the oven, leave the cast iron pan/Dutch oven in the oven to preheat as well. As long as the oven reaches the desired temperature, score the bread and carefully transfer the dough to the baking vessel. Close the lid and put it back into the oven. I usually bake at 250 degrees with a lid on for about 20 minutes and at 230 degrees without a lid until golden brown colour.
* to achieve the best result, chuck two ice cubes into the cast iron after the bread is loaded. It instantly generates steam!
* I have tried baking sourdough in a Pyrex dish with and without preheating. Personally I prefer the result with preheating.
Pros and Cons
- open bake requires more equipment to create steam
- open bake allows baking multiple breads at the same time (using baking stone/steel)
- closed bake is more efficient in terms of creating steam
- cast iron pans/Dutch ovens are quite expensive and relatively heavy to carry
- cast iron pans/Dutch ovens are limited to 1 or 2 pieces of bread per bake
For home bakers, creating steam is not difficult at all. Let’s get the sourdough baking with lots of steam. Wish you all the good bread!
