The Moment of Truth
Over the course of just a few minutes, the result of hours of kneading, rising, folding, and shaping come to fruition. In many ways, baking bread is the most unpredictable aspect of the process. Every part of bread-making has several factors that affect each step—however, unlike many other steps, regulating the oven environment is more difficult and usually irreversible. The keys to mastering the baking process are understanding how your oven works and practicing often.
A Basic Explanation of Thermodynamics
There are three types of heat bakers care about: thermal radiation, convection, and conduction. Conduction is when heat is directly transferred from one surface to another. Cooking food on the stovetop is an example of this. Convection is the transfer of heat via particles (or liquid). Thermal radiation is the transfer of high-power electromagnetic waves through an empty medium. In most home ovens, the walls heat up and direct rays towards the surface of food; however, thermal radiation dissipates over distance.
Many sourdough recipes (including mine) call for cooking bread in a dutch oven as it reduces the distance between the loaf and the source of thermal radiation. Though bakeries traditionally use deck ovens with low ceilings, the heating elements in home ovens are far away from the objects they bake. To achieve the greatest oven spring, lots of immediate heat is required; dutch ovens have solid walls which retain heat and quickly transfer energy to loaves.
Thermal radiation
Convection heat is when fast-moving particles directly transfer heat to an object. Convection heat is more efficient than thermal radiation, as particles hit food directly. Convection ovens simply blow air around—in recipes like bagels, I suggest using convection mode if available as it quickly and evenly browns the bread. When sourdough bakes, water and gas particles escape the loaf—in a dutch oven, the particles are confined and bounce around at high speed, helping cook loaves more evenly.
Convection heat
Thermal conduction is when an object is heated through direct contact. The reason food browns well in a pan or on a sheet tray is because its surface absorbs energy directly from the metal. Pizza cooks directly on a stone to quickly create a crispy crust and chewy, moist interior, and doughnuts cook in oil because they can absorb lots of energy in a short amount of time.
Thermal conduction
Scoring Bread
Though often beautiful, bread scores serve a much more vital role than decoration. When introduced to sudden, intense heat, several reactions take place: yeast and bacteria speed up fermentation, releasing much more gas; already present CO2 and water expand and bounce around violently; like a water balloon, the strands of gluten stretch to contain the gases. However, gluten’s strength is not infinite. Gas always finds a way to exit bread—scoring a loaf simply helps control the escape of gas. If bread is not slashed, air may create large gashes along the side of the bread to escape.
A key mistake amateur bakers make is incorrectly scoring. A 750-1000g boule should contain at least one large slash, ¾-1 inch deep. A sign of a well-cut loaf is an “ear,” or a ridge of dough that has separated from the loaf and is heavily browned. When slashing a functional vent, you should try to cut at a low angle—the gases will have to work harder to escape and will create an even larger oven spring and larger ear. Feel free to make several decorative slashes, but make sure they are shallow or else too much steam may escape. The final key to scoring is to use a very sharp blade, ideally a razor or bread lame. If the blade gets caught on the dough, try cutting faster or dusting the surface of the loaf with a bit of flour.
Using The Correct Baking Vessel
Professional bakers have the luxury of using specialized ovens with steam injection, high heat, and alternative sources of fuel (think: a wood-fired pizza oven). Home bakers must make do with what we’re given. There are a few simple ways home bakers can replicate the effects of a professional bakery, however. Whereas pizzerias use high-powered, incredibly hot ovens to fire pies, we can replicate the effects at home by bringing the pizza closer to the source of thermal radiation and using a baking stone to quickly cook the crust via conduction. For other loaves, less heat-retention is preferable.
For enriched breads such as brioche, try to use metal baking dishes, as glass can retain too much heat and overcook the delicate breads. Lastly, a dutch oven (or any metal or ceramic baking dish) is crucial to achieving bakery-quality sourdough. Home ovens constantly replace their air, removing steam from the environment, but dutch ovens retain steam and provide a much stronger source of thermal energy.
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