Bread, or any food for that matter, is baked or cooked by heat. In this article, we will be exploring “bread under fire” – not specifically how to bake during a war but rather the effects of different kinds of fire (or heat) and their interactions with the bread baking in your oven. At the end of the article, I will attempt to show how baking might perhaps be the perfect activity to undertake at this troubled time.
In today’s modern ovens, the heat source is usually an electrical element. Many around the world still use gas rings for cooking, but gas-heated ovens are the exception and electrical ovens the rule.
Regardless of the heat source, the principles of heating are the same. They are radiation, conduction and convection.
Radiation occurs in waves. The heat source radiates electromagnetic waves at the object being heated, increasing the vibration of its molecules and thus causing the object’s temperature to rise. Our bodies radiate heat, the sun radiates heat, and the electrical element in the oven radiates heat.
Conduction is the transfer of heat from one molecule to another. In a hot substance, molecules are vibrating at a high rate. If a cooler substance contacts the hotter substance, the molecules of the hotter substance will agitate the cooler molecules, which then also begin vibrating at a higher rate and heat travels, or is conducted. Some substances conduct heat well, such as copper, while others conduct poorly, like air.
When you place a metal baking pan on a hot oven tray, heat is transferred from the oven tray to the baking pan and subsequently to the bread in the pan by conduction.
Convection is the transfer of heat in a gas or a liquid. Air is a poor conductor of heat, and only the air immediately adjacent to the heat source will be effectively heated (by conduction). To effectively heat the air in the oven chamber, movement is necessary. This is achieved by a fan in the oven chamber that fans the heat and distributes it evenly to all parts of the oven.
The three principles of heating – radiation, conduction and convection – all occur simultaneously in your oven.
That’s the physics, but how does this help the home baker? We know that bread bakes from the outside in. The convective heat being fanned in the oven and conductive heat from the baking pan are transferred to the bread from the periphery towards the center.
The trick of successfully baking bread is achieving the “fully baked” state in the center of the loaf before the crust begins to burn. If the outside of your loaf is burning while the inside is not yet fully baked, the thermodynamic balance in your oven is not optimal.
If the entire outside of the loaf is burning before the inside is fully baked, simply reduce the overall oven temperature.
If the underside of the loaf is burning, this is because it is hotter below than above.
Since most ovens do not provide individual control over upper and lower element temperature, you need to reduce conductivity on the bottom by changing the conducting medium, perhaps from a metal pan to an earthenware pan, which conducts heat more slowly.
If the upper side is burning before the bread is baked, then you have the opposite problem: It is hotter above than below. You can prevent this by increasing conduction below by using a metal pan. If you already use a metal pan or tray, reduce the heat from above by reducing convention – i.e., by switching off the fan.
Using a baking (or pizza) stone in your oven will help to accelerate baking time and achieve more even baking. Baking stones provide increased radiation energy and also produce radiation waves of a longer wavelength than those generated by an electrical element. These long waves penetrate the bread more easily and bake it faster. For optimal results for flat breads such as pita, pizza and focaccia, one stone below is sufficient.
For larger loaves, a stone above and below is recommended.
To wrap up, I would like to devote two words to the title. In this period when we are cooped up at home with the kids, a little family baking is an ideal way to strengthen family bonds and alleviate the tension.
Be safe and enjoy your baking.
Makes two 60x40-cm. platters Focaccia is Italian flatbread.
Biga (preferment): ✔ 3 cups flour ✔ 1¼ cups water ✔ 1 pinch (a quarter of ½ tsp.) instant powdered yeast ✔ 2 tsp. salt Mix, cover and leave to rise for 12 hours.
Final dough ✔ 8¾ cups flour ✔ 3¾ cups water ✔ 2 tsp. instant powdered yeast ✔ 1½ Tbsp. salt ✔ 1⁄3 cup oil Mix final dough ingredients together with biga and knead for 10 minutes. Leave to rise for 2 hours, punching down each hour. Divide into 2 pieces. Flatten each piece to cover a 60x40 cm. baking tray. Spread with olive oil garnished with rosemary, garlic and coarse salt (alternatively use pizza sauce and grated cheese). Leave to rise for 1 hour.
Heat oven to 280° C. Bake for 10 to 15 minutes or until golden brown.
Master baker Les Saidel is CEO of the Saidel Artisan Baking Institute (www.saidels.com). The SABI offers baking workshops year round and during the summer vacation for families and groups.