These show the oven’s capability to distribute heat. In a low-budget oven, you will most likely notice a difference in the browning of the baked goods in different areas of it. Often it happens near the heating element or at a regular radius from it. Some areas of the bread will be darker or paler than others. The effect of heat spots (sometimes called “hot spots”) becomes more exaggerated when the oven’s running at full capacity.
Using the fan in an oven when baking bread is generally a no-no. And it won’t fix a problem like heat spots. Having air blowing around stops pressure from being built up during the bake. Pressure is necessary when forming the shape of your loaf, it also removes moisture from the surface of the bread which destroys the oven spring and the prospect of a crispy crust. I found when trailing that a powerful fan will push the bread over as well!
In a commercial bakery oven, the baker is still going to have to deal with distribution challenges when it comes to heat. In the trade, they are referred to as heat spots. Similar to the issues found in low-cost ovens, but can also occur in smaller areas. These areas form heat pockets as well as areas of low heat. Heat spots can occur in recurring places even without a fan, the hot air circulates regardless. It can bounce off the products inside causing hot and cold spots to appear.
To counteract heat distribution issues during bread baking here are a few pro-tips that can help remove or reduce the issue: