The surface of a cast iron skillet does not necessarily have to be rough, but a rough surface is often preferred by many cooks and chefs. Here's why:
Non-Stick Properties: A rough or textured surface on a cast iron skillet provides natural non-stick properties. When the skillet is properly seasoned (a process of applying and polymerizing oil to create a protective coating), the rough surface helps the oil adhere better, creating a smooth, non-stick cooking surface over time.
Enhanced Browning: The rough surface of a cast iron skillet allows for better browning of food. When you cook on a rough surface, there are more points of contact between the food and the pan, resulting in more even browning and better flavor development.
Improved Heat Distribution: A rough surface can enhance the overall heat distribution across the cooking surface. The irregularities in the surface help disperse heat more evenly, reducing the risk of hot spots and ensuring more consistent cooking results.
Better Searing: The rough surface promotes better searing of meats and other foods. The increased contact points between the food and the pan help create a nice crust, sealing in juices and flavor.
Traditional Appeal: Many enthusiasts and professional cooks appreciate the rustic and traditional look of a well-seasoned, rough-surfaced cast iron skillet.
That said, some modern cast iron skillets come with smoother surfaces, often achieved through additional finishing processes during manufacturing. While these skillets may require a bit more effort to develop a non-stick surface through seasoning, they can still be effective for cooking once properly seasoned.
Ultimately, whether you prefer a rough or smooth surface on your cast iron skillet depends on personal preference and cooking style. Both types can be effective and produce excellent results when used and cared for properly.