Yes, you are correct. New cast iron pans typically have a rough and textured surface when they are manufactured. During the manufacturing process, the cast iron is often molded and may not have a perfectly smooth finish. As a result, the surface of new cast iron pans can be somewhat bumpy or uneven.
However, with regular use and proper seasoning, the surface of the cast iron pan can become smooth and non-stick over time. Seasoning involves applying a thin layer of oil to the pan and heating it to create a polymerized layer that protects the iron from rust and improves its non-stick properties. As the pan is used and the seasoning layers build up, the cooking surface becomes smoother and more seasoned, leading to better non-stick performance.
The process of seasoning and use causes the oils and fats to fill in the gaps and irregularities on the surface of the cast iron pan, leading to the development of a smooth and seasoned cooking surface. The more the pan is used, the better the seasoning becomes, and the smoother the surface will be.
Old and well-seasoned cast iron pans are highly prized for their non-stick properties and even heating distribution, making them excellent cookware for a wide range of culinary tasks. It's essential to properly care for and maintain cast iron cookware to keep it in good condition and maintain its smooth surface over the years.