Doug D
TVWBB Hall of Fame
Just got off the phone with Lodge, and they said the rougher surface texture is due to a change in the way their molten metal is poured. In the older days, it was all done by hand, and it caused imperfections that had to manually smoothed out.
Now-a-days, pouring molten metal is done by machine, and it eliminated the need for removing imperfections. I was also told that pans with rougher textures will season quicker than smoother pans, and the seasoning procedure itself is a "years long" process. And it is entirely possible to render a cast iron pan unseasonable if one tries to "polish" the finish themselves with a power tool. At least that is what I was told.
High speed automated molding doesn't allow for the mold surface preparations commonly used in the hand pour era. Finer sand was used in those days also. Both resulted in relatively far smoother castings right out of the mold. You can successfully season an unpolished modern day Lodge pan, but years long is a bit of an exaggeration. True, though, is that a pan can be over-polished. If you've ever seen NOS pans from the mid-20th century, the spiral of fine polishing marks is evident, and they do actually help seasoning to stick. But a fine mirror polish does seem to make it more difficult to do so. Late 19th century all the way to about the mid-1970s, cooking surfaces of those pans that could be mounted on them were polished on spinning grinding machinery. But it was always touted as a value-added extra finishing step, not a band-aid for any hand casting shortcomings.