For those of you who don't know, cork is a natural product that grows like bark on trees. This cork is farmed & harvested in places of the world like Spain & Portugal. It is then processed for various uses in many different industries. The cork that we use in the rod business is usually cut into round rings of certain sizes & cleaned during processing.
So there doesn't seem to be a danger of us running out of cork anytime soon. However, I have noticed that the very highest grade cork is harder to find these days. I'm talking about the cork that has absolutely no flaws in it at all - no holes or cracks of any kind.
A while back it became the trend to have totally flawless cork on some high-end rods. I never went along with this trend because, to me, grips made form perfect cork never looked right. Cork is a natural product & so it should have a few lines & small voids here & there. This is what you see on every classic rod, too. Grips made from perfectly flawless cork always looked fake to me. I mean, after all, if you wanted a grip that didn't show some of the natural beauty of the cork, you could make the grip from some synthetic material that would work just as well. But that takes some of the natural "mystique" away from the rod if you ask me.
Now, I'm not advocating that you should accept a cork grip that has giant craters in it or is so rough that chunks fall off as you fish with it. No, that would be bad. I do think though, that cork that has some natural striations in it that shows you have a natural product on your fly rod. It shows that parts (or all) of your fly rod was made by human hands & not some machine. Like the grain of the wood in a reel seat spacer, the minor, natural imperfections in a cork grip can show the natural beauty in the material.