All the mortars I've ever seen are smooth.
And anyway, doesn't a rough surface make it difficult to clean and give rise to cross-contamintion and carry-over of flavours from one cooking session to another?
--Roses2at 14:49, 25 July 2010 (BST)
I did have a marble one that was rough, and good. However, you're probably correct so I'll give you this one. --Chef 12:54, 26 July 2010 (BST)
No, you don't have to give me your pestle & mortar set at all.........(oh, you didn't mean it like that, rather you are conceding the point). Personally, I've never had or used a P & M in the kitchen, but we do have one at work which I occassionally use to mix and grind certain chemicals together. --Roses2at 07:47, 27 July 2010 (BST)