grating just doesn't seem to work as well and/or 'keep'. I have tried both and the oil recipe is the strongest by far. I simply ground up a bunch of cloves in my vita-mix blender with oil right in their with it. Then I covered it and let it sit for a few weeks. It got so strong that it smelled up the back yard, OUTSIDE! heh.
It is much stronger. However, I believe in always having some in my system, so EATING it is probably the best thing one can do. But the oil does work great topically.