"100% pure orange juice"

The phrasing on the label is clearly awkward (presumably they mean it's a mixture of orange juice concentrate and unconcentrated orange juice).  But as I pondered the photo, I also began to wonder whether the other phrase - "100% pure" - is grammatically correct or not.

My dictionary defines "pure" is defined as "free from anything of a different, inferior, or contaminating kind," unmodified, homogeneous, absolute, untainted, virgin, etc.  With that understanding, is "pure" an absolute term, like "unique," and is "100% pure" unnecessarily redundant?  Can something be 90% pure? 40% pure?

This is certainly not important.  It's the sort of stuff that English majors, wordfreaks, and copyeditors like to puzzle over. 

Found at Video Martyr, a blog featuring posts about ephemera and urban archaeology.

Addendum: And a hat tip to Max, who found this related item at Consumerist:

Even though it says "not from concentrate," it probably sat in a large vat for up to year with all the oxygen removed from it. This allows it to be preserved and dispensed all year-round. Taking out all the O2 also gets rid of all the flavor. So the juice makers have to add the flavors back in using preformulated recipes full of chemicals called "flavor packs."