The wines are from different years
   If you apply an arbitrary order to the bottles, the number of possible year-arrangements of the bottles is 16!
   Each test gives you one bit of information
   Since 2^50 is only greater than 16! by about 50x < 2^6, you only have about 5 tests to spare.
   There's probably some clever way to express the solution beyond just the brute force the above implies, but I haven't thought about it past this point