Ok,

I can't answer your questions for the poet, but I will try to explain how I understood his intention.

Do I really have to wait until I feel tipsy to know a wine?  ==> Yes, that is point. I believe that is how he felt.  Why didn't he say knew a wine by smelling it or getting drunk?


Isn't a fully-bloomed flower beautiful? ==> Yes, it is beautiful, but it is completely irrelevant to the poet we are discussing.  Of course, you can write a poem praising the beautifulness of a flower in full-bloom.  I bet the poet won't come out from the tomb arguing for half-blooming flowers.