In book two when O'Brien offers Winston wine, why can't Winston taste the wine and why would Orwell consider putting in this detail?

The book offers a few reasons, and I think you might be
able to come up with more.

1. Winston has been drinking
straight gin as his only alcohol for years. His anticipation of wine was that it would
be immediately intoxicating (like a hard liquor), and incredibly sweet (like berries...
the color it protruded). He never had it before and had only read about it. He really
didn't know what to expect, but had built in an
expectation.

I think this detail is indicative of what is
to come. Winston can taste, so he believes, conspiring against the party. Freedom.
However, what is about to happen is nothing of the sort, sorry to spoil the
ending.

Wine is an acquired taste. One dose is not
pleasing. But after tasting a variety of wines, one becomes an expert and knows how to
experience each wine's benefits.

2. Gin, Winston's usual,
is taken like a shot. After being thrown to the back of the mouth, it is immediately
swallowed, not for taste, but for effect. He didn't know how to enjoy wine. This
experience shows that he knows very little about something very
normal.