the word "את" in this sentence doesn't mean "you" and is pronounced as et (singular female 'you' is pronounced at). I really don't know how to explain the "את" in this sentence, since it's a concept that doesn't exist in english, but basically it's specifying that the wine is not some random wine, but a wine that the listener is aware of. It's not a definite article ("the" in english), the "ה" in "היין" is, instead it's complementing the definite article. I hope this isn't too confusing, I really have no idea how to explain this, I just know when to use it by instinct, but someone else can probably explain it better.

Edit: Okay, I just googled it and I think I have a better explanation, according to the wikitionary "את" is: "[a word] Used to introduce a semantically definite direct object." basically what this is saying is that "את" is used after a verb before a definite article, so if I want to say "I like dogs", I would say "אני אוהב כלבים" (ani ohev klavim), but if I wanted to say I "like THE dog", then it would be "אני אוהב את הכלב" (ani ohev et hakelev), further more, if I wanted to say "I like THIS dog", then I would just add "this", "הזה", at the end of the sentence resulting in "אני אוהב את הכלב הזה" (ani ohev et hakelev haze). I hope this explains this better.

P.S. "את" isn't used after the verb "to be" because it doesn't exist in Hebrew, so "he is the teacher" would be "הו המורה" (hu hamore).