You do not need a special ticket for admission to Epcot for the Food & Wine Festival. There are a number of special events that are "hard ticket" or have a separate admission to the event. Not all of those are held inside Epcot, but if they are, many of them also require you to have Epcot park admission (like the Party for the Senses - although you pay separately for admission to the party, you can't access it unless you also have Epcot park admission. Tickets were not issued for any of the special events, cast members checked attendees off on a list. On the other hand, the Wine School event does not require Epcot admission. If you don't have Epcot admission they will tell you to check in at the park gate and escort you to the event, and they'll also escort you back out if it's a daytime event and the park is still open when it ends).
I am not sure which type of wine pairing class you are considering attending - the half-hour seminars at the festival center or the "hard-ticket" events that can last a few hours. The wine seminars in 2009 cost $8 per person and tickets could be purchased ahead of time or in the festival center after you arrived. You were not provided with an actual ticket if you booked ahead of time; they checked your name off on a list. There were limited discounted seats at $5 for each seminar applicable to DVC members, TIW members or annual passholders and those had to be purchased ahead of time via the Internet. There were also wine pairings held at some of the restaurants, and tasting events like wine schools. These are purchased through WDW-DINE and paid in full upon booking.