"Ir a" is used for going to a place and "ir en" is used for going somewhere in a means of transport.
- Voy en bicicleta al trabajo.
- Vamos en auto a la playa.
- Fuimos en patines a la cafetería.
- Mis amigos van en avión a Francia.
"Ir de", although not used in all Spanish-speaking regions, is used for activities like wandering from one place to another.
I suppose here, "ir de vinos" means that you are going to visit places where a variety of wines are served, and you're tasting several of them. (I'm not sure about the complement for that sentence. I suppose someone would just say something like "hoy vamos de vinos". And then tell whether they're going to one bar or to several places.)
"Ir de" is also found in "ir de tiendas" (to go shopping), which implies wandering from one store to another.