In South Australia, around one hour drive from Adelaide, lies the Barossa Valley, where wines like the jammy Shiraz and the finest Riesling are produced. Australians are charming and open to visitors, therefore, there is plenty of wineries offering tastings. Furthermore, you could go for free tours and have lunch in local eateries, where there is real farm-to-table food of highest quality. Ideal to visit is the Yalumba, the oldest family run winery of Australia, offering a nice tasting room with fireplace, ideal to taste some wine.
In general, most of the wineries offer for tasting 6 to 12 wines. You should not taste them all, the best idea is to give the staff an idea of your preferences and let them suggest you the best ones.