Many of the local restaurants and cafes serve "traditional" German-heritage food, and food made with locally-grown fresh ingredients. Examples include 1918 in Tanunda and the Krondorf Cafe at Kabminye Wines. Fine dining choices include Appellation (http://www.appellation.com.au) in Marananga and Vintner's Bar and Grill in Angaston.
Many of the vineyards also serve food, from cafe style casual to full service restaurants.
Plan on eating at structured times 12PM to 2PM and 5PM-8PM, as many restaurants, pubs and vineyards do not serve meals through the afternoons.