The Limestone Coast GI (Geographical Indication) in South Australia is located in the south-eastern corner of the state, bordering Victoria in the east. It is one of the most significant wine zones of the country, producing nearly one-third of South Australia's quality wines – some of which are the most highly acclaimed in Australia. The Limestone Coast received its GI status in 1996.
The zone is regarded as geologically unique and the feature responsible for producing such high-quality wines is its soil. As the name suggests, limestone forms the basis of the soil here, best represented by the famous 'terra rossa' of Coonawarra. The limestone soils are well-draining and rich in nutrients, with a healthy water table beneath the sub-soil – unlike many other South Australian wine-producing areas. This means that most irrigation needs are taken care of, which is vital in the dry ripening season.
Limestone Coast's climate is cool maritime, although the inland north-eastern parts may experience some continental effects. Altitude does not have a major impact on the local climate as the grape-growing areas lie no more than 492ft (150m) above sea level. The lowest vineyards, near Cape Jaffa, are at an elevation of 33ft (10m). The vines are cooled by sea breezes during summer, resulting in cool to mild growing conditions with a slow and long ripening process. This extended hang time assists in the development of intensity in the grapes' fruit flavors.
A wide range of grape varieties of both colors perform exceedingly well in the Limestone Coast, but its red wines are of particular importance. Cabernet Sauvignon produces some of the most sought-after wines, with Shiraz and Merlot also prominent. The cooler parts of the zone are suitable for white varieties such as Chardonnay, Sauvignon Blanc, Riesling and Viognier.