Growing Shiraz in Australia likely begins with the first plantings. The variety thrived and became the base of the fortified wine business especially for ports, high sugar content sherries and the medicinal table wines which were shipped to the U.K. Cabernet does not have the same history and while old vineyards survive, they are few. Cabernet is the base for the English wine Claret so when table wines expanded in the 1940s and 1950s and with Cabernet being in short supply Shiraz was used to expand the quantity. These two varieties are not seen as natural twins in other countries, so this blend has become part of the Australian tradition.
Indeed, the best are now seen as legends and there is a show which only judges this blend. In warm climates, such as the Barossa Valley, Cabernet takes on a different taste and blending the two is seen as quite natural. The Penfolds Bin 389 is the leader in this field though the Signature blends of Yalumba are equals. The Glug Green Patch is a blend of wines purchased from local boutique grower makers-the number of which have considerably expanded in the last decades-with surplus stock now making its way into the market.