The red grape variety (breeding number Walker 09331-047) is a complex, interspecific new breeding between varieties of the species Vitis vinifera (97%), Vitis rupestris (1.5%) and Vitis arizonica (1.5%). The Vitis vinifera varieties were Zinfandel (50%), Petite Sirah = Durif (25%) and Cabernet Sauvignon (12.5%). The crossing was done in the 1990s by the geneticist Dr. Andrew Walker, professor at the University of California in Davis. The late-ripening vine is extremely resistant to Pierce Disease, a vine disease that is becoming more common due to climate change. It produces dark red wines with soft tannins and a variety of aromas of blackcurrants, berries, black olives, herbs, liquorice and dried hay.