Since that time Koltz has evolved and now specialises in Shiraz and Shiraz blends from the McLaren Vale region, renowned for its Shiraz wines worldwide. Mark Day has worked as a wine maker for Maxwell Wines and Wirra Wirra in McLaren Vale and as a consultant in Italy and France over the last 6 European vintages.

Koltz are located on a scenic vineyard in the Blewitt Springs region of McLaren Vale and are now in the process of building a small boutique winery. Mark Day has worked as a wine maker for Maxwell Wines and Wirra Wirra in McLaren Vale and as a consultant in Italy and France over the last 6 European vintages.

Koltz is a very small producer and all their wines are hand crafted using traditional methods; fermented in open vats and when dry, basket pressed and put to oak. Koltz try to make wines that are individual and reflect the winery's philosophy that wines should be complex but a pleasure to drink at any stage of their evolution.

Their estate wines will reflect another phase of Koltz evolution, combining individual attention and European experience with Australian style based on Shiraz from their own vineyard. McLaren Vale is situated 40 kilometres south of Adelaide in South Australia and has a Mediterranean climate with an annual rainfall of approximately 650 mls. It stretches from coastal plains to the foothills of the southern Mount Lofty ranges and this creates variation in both altitude and terroir.

Different soils and micro climates produce different wines. The vineyards of Blewitt Springs are generally sand on ironstone gravel and just under 200 metres above sea level. As a result the Shiraz from this area is elegant with fine silky tannins and good length and mouth feel. Koltz also sources grapes from vineyards in the Willunga region of McLaren Vale where the soils are darker deep clay and loam and produce more robust, richer wines with firmer tannins.

"Mark Day and Anna Koltunow released their first wine in 1995, using grapes from the Bottin Vineyard in McLaren Vale. Mark Day had worked as winemaker at Maxwell Wines and Wirra Wirra in McLaren Vale, and has been a Flying Winemaker for six consecutive vintages in Europe. Day and Koltunow decided to specialise in Shiraz and Shiraz blends from the McLaren Vale region, but added Sangiovese and Mourvedre to the mix in 2002." -James Halliday