|VITICULTURE AND TERROIR
Until the early 1980s, the Post House site had a mix of tobacco and bush vines, where after it was systematically planted to vines. The property covers a total of 71 hectares of which 45 hectares is used for vineyards. Cultivars were selected to suit the terroir and, since 2007, the vineyard comprised of Cabernet Sauvignon, Merlot, Shiraz, Petite Verdot, Pinotage, Chenin Blanc and Viognier.
The concept of the terroir is fundamental to making a high quality wine. Using leaner soil, rather than more fertile soil, results in a more balanced vine. The more fertile the soil, the more vigorous the growth; this leads to the associated drawbacks of high yield and shaded fruit. At Post House we have the advantage of leaner soils, resulting in wines with a good balance between the levels of alcohol and acidity.
The vineyard is planted on the foothills of the Helderberg Mountains. The red cultivars are planted on a gentle westerly slope while the Chenin Blanc enjoys a cooler southerly slope. The soils mainly are a conglomerate gravel of 70cm to 1m on a clay base. This gravel soil is known as ‘cool ground’. This is because the gravel acts as natural mulch, shading the vine roots from the sun. The gravel /clay combination acts like a sponge, storing water during the rainy season and redistributing it back to the roots in the dry season. This ensures constant feeding of the vines, giving them a more balanced water source than simple irrigation would supply.
The foliage is a very important element of the vine. It is both the energy factory of the vine as well as a moderator of the sun’s rays in bunch zones. It is important to have sufficient leaves to ripen the grapes to their optimum while not over shading the bunches. The trellis system is 4-6 wires for vertically trained vines known as the Vertical Shoot Positioned Trellis. Shoots are trained up allowing the sun to filter through onto the grape skin, which is essential for the development of ripe tannins and colour in red wine. Furthermore, leaves are removed on the south side of the vine around the bunch zone thereby increasing the exposure of the grape bunches to the gentle morning sun.
As the vineyard is on high moisture-retaining soil, supplementary irrigation is only used at véraison and to nudge the harvest towards optimum berry maturity.