Viticulture & Winemaking 101 – The importance of the terroir is fundamental to obtaining a high quality wine. In this context, terroir means to reject the more fertile soils in favor of leaner ground. The reality is that the Post House farm was originally viewed as a marginal farm in the perspective of its potential as an agricultural unit. It is only when producing wine from the grapes as opposed to selling the grapes, that the marginal aspect of the fertility of the soil becomes a positive. The marginal aspect results in vines that are more in balance, without being excessively vigorous and the associated drawbacks of high yields and shaded fruit. Excessive canopy shade causes a decrease in bud fertility, sugar concentration, color density, flavor and tartaric acid while it increases potassium concentration, pH and malic acid. During Viticulture & Winemaking, A balanced vine results in a good balance between alcohol and acidity and this is what we strive for in the vineyard.
The vineyard is planted at the foothills of the Helderberg Mountains and has a gently westerly sloping aspect for the red cultivars and a cooler southerly sloping aspect for the Chenin Blanc vineyards. The soils comprise mainly of a conglomerate gravel of around 70cm to 1m deep onto a clay base. This gravel soil is known as “cool ground”. This is because the gravel acts as a 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, as opposed to simple irrigation.
The foliage is a very important element of the vine, as it is the factory of the vine as well as the moderator of the sun’s rays on the bunch zone. It is important to have sufficient leaves to ripen the grapes to their optimum without over shading the bunches. The trellis system is a 4-6 wire vertically trained vine 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 color in red wine. Viticulture & Winemaking process means the leaves are further removed on the south side of the vine around the bunch zone further increasing the exposure of the grape bunches to the gentle morning sun.
As the vineyard is on high moisture retaining soil, irrigation is only used as a supplementary source of water, mostly at véraison and to nudge the harvest towards optimum berry maturity.
The first observation made about the wines is often the colour. These are perhaps some of the darkest, deepest colored wines to be found. This is a result of a combination of the terroir and vinification process.
The cellar only produces a small quantity of wine and assumes a hands-on and conscientious approach at each step. With creativity, the whole wine package is fine-tuned.
Interference is kept to a minimum during the wine making process. Therefore, the grapes are handled as gently as possible. The grapes are harvested into small fruit bins, where they are checked and sorted before being lightly crushed and destalked.
The red grapes are fermented in open stainless steel tanks using naturally occurring yeasts from the vineyard. Fermentation temperatures are 28 – 30° C. By using indigenous yeasts, the wine displays the unique character of the terroir and vineyard. The skins are punched down 4 – 8 times during peak fermentation. Malolactic fermentation takes place in 225L French barrels. During the following 18 to 20 months the wine enjoys minimal handling and it is allowed to evolve, stabilize and integrate with the wood. Sulfur levels are kept to a minimum and therefore the preservation of the wine and its development are balanced. The wines are racked using gravity flow and no mechanical pumps are used. Racking of the wine assists in the pro-active development of the wine as well as removing unwanted sediment that settles out. There is no filtration and only a light egg white fining prior to bottling.
The white grapes are crushed and left on the skins for a 2 hours contact period. The must is settled for 1 day in a settling tank and then racked straight to barrel where it will ferment. The aim is to keep air contact to a minimum, which helps in the retention of the fruit character of the wine. The grapes are fermented with naturally occurring yeast from the vineyard. The grapes are harvested in the cool hours of the day. This, along with the use of indigenous yeasts, causes a gentle and cool must fermentation at around 17°C-19°C. The wine is left on the lees and stirred initially once a week, and then every third week. Thereafter the wine is fined with bentonite, but not filtered, before bottling. Sulfur levels are kept to a minimum.