Cabernet Sauvignon - Viticulture

Viticulture

While Cabernet Sauvignon can grow in a variety of climates, its suitability as a varietal wine or as a blend component is strongly influenced by the warmth of the climate. The vine is one of the last major grape varieties to bud and ripen (typically 1–2 weeks after Merlot and Cabernet franc) and the climate of the growing season affects how early the grapes will be harvested. Many wine regions in California give the vine an abundance of sunshine with few problems in ripening fully, which increases the likelihood of producing varietal Cabernet wines. In regions like Bordeaux, under the threat of inclement harvest season weather, Cabernet Sauvignon is often harvested a little earlier than ideal and is then blended with other grapes to fill in the gaps. In some regions, climate will be more important than soil. In regions that are too cool, there is a potential for more herbaceous and green bell pepper flavours from less than ideally ripened grapes. In regions where the grape is exposed to excess warmth and over-ripening, there is a propensity for the wine to develop flavours of cooked or stewed blackcurrants.

The Cabernet grape variety has thriven in a variety of vineyard soil types, making the consideration of soil less of concern particularly for New World winemakers. In Bordeaux, the soil aspect of terroir was historically an important consideration in determining which of the major Bordeaux grape varieties were planted. While Merlot seemed to thrive in clay and limestone based soils (such as those of the Right Bank regions of the Gironde estuary), Cabernet Sauvignon seemed to perform better in the gravel based soil of the Médoc region on the Left Bank. The gravel soils offered the benefit of being well drained while absorbing and radiating heat to the vines, aiding ripening. Clay and limestone based soils are often cooler, allowing less heat to reach the vines, delaying ripening. In regions where the climate is warmer, there is more emphasis on soil that is less fertile, which promotes less vigor in the vine which can keep yields low. In the Napa Valley wine regions of Oakville and Rutherford, the soil is more alluvial and dusty. Rutherford Cabernet Sauvignon has been often quoted as giving a sense of terroir with a taste of "Rutherford dust". In the South Australian wine region of Coonawarra, Cabernet Sauvignon has produced vastly different results from grape vines planted in the region's terra rosa soil – so much so that the red soil is considered the "boundary" of the wine region, with some controversy from wine growers with Cabernet Sauvignon planted on red soil.

In addition to ripeness levels, the harvest yields can also have a strong influence in the resulting quality and flavors of Cabernet Sauvignon wine. The vine itself is prone to vigorous yields, particularly when planted on the vigorous SO4 rootstock. Excessive yields can result in less concentrated and flavorful wine with flavors more on the green or herbaceous side. In the 1970s, a particular clone of Cabernet Sauvignon that was engineered to be virus free was noted for its very high yields-causing many quality conscious producers to replant their vineyards in the late 20th century with different clonal varieties. To reduce yields, producers can plant the vines on less vigorous rootstock and also practice green harvesting with aggressive pruning of grape clusters soon after veraison.

In general, Cabernet Sauvignon has good resistance to most grape diseases, powdery mildew being the most noted exception. It is, however, susceptible to the vine diseases Eutypella scoparia and excoriose.