The decision to first start blending Cabernet Sauvignon was partly derived from financial necessity. The sometime temperamental and unpredictable climate of Bordeaux during the "Little Ice Age" did not guarantee a successful harvest every year; producers had to insure themselves against the risk of losing an entire vintage by planting a variety of grapes. Over time it was discovered that the unique characteristics of each grape variety can complement each other and enhance the overall quality of wine. As a base, or backbone of the wine, Cabernet Sauvignon added structure, acidity, tannins and aging potential. By itself, particularly when harvested at less than ideal ripeness, it can lack a sense of fruit or "fleshiness" on the palate which can be compensated by adding the rounder flavors of Merlot. Cabernet franc can add additional aromas to the bouquet as well as more fruitiness. In the lighter soils of the Margaux region, Cabernet-based wines can lack color, which can be achieved by blending in Petit Verdot. Malbec, used today mostly in Fronsac, can add additional fruit and floral aromas.