DNA fingerprinting has proven that Cabernet Sauvignon is derived from a cross between Cabernet Franc and Sauvignon Blanc which probably happened spontaneously in a vineyard in France (probably in the Médoc/Graves region) sometime in the 18th century. Very small, intense blue berries with thick skins which provide deep color, intense tannins, and a high concentration of phenolics. This variety ripens late and so requires significant heat to grow successfully. Aromas are often described as blackcurrant and green bell peppers. The intense profile and structure of Cabernet Sauvignon wines make aging in oak a necessity. Blend with Merlot, Cabernet Franc, Petit Verdot, Carmenère, and Malbec for a Bordeaux or Meritage style wine with great depth and complexity.