Read time: 2 Minutes Cabernet Sauvignon, a key grape in Bordeaux Blends, is a hugely versatile grape and one winemakers combine with other grapes to produce a wide range of wine styles. Its characteristics help boost the weight, flavour intensity, colour depth and ageing ability of a wine blend. What does this have to do with Bordeaux Blends? Cabernet Sauvignon along with Merlot are the two principal grapes used in Bordeaux wines. Because it has a much harder time ripening in cool climates, Cabernet Sauvignon will generally produce a wine that is dark and strong but tannic. In some parts of Bordeaux like the Left Bank, where there is more ripening potential, Cabernet Sauvignon can thrive and produce beautifully dark and strong wines that are much fruiter and less tannic than in other areas in Bordeaux. Bordeaux winemakers adapt the wines they are making to their particular environment by blending. They will often use small amounts of Cabernet Sauvignon to intensify lighter, Merlot predominant wines in cooler regions and modest wines. Conversely they will use small amounts of Merlot to soften the brute force of Cabernet Sauvignon in warmer sites and premium wines. So that's Bordeaux, but how much Cabernet Sauvignon is blended in other regions? A wine labelled as Cabernet Sauvignon will rarely be 100% Cabernet as the laws of most winemaking countries allow a wine to contain 15-25% of another varietal without declaring it on the label. Only Cabernet Sauvignon from very warm climates will ripen enough to be pleasing on its own. Everywhere else, it will be blended with other varietals to make a more pleasing wine. And how does Cabernet Sauvignon bode in these blends? Traditional Bordeaux blends (modest quality) A little Cabernet Sauvignon adds colour, body and flavour without dominating. Typically used to boost lighter wines in cooler regions as in Merlot-based Bordeaux, but also in many Italian and Spanish reds. Traditional Bordeaux blends (premium quality) Cabernet Sauvignon is the principal varietal used but other grapes are used to soften the wine and offset the austerity of the Cabernet. Many of the world's finest reds are included in this category but cannot be labelled as Cabernet Sauvignon. New World Cabernet Sauvignon In new world producing countries in Australia, New Zealand and the Americas, Cabernet Sauvignon tends to ripen more fully, producing wines that are much fruiter, more intense and less harsh. Many winemakers will still add other varietals to the blend but these are often not declared on the label. Pure, unblended Cabernet Sauvignon Cabernet Sauvignon has to ripen fully to taste balanced on its own so generally you will only find premium 100% Cabernet Sauvignon from the warmer climates of both the Northern and Southern Hemisphere. Tasting Cabernet Sauvignon and identify its traits The best way to acquaint yourself with Cab Sav to get out the glass, pop the bottle and pour away. Tasting wines side by side will allow you to directly compare what you see, smell and taste. As you taste each of the wines in turn pay particular attention to the how the characteristics change between each of them. The percentage of Cabernet Sauvignon in red blends will vary considerably but generally there is going to be more in those wines from warmer climates where the grapes can ripen more fully. Here's some typical Cab Sav characteristics to get the tasting underway... For an up to 75% Cabernet Sauvignon - Medium colour; Very low sugar / very dry; High acidity/tart; Medium fruit intensity; Mild oak flavour; Medium alcohol/mid-weight; Rough tannic mouthfeel For an over 75% Cabernet Sauvignon - Very dark colour; Low sugar / very dry; High acidity/tart; Medium fruit intensity; Mild oak flavour; Medium alcohol/weight; Softer velvety mouthfeel