Cabernet Sauvignon is one of the most popular and widely planted red grape varietals in the world. Part of its attraction is that it has a distinctive and very recognizable taste no matter where it is grown—which is perhaps why today we can find it in just about any wine growing region which is reasonably warm.
According to Jose Vouillamoz, a botanist specializing in grape DNA, Cabernet Sauvignon is actually a relatively young varietal, only appearing in the 18th Century as the result of a “natural” crossing of Sauvignon Blanc and Cabernet Franc in one of the many co-planted Bordeaux vineyards. Part of its immediate success came about because it’s a very obliging grape to grow: fairly disease resistant, and easy to vinify.  Baron Hector de Brane of Château Mouton and Armand d'Armailhacq, of Château Armailhac (later purchased by Baron Philippe de Rothschild), are credited with the promotion and promulgation of the variety in the Médoc, where it quickly became the most widely planted variety.
King Cab the Colonizer
In the last 50 years, Cabernet Sauvignon has been viewed as an aristocratic and magnificent grape variety capable of producing fruit-forward, powerful young drinking wines as well as complex and sublime long lived wines. Moreover, Cabernet Sauvignon has a distinctive and very memorable flavor profile, making it a consumer favorite. For many red wine drinkers, the wines and brands became increasingly, consistently recognizable. 
As its commercial success increased, so did the number of regions and countries where Cabernet Sauvignon was planted. Its genius ability to modernize and spice up most red blends added to its rampant colonization in vineyards all over the world.  
From winery to winery, the high concentration of phenolics in the varietal allows for extended maceration times, resulting in deeply colored and tannic wines. Furthermore, Cabernet Sauvignon’s startling affinity with new oak creates wines where black currant flavors seamlessly blend with vanilla and sweet spicy notes. The strong tannic structure, deep color and fruit-forward characteristic also are the reason why Cabernet Sauvignon tends to hijack most blends it has been added to. Its powerful personality seems to add the exact amount of “trendiness” to a traditional blend, giving it a broader appeal for most red wine drinkers.

King Cab, the brand, thus became the key that would open doors in restaurants and stores in the US, the UK, Asia and, eventually, the rest of the world.

Wine basket image via shutterstock
Blend or Single Varietal?

Whilst it’s true that Cabernet Sauvignon is relatively easy to grow in most wine regions which are warm enough, and will produce a wine that is easily recognizable, there are very few regions in the world where Cabernet Sauvignon by itself is better than the blend. Even in its native Bordeaux, Cabernet Sauvignon is rarely bottled as a single varietal. Instead it’s generally blended with the much fatter Merlot and perfumed Cabernet Franc. In Spain, Cabernet Sauvignon is often blended with Tempranillo, especially in the regions of Navarra and Cataluña; in Tuscany, it is often blended with Sangiovese, though some super Tuscan’s are single Cabernet Sauvignon varietal wines.
A lot of excellent single varietal examples come from the New World. The Napa and Sonoma Valleys are two regions in California which are well known for producing some excellent Cabernet Sauvignons. There is quite a big difference between hillside and valley floor wines: the hillside wines tend to have smaller berries and lower yields, resulting in more intense and austere wines, which are slower to mature and more elegant than the more opulent and fruit-forward valley floor wines.
Australia is another region were Cabernet Sauvignon fares very well as a single varietal, especially in Coonawarra and Margaret River. Both regions are coastal and a little cooler than more inland wine growing regions, and Coonawarra’s Terra Rosso soils tend to bring out the fine structure and more minty fruit flavors in Coonawarra’s Cabs. The wines from Margaret River are tightly structured, with a lot of black fruit flavors and kitchen herb notes.

Some of Chile’s most renowned Cabernets come from the Maipo Alta region, which is a little cooler; here Cabernet Sauvignon produces elegant wines characterized by intense black currant flavors with a hint of eucalyptus. In the warmer regions, it gives richer and fast developing wines with a softer tannic structure, sweet fruit and less acidity. 
Argentina has been growing Cabernet Sauvignon in the Mendoza valley close to the Andes for over 100 years, and some of the finest examples again come from the cooler sites. Wine producer and journalist Gabriel Dvoskin pointed out that Argentina is the only region in the world to grow a "continental" style of Cabernet Sauvignon and told me that there are currently a lot of experiments going on to define the specific characteristics associated with this style. This is may be why often Argentinian Cabernet Sauvignon is typically blended with Malbec. In general, Argentinian Cabs are quite exuberant and high in alcohol, and young drinking wines show typically a lot of bold stewed fruit. 
South African Cabernets often show a lot of ripe sweet fruit as well as some herbaceous and minty notes, whilst in New Zealand herbaceous characters and cassis flavors tend to be more dominant. Although some single varietal South African Cabernet Sauvignons are excellent (especially from the Stellenbosch area), the Bordeaux blends remain popular. In New Zealand, Cabernet Sauvignon is generally grown in the warmer region of Hawkes Bay, but even here it struggles to completely ripen. That is why it often forms the backbone of the excellent Hawkes Bay Bordeaux Blends.
Tasting Notes:
(60% Cabernet Sauvignon, 20% Merlot, 10% Cabernet Franc, 10% Petit Verdot)
Ruby in color with a nose of red berries, a hint of rosemary and shaved pencil cuttings. An elegant and well developed wine, with a good acidity and velvety tannic structure; juicy on the palate with a lot of red berry flavors and a hint of fresh mint in the smoky finish.
2007 Shafer Hillside Select 2007 Napa Valley
(100% Cabernet Sauvignon) 
Deep ruby in color, with lots of red fruit notes and a hint of eucalyptus on the nose. Very well balanced with a fine grained, almost silky tannic structure; good mouth feel and layers of red and black fruit (blackberry, blackcurrant, dark cherry) flavors, some dried kitchen herbs and a little cigar smoke and cocoa in the long finish.
Dark ruby in color, with a nose of very ripe almost stewed dark fruit as well as a few mineral notes. An elegant, well balanced wine with smooth velvet integrated tannin, a good mouth feel and lovely freshness. Flavors of dark plum, jammy mulberry and blackberry, some sweet spice (cloves, allspice) in the long finish.
Deep ruby in color, tons of blackcurrants and cherries and a hint of  kitchen herbs and dried tobacco on the nose; a very well balanced wine with great freshness, fine grained tannins and elegant texture and flavors of dark berries, black cherry and a hint of dried sage, sweet liquorice and cigar smoke in the lingering finish.
Dark ruby in color, with a nose of black currants, a hint of vanilla and eucalyptus. Full bodied, bold wine with fine grained tannin and a lifted freshness; lots of flavors of cassis and blackberry, a hint of eucalyptus and a spicy, peppery finish.
Dark ruby in color, with an intense nose of blackberries and a touch of cocoa. A bold concentrated wine, with a powerful mouth feel, good tannic structure and a lovely freshness; it shows layers of ripe black fruit (blackberry, blueberry and blackcurrant) , a touch of dark chocolate and some kitchen herbs in the persistent finish.
2008 Kaiken Cabernet Sauvignon Ultra Mendoza, Argentina
(90% Cabernet Sauvignon, 10% Malbec)
Deep ruby in color with a black berry and cherry and a hint of sweet spice on the nose. A full bodied yet elegant wine with plenty of tannin and an almost silky mouth feel, lots of blackcurrant and cherry notes, and a little sweet spice and cigar smoke in the lingering finish.
Deep ruby in color, with a nose of red berries, a hint of cassis and some cedar. An elegant wine, with a firm tannic structure and good acidity; pretty fruit-forward on the palate with an explosion of red and black berries in the mid palate and a little cocoa and dried herbs in the smoky finish.