Synergy is the goal of blended wines, though many consumers focus on single grapes like Cabernet Sauvignon, Chardonnay, Pinot Noir and Sauvignon Blanc. Indeed, an understanding of how an individual grape tastes can build a foundation of knowledge. However, many of the world\u2019s greatest wines are based on blends. Wines from Bordeaux, Southern Rh\u00f4ne, Champagne, Chianti and the Douro Valley are benchmarks for the art of grape blends.\r\n\r\n\r\nBordeaux\r\nBordeaux\u2019s identity is predicated on blends. Both the white and red wines, as well as the sweet Sauternes, use two or more grapes. The classic varieties in a Bordeaux red blend are Cabernet Sauvignon, Merlot, Cabernet Franc, Petit Verdot and Malbec. Carmen\u00e8re, a mostly forgotten grape that\u2019s emigrated to Chile, makes a rare appearance.\r\n\r\nThe composition of a Bordeaux wine blend, however, depends on which side of the Gironde estuary that the grapes grow. On the left bank, in the M\u00e9doc and Graves regions, red blends are Cabernet Sauvignon dominant. On the right bank, in the Libournais region, they\u2019re comprised mostly of Merlot, filled out with Cabernet Franc.\r\n\r\nWhite blend wines are mostly based on Sauvignon Blanc, S\u00e9millon and Muscadelle, with Sauvignon Gris, Colombard, Ugni Blanc and Merlot Blanc occasionally used. These varieties also comprise the sweet, botrytized wines from Sauternes and Barsac.\r\n\r\nHistorically, grapes were planted and blended for many reasons. If one variety failed, the grower could rely on others. Also, the grapes ripen at different times, which reduces logistical challenges at harvest.\r\n\r\nThird, and most important to the production of fine wine, different grapes bring their own flavor, aroma, acid and tannin qualities, which enhances complexity. That balance makes an austere, structured and tannic Cabernet Sauvignon combined with a ripe, soft and velvety Merlot a magical experience.\r\n\r\n\r\nSouthern Rh\u00f4ne\r\n\u201cG-S-M\u201d wine is an abbreviation for a blend of the Grenache, Syrah and Mourv\u00e8dre grapes. They can be found in many of the world\u2019s warm-climate wine regions. But the model for this trio originated in Southern France, where it was made famous in the Rh\u00f4ne Valley. Of course, the French have had hundreds of years to perfect their recipes. So, what makes these grapes combine so beautifully?\r\n\r\nIn fact, up to 18 different grapes are allowed in wines from the appellations of C\u00f4tes du Rh\u00f4ne and up to 13 in Ch\u00e2teauneuf-du-Pape. Only a few producers work with most or all of them. The rest focus on three that truly define the style.\r\n\r\nGrenache often comprises the largest percentage of a G-S-M wine blend. It\u2019s moderate in color and tannin, but also high in alcohol. It offers candied raspberry and strawberry flavors peppered with spice. Syrah brings acidity, structure and savory, smoky, meaty notes. Mourv\u00e8dre supplies a deep hue, tannins and a hint of a floral character.\r\n\r\nRh\u00f4ne Valley whites also have a legacy based on blending. One French grape, Viognier, has seen its fortunes rise in America. But the only Rh\u00f4ne Valley single-varietal expressions of the grape are found in the Northern Rh\u00f4ne. Otherwise, blends rule. The main grapes used are Viognier, Marsanne, Roussanne, Grenache Blanc, Clairette and Bourboulenc, with smaller amounts of Picpoul Blanc, Picpoul Gris and Picardin. Marsanne and Roussanne are frequent companions, while in Ch\u00e2teauneuf-du-Pape, Grenache Blanc typically brings heft, flavor and freshness.\r\n\r\n\r\nChampagne\r\nNo discussion of blends would be complete without France\u2019s famous sparkling wine. Champagne employs the classic trio of Pinot Noir, Chardonnay and Pinot Meunier, though the first two do the heavy lifting. Seven grapes are permitted by the Champagne Appellation d\u2019Origine Contr\u00f4l\u00e9e (AOC). The remaining four are Pinot Gris, Pinot Blanc, Petit Meslier and Arbane.\r\n\r\nPinot Noir contributes structure plus berry fruit and perfume to the blend, while Chardonnay brings tension and elegance that sets the wine up for extended lees and bottle aging. Pinot Meunier gives body, roundness and fruit.\r\n\r\nThough the grapes prove able partners, their selection for Champagne production rested initially on their likelihood to ripen. Centuries ago, vineyards in this cool, continental climate of Northern France were barely viable. While Pinot Meunier has fervent defenders that champion its ability to make beautiful, stand-alone wines, its inclusion in Champagne rested on pragmatism. It buds, flowers and ripens earlier than the other two grapes, which gave growers an insurance policy against poor weather.\r\n\r\nBut Champagne is a blend of not just grapes, but of vintages and crus. Due to the extreme variability of Champagne\u2019s climate, each harvest can produce dramatically different wines. To blend across seasons allows producers to mingle fresher wines from one year with riper offerings. Terroir also plays out across the various Champagne crus, which allows houses to combine structured, linear wines from one site with softer, fruitier wines from another.\r\n\r\n\r\nChianti and Chianti Classico, Italy\r\nFew wine lovers think of Chianti as a blend. Most imagine Sangiovese as the hero of the story. Yet, this wine from Tuscany long required a bevy of local grapes.\r\n\r\nIn 1716, Grand Duke Cosimo III de\u2019Medici demarcated the first Chianti wine zone. After two centuries of growth and the creation of the Chianti Denominazione di Origine Controllata (DOC), de\u2019Medici\u2019s original area became Chianti Classico, with its own appellation in 1967.\r\n\r\nThe larger, separate appellation of Chianti Denominazione di Origine Controllata e Garantita (DOCG) has seven subzones that include Chianti Rufina and Chianti Colli Senesi. Each subzone has slightly different grape requirements, but the gist is that at its broadest, Chianti DOCG requires a minimum of 70% Sangiovese with a maximum of 10% white grapes Malvasia and Trebbiano. Native red grapes Canaiolo Nero and Colorino, as well as international varieties Cabernet Sauvignon, Merlot and Syrah, are allowed. These add fruit, tannin or softness to the final blend.\r\n\r\nHowever, Chianti Classico DOCG, banned white grapes in 2006. Today, Chianti Classico must contain at least 80% Sangiovese, with a maximum of 20% of other red grapes Colorino, Canaiolo Nero, Cabernet Sauvignon or Merlot.\r\n\r\nEven more of a curiosity, 100% Sangiovese wines were once banned. So, by law, historically Chianti was a blend.\r\n\r\nAs viticulture and winemaking modernized, Sangiovese proved worthy as a standalone variety. Its tart red cherry flavors, bright acidity and sandy tannins make it food-friendly and capable of moderate aging.\r\n\r\nCanaiolo played second fiddle in blends for its fruit and ability to soften Sangiovese\u2019s tannins, similar to Merlot role alongside Cabernet. Colorino added structure and color, while its resistance to rot in the vineyard made it appealing. Though Canaiolo and Colorino fell out of favor, a handful of winemakers who sought to pay homage to Chianti\u2019s history have begun using it again.\r\n\r\n\r\nPort and Douro Valley Reds\r\nWine has been made in Portugal\u2019s Douro Valley for thousands of years. For as long as vineyards have existed on the exquisite terraces that hug the curves of the Douro River, wines have been based on blends.\r\n\r\nWhile Port wine is the most famous product of the region, many producers have turned to dry red wine blends that appeal to a changing market.\r\n\r\nA multitude of indigenous grapes comprise classic red Port and dry red table wines. The most common are Touriga Nacional, Touriga Franca, Tinta Roriz, Tinta Barroca, Tinto C\u00e3o and Tinta Amarela. White grapes used in white Port and dry white table wines include Gouveio, Rabigato, Viosinho, Malvasia Fina, Donzelinho Branco and Cerceal.\r\n\r\nTouriga Nacional contributes fruit and floral aromatics, herbal notes and full body that offers aging potential. Touriga Franca sports aromas of roses and violets with velvety tannins, while Tinta Roriz, the same grape as Spanish Tempranillo, brings red fruits and spice.\r\n\r\nThis balanced combination results in perfumed, spicy, rich and fruity Ports often with notes of red and black fruit, violets, cinnamon, clove, caramel and chocolate. They are masterpieces in blending and winemaking technique.