Tannat is a red wine grape varietal, historically grown at the foothills of the Pyrenees Mountains in south-western France in the Madiran AOP. Having been grown in that region since the 17th and 18th centuries. It is also grown in Uruguay, Argentina, Australia, Brazil, Peru, and in Italy's Puglia region where it is used as a blending varietal.
Tannat wines produced in Uruguay are usually quite different in character from Madiran expressions - typically being lighter in body and lower in tannins. It is also used to make Armagnac and full-bodied rosé wine. In France, efforts to solve the harsh tannin nature of the grape varietal, lead to research and the development of the winemaking technique now known as 'micro-oxygenation' - by the Madiran winemaker Patrick Ducournau.


Tannat - as mentioned, is notable for its very high levels of natural tannins and is often blended with lighter style red varietals - along with Cabernet Sauvignon and Cabernet Franc to soften their astringency (grown in cool conditions) and to give them more balance. A French Tannat wine is characterised by its firm, tannin structure with smoky-oak and plum aromas, a dried spice finish and the ability to age well.
French Kings accepted Madiran wines as payment for taxes. Madiran appellation laws mandate that Tannat be blended with Cabernet Sauvignon or Cabernet Franc, but producers have recently begun receiving notable press for their 100% Tannat Madiran wines.
Tannat continues to be grown in the Basque country, most notably in the small appellation of Irouleguy, on the Spanish border. In 1870, Basque immigrants took the grape to Uruguay, where it has adapted extremely well. Today it is often blended with Pinot Noir and Merlot and is made in a variety of styles including those reminiscent of Port and even Beaujolais.

From Uruguay the vine spread to Argentina and from there flying winemakers promoted the grape's growth in California at the end of the 20th century. It has since become the national red grape varietal of Uruguay, accounting for approximately one third of all wine produced in the country; more Tannat is grown in Uruguay than in the varietal's native France.