Madiran has one-thousand-three-hundred hectares of vineyard, in which the highly tannic [Tannat](/tannat) variety accounts for more than half of all plantings. Other permissible grapes are [Cabernet Sauvignon](/cabernet-sauvignon), [Cabernet Franc](/cabernet-franc) and the less well-known variety, [Fer Servadou](/fer-servadou) (often referred to simply as Fer). The challenge for wine-makers in this part of [France](/country/france), is softening the tannic astringency of the principal grape whilst maintaining the variety’s rustic character. Carefully constructed blends, a meticulously managed maturation process using high-quality oak, and the relatively new technique of micro-oxygenation are all employed to this end. Nevertheless, to be consumed at their best, many of Madiran’s wines will benefit from being laid down for a number of years. Given their high tannin levels, reaching full phenolic ripeness is essential for [Tannat](/tannat) grapes, and the warm, sunny climate of Madiran - particularly in the growing season, makes this possible. The region is also relatively dry, with heavy bursts of precipitation largely limited to late winter and early spring, and the risk of frost damage to the vines is minimal. Free draining, mineral-rich soils of limestone and clay complete the near perfect terroir of the appellation’s viticultural area. Within Madiran AOC, [Tannat](/tannat) is most commonly blended with the Cabernet varieties and more rarely with [Fer](/fer-servadou). By appellation law, the lead grape must comprise at least 60% of any blend, but many wine-makers choose to vinify [Tannat](/tannat) as a mono-varietal, where it delivers big, intensely coloured wines, whose aromatic complexity unravels with age.