Appellation laws permit as many as 14 grape varieties, red and white, to be used in red châteauneuf-du-pape. (Some sources say 13, counting grenache and grenache blanc as one.) The white grapes, interplanted with the red varieties for centuries, were traditionally used to lighten the coarseness of classic châteauneuf—but today, most châteauneufs are blended from only the first four red varieties listed below. The whites are either blended into table wines or, in the case of the nobler ones, vinified on their own. For the record, here are all 14:
• GRENACHE The core of the appellation, accounting for about 80 percent of the grapes grown here. Produces wines with lots of "sweet", alcoholic fruitiness, but can lack definition on its own.
• SYRAH The great northern Rhône Valley grape, here it adds color, concentration, and aroma to the blend.
• MOURVÈDRE One of the Mediterranean's finest red varieties, it's inky and tannic when young, but develops a gamy succulence with age. The backbone of châteauneuf.
• CINSAULT The least interesting of the appellation's four major varieties, and a relatively minor component (at best) in most of the top wines. Shares many of the characteristics of grenache, and can add softness to a blend.
• COUNOISE Valued for its acidity and peppery freshness.
• MUSCARDIN Used as ballast by some producers. Not especially aromatic, but adds weight and savory tannin. Comparatively scarce.
• VACCARÈSE Another rarity, producing wine similar in character to cinsault.
• TERRET NOIR Very scarce, but adds structure and aids acidity.
• GRENACHE BLANC Widely planted, and still the dominant grape in many white châteauneufs, it produces rich, alcoholic wines with lowish levels of acidity.
• ROUSSANNE Arguably the finest white grape in the region and the only one regularly fermented in new oak barrels. Good acidity and an attractively herbaceous aroma when young.
• CLAIRETTE Needs other grapes to give it zip. Ages poorly.
• BOURBOULENC Comparatively rare, but useful, with its fresh natural acidity, for leavening the weight of grenache blanc and clairette.
• PICPOUL Used mainly for its acidity.
• PICARDAN Very rare indeed. Taste it and you can see why: It's neutral and bland.