Syrah in the Northern Rhone

The Northern Rhone produces predominantly dry red wines and the sole red grape is Syrah.  Cote Rotie is allowed to blend in up to 20% of the aromatic white Viognier grape whereas in Cornas to the South, the wines must be 100% Syrah.  The allowance for up to 20% Viognier in Cote Rotie is not solely for floral character, but to add body and alcohol to Syrah grown in the northernmost part of the Northern Rhone where Syrah does not always ripen fully.  At Guigal, the famous Cote Brune vineyard is co-planted with 7% Viognier, and is co-picked and co-fermented with the Syrah.  Viognier is a high sugar grape when allowed to ripen to normal maturity, resulting in higher alcohol wines of 13-14%, but when picked at the same time as the late ripening Syrah, it is almost always over-ripe according to Philippe Guigal.   In southernmost Cornas, which enjoys some Mediterranean influences, Syrah always ripens and therefore can be 100% varietal.