With the exception of the wines from Condrieu and Château-Grillet virtually all Rhône Valley whites are made from blends.
In the north, the white wines of Hermitage, Crozes-Hermitage, St-Joseph, and St-Péray are produced from blends of Marsanne and Roussanne. Generally Marsanne is the dominant partner and it lends colour, body and weight to the blend, as well as richly scented fruit. Roussanne, a notoriously low yielder and pernickety to grow, produces intensely aromatic wines which contribute bouquet, delicacy and finesse to the blend.
Until about 15 years ago there was very little interest in southern Rhône whites as it was widely believed that the combination of dull non aromatic grapes and the baking summer heat meant quality wine production was nigh impossible. Since then the quality has improved markedly through the introduction of cool fermentation techniques and increased plantings of northern Rhône white grapes.
The base of many blends is still Grenache Blanc, a widely planted variety producing fresh wines with apple-like fruits, often with hints of aniseed. Ugni Blanc is still found in many blends, as is Clairette though their general lack of character and definition has led to a reduction in plantings. The future for southern Rhône whites appears to lie with Roussanne, Marsanne, and, increasingly, Viognier.