Viognier is a white wine grape variety. It is the only permitted grape for the French wine Condrieu in the Rhône Valley. Outside of the Rhône, Viognier can be found in regions of North and South America as well as Australia, New Zealand, the Cape Winelands in South Africa and Israel. In some wine regions, the variety is co-fermented with the red wine grape Syrah where it can contribute to the colour and bouquet of the wine.

Like Chardonnay, Viognier has the potential to produce full-bodied wines with a lush, soft character. In contrast to Chardonnay, the Viognier varietal has more natural aromatics that include notes of peach, pears, violets and minerality. However, these aromatic notes can be easily destroyed by too much exposure to oxygen which makes barrel fermentation a winemaking technique that requires a high level of skill on the part of any winemaker working with this variety. The potential quality of Viognier is also highly dependent on viticultural practices and climate with the grape requiring a long, warm growing season in order to fully ripen but not a climate that is so hot that the grape develops high levels of sugars and potential alcohol before its aromatic notes can develop. The grape is naturally a low yielding variety which can make it a less economically viable planting for some vineyards.

Viognier wines are well known for their floral aromas, and terpenes, which are also found in Muscat and Riesling wines. There are also many other powerful flower and fruit aromas which can be perceived in these wines depending on where they were grown, the weather conditions and how old the vines were. Although some of these wines, especially those from old vines and the late-harvest wines, are suitable for aging, most are intended to be consumed young. Viogniers more than three years old tend to lose many of the floral aromas that make this wine unique. Aging these wines will often yield a very crisp drinking wine which is almost completely flat in the nose. The colour and the aroma of the wine suggest a sweet wine but Viognier wines are predominantly dry, although sweet late-harvest dessert wines have been made. It is a grape with low acidity; it is sometimes used to soften wines made predominantly with the red Syrah grape. In addition to its softening qualities the grape also adds a colour-stabilizing agent and enhanced perfume to the red wine. In the Rhone region, the grapes normally are not affected by the fungus Botrytis cinerea though botrytized Viognier is not unheard of.

In winemaking, the grapes are often harvested early in the morning to produce the clearest juice possible. Some winemakers will allow contact with the skins. The skin of Viognier is high in phenols - compounds that can leave an astringent component to the wine if juice is left in contact with the skins for too long. Sometimes the wine is put through malolactic fermentation to give the wine more weight and to decrease acidity. In New World Viognier, the lees may be stirred in a process called batonnage in order to increase the smooth texture of the wine. The wine is then left on the lees till bottling in a manner similar to sparkling wine production.

In the creation of the dessert style Viognier, the grapes are often picked in late October or early November in the Northern Hemisphere. A common harvest technique used in the Condrieu is known as à l'assiette where a plate is held underneath a Viognier vine that is then shaken to allow the overripe grapes to drop onto the plate. Fermentation is then stopped early through the use of sulphur dioxide to allow the wine to retain a high level of residual sugar. The wine is then chilled and put through sterile filtration to ensure that the wine is stable and will not start fermenting again in the bottle.

Depending on the winemaking style the grape can often hit its peak at one-two years of age, though some can stay at high levels of quality up to ten years. Typically Condrieu wines are the Viogniers most often meant to be drunk young while Californian and Australian wines can handle age a little bit better.