A varietal wine is simply a wine that uses the name of  the dominant grape from which it was made from, such as a Cabernet Sauvignon or Chardonnay. There are rules in most areas that must be adhered to in order to call a wine a varietal. For example, in the United States at least 75% of the wine must come from the grape variety named on the label, while in Australia  it's 80%. 

Chardonnay

Just as Cabernet Sauvignon has become the most popular high quality red wine grape, Chardonnay has taken the lead for first class white wine grapes. Some argue that the Riesling grape produces the finest  white wine, it's Chardonnay that is being extensively planted throughout the world. In addition to being highly prized, Chardonnay is easy to grow and quite versatile. The wide range of growing soils, as well as the winemakers influence produces a diverse spectrum of Chardonnay wines with varying characteristics. Their flavors can be described as buttery, creamy, nutty, smoky, and steely. The popular fruit descriptors are appley, lemon, melon, and pineapple. Chardonnay is also an important grape in the CHAMPAGNE district of France where it is picked before fully ripe while it still has high acid and understated fruit flavors, which is perfect for making champagne.

Chenin Blanc

Most of the Chenin Blancs produced around the world do not compare to the quality of the top French efforts, particularly those grown in hotter growing areas, which produce grapes that are much more neutral and much less exciting. Wines from cooler regions can be well balanced with delicate, floral characteristics and hints of melon. Because of the grape's high acid content, Chenin Blanc Wines outside of the France are often combined with other wines in order to cut Chenin Blanc's sharpness and enliven the final blend. Chenin Blanc can be picked as a late harvest to make dessert wines. In the U.S. Chenin Blanc is often used to make bulk wine.

Riesling

Riesling is considered to be one of the World's best white wine grapes and produces some of the very best white wines. It's native to Germany, where it's believed to have been cultivated for at least 500 years and possibly for over 2000 years. The Riesling grape's ability to maintain a high acid content as well as high sugar levels is what creates wines with considerable aging potential. Riesling wines are delicate but complex and are characterized by a spicy, fruity flavor (that's sometimes reminiscent to peaches and apricots), a flower-scented bouquet, and long finish. Riesling is vinified  in a variety of styles ranging from dry to very sweet.

Sauvignon Blanc

Sauvignon Blanc is a white wine grape that is widely cultivated in France and the United States. Sauvignon Blanc wines have noticeable acidity and a grassy, herbaceous aroma and flavor. They are crisp flavorful wines made from 100% Sauvignon Blanc grapes and are produced in Loire Valley at Sancerre and Pouilly-Fume. In California, Robert Mondavi gave this Variety a push when it introduced an oaky-styled Sauvignon Blanc Varietal Wine he called Fume Blanc. Now the second best-selling varietal  in California after Chardonnay, Sauvignon Blanc wines are made in a variety of additional styles from those that are crisp and unoaked to Semilon blends. This grape is also known as Blanc Fume, Sauvignon Jaune, and Sauvignon Musque.

Gewuztraminer

Cultivated for over a thousand years, this white wine grape is thought to have originated in the village of Tramin (or Temeno) in Italy's Alto Adige region. Although this variety is not now widely planted in Alto Adige, some of the better Gewurztraminer wines still come from that region. They are highly fragrant, with characteristics of Litchis, roses (or flowers in general), and spice such as cloves and nutmeg. Gewurztraminer wines are available in varying degrees of sweetness from dry to medium sweet or late harvest (dessert wines).