As in most of France, viticulture is believed to have been introduced into Aquitania by the Romans. The earliest evidence of sweet wine production, however, dates only to the 17th century. While the English were Bordeaux's main consumer since the Middle Ages, their primary tastes were for red claret. It was the Dutch traders of the 17th century who first developed an interest in white wine. For years they were active in the trade of German wines but production in Germany began to wane in the 17th century as the popularity of Beer increased. The Dutch saw an opportunity for a new production source in Bordeaux and began investing in the planting of white grape varieties. They introduced to the region German white wine making techniques, such as halting fermentation with the use of sulphur in order to maintain residual sugar levels. One of these techniques involved taking a candle (known as a "brimstone candle") with its wick dipped in the sulphur and burned in the barrel that the wine will be fermenting in. This would leave a presence of sulphur in the barrel that the wine would slowly interact with as it was fermenting. Being an anti-microbial agent, sulphur stuns the yeasts that stimulates fermentation, eventually bring it to a halt with high levels of sugars still in the wine. The Dutch began to identify areas that could produce grapes well suited for white wine production and soon honed in on the area of Sauternes. The wine produced from this area was known as vins liquoreux but it is not clear if the Dutch were actively using nobly rotted grapes at this point.
Wine expert Hugh Johnson has suggested that the unappealing thought of drinking wine made from fungus invested grapes may have caused Sauternes producers to keep the use of Botrytis a secret. There are records from the 17th century that by October, Sémillon grapes were known to be infected by rot and vineyard workers had to separate rotted and clean berries but they are incomplete in regards to whether the rotted grapes were used in winemaking. By the 18th century, the practice of using nobly rotted grapes in Tokaji and Germany was well known. It seems that at this point the "unspoken secret" was more widely accepted and the reputation of Sauternes rose to rival those the German and Hungarian dessert wines. By the end of 18th century, the region's reputation for was internationally known: Thomas Jefferson was an avid connoisseur. Jefferson recorded that after tasting a sample of Château d'Yquem while President, George Washington immediately placed an order for 30 dozen bottles.
Like most of the Bordeaux wine region, the Sauternes region has a maritime climate which brings the viticultural hazards of autumn frost, hail and rains that can ruin an entire vintage. The Sauternes region is located 25 miles (40 km) southeast of the city of Bordeaux along the Garonne river and its tributary, the Ciron. The source of the Ciron is a spring which has cooler waters than the Garonne. In the autumn, when the climate is warm and dry, the different temperatures from the two river meet to produce mist that descends upon the vineyards from evening to late morning. This condition promotes the development of the Botrytis cinerea fungus. By mid day, the warm sun will help dissipate the mist and dry the grapes to keep them from developing less favorable rot.
The winemaking of the Sauternes region centers around the development of noble rot. The Botrytis fungus has unique properties that cause the grape to concentrate flavors and sugars while still maintaining the high level of acidity needed to balance the wine and keep it from tasting cloyingly sweet. The botrytis spores are encouraged by the mist and the warmth around the wines. Once they attach themselves to the grape they begin a process of desiccation and they chemically alter components of the grape must. This process increases the concentration of sugars and tartaric acid. During fermentation, this stimulates the production of glycerol which imparts to the resulting wine high levels of viscosity. The fungus also has a dramatic affect on aroma and flavor compounds. This unique element of botrytized wines distinguishes them from other wines that derive their sweetness from fortification, drying or being harvested late. Historically the region would average three vintages a decade producing the conditions needed for the Botrytis cinerea to fully develop. The late 20th century has been more fruitful with an average of six vintages with the needed conditions. The production of Sauternes is very labor-intensive: harvest workers hand-pick individual berries that have been properly infected with the fungus. This may require several trips throughout the vineyard over a couple of weeks. The average yield in Sauternes is between 12-20 hl/ha. The yields of premium producers can be even lower, with Château d'Yquem averaging 9 hl/ha. This is in sharp contrast to the rest of Bordeaux, where the yields are normally around 45 hl/ha. Furthermore, the shriveled and nearly raisin grapes yield only a small amount of juice. It is not uncommon for an entire grapevine to produce only enough juice to make a single glass of wine. This contributes to a very small production, with most producers averaging 1,000-7,000 cases a year, and is the primary reason for the high costs associated with Sauternes.
The influence with the most impact on the resulting wine takes place in the vineyard, where the character and complexity of the botrytis-infected grape is set prior to winemaking. At the winery, the grapes are treated as gently as possible during pressing. In the 1980s, the controversial and expensive pre-pressing process of cryoextraction was developed. During this process, the grapes are placed in a special cooling compartment where they are chilled for 20 hours. Grapes that are less ripe have a higher water concentration then riper, sugar-saturated grapes. During this cooling process, the water is frozen, allowing the pressing process to maximize the amount of concentrated juice that is produced. Traditionalists have contended that cryoextraction is an excuse for "lazy harvesting" and that it adds to the expense of Sauternes without necessarily adding to the quality. However its use has been steadily rising, especially in poor vintage years. Fermentation frequently takes place in oak barrels with the house style dictating the amount of new oak used each vintage. The fermentation process will naturally stop at a level of around 14% alcohol, though the use of specially selected cultured yeasts can sometimes take it higher. In poor vintages, chaptalization may also be used to increase alcohol and body. Some winemakers may choose to stop fermentation prematurely by the use of sulfur dioxide, in order to maintain higher levels of residual sugar. After fermentation the wine will be aged from 18-36 months in oak prior to release.
Sauternes are characterized by the balance of sweetness with the zest of acidity. Some common flavor notes include apricots, honey and peaches. The finish can resonate on the palate for several minutes. Sauternes are some of longest-lived wines, with premium examples from exceptional vintages properly kept having the potential to age well even beyond 100 years. Sauternes typically starts out with a golden, yellow color that becomes progressively darker as it ages. Some wine experts, like Ed McCarthy and Master of Wine Mary Ewing-Mulligan, believe that only once the wine reaches the color of an old copper coin has it started to develop its more complex and mature flavors.
Several Sauternes are sold in half bottles of 375 ml, though larger bottles are also produced. The wines are typically served chilled between 52-53°F (11°C) though wines older than 15 years are often served a few degrees warmer. Sauternes can be paired with a variety of foods. Foie gras is a classic match.