Saccharomyces cerevisiae
One of the main yeast species found in grapes and wines throughout the world. Most of the yeast strains used to ferment white wines are of this species.

Sauvignon Blanc
A popular white varietal in Europe, California and Australia. Sometimes called Fume Blanc in California, can be made into botritised dessert wines.

Secondary fermentation
A fermentation that takes place after the primary fermentation. Both malolactic fermentation and the second alcoholic fermentation in sparkling wines are secondary fermentations.

Sediment
The residue of solids in a bottle of red wine that forms as the wine is matured.

Semillon
A lesser known white grape often blended with Sauvignon Blanc, especially in the production of the sweet wines of Sauternes, France.

Sensory evaluation
The assessment of wine based on sight, smell, taste and touch.

Serious
A description used for a wine that is of high quality.

Settling
The precipitation of the solid matter in wine.

Sherry
A fortified wine from Jerez de la Frontera, Spain, made by a controlled oxidation method, produced in many different styles, from sweet Cream sherry to very dry Fino sherry.

Shiraz
The Australian name for Syrah, a red grape variety.

Silky
Displaying a supple, smooth texture.

Single-vineyard wine
Wine made from grapes grown in one specific vineyard block, and bottled without being blended with wine from any other vineyard.

Skin contact
The time in the winemaking process when the juice of the grapes are in contact with the skins, extracting color, tannin and other substances.

Slightly sweet
Containing a barely perceptible amount of residual sugar.

Smoky
Displaying aromas that suggest smoke or smoked wood.

Smooth
A description for wine whose texture is not astringent.

Soft
Description for a wine whose alcohol and sugar dominate the tannin and acidity, resulting in a wine without roughness or hardness.

Solera System
A system used in the creation of Spanish sherry to carefully blend new and older vintages of wine to achieve a consistent style.

Sommelier
A wine steward.

Sour
The acid taste of wines that are made from unripe grapes.

Sparkling
Wine with an effervescence caused by a secondary alcoholic fermentation that leaves carbon dioxide trapped in the bottle.

Spicy
A term used to describe wine that displays aromas and flavors reminiscent of aromatic spices.

Spirits
In wine, the distilled alcohol used to make fortified wines.

Stabilization
The process of removing unwanted substances before bottling so they won't cause haziness or crystal formation in the finished wine.

Starter
A batch of active yeast that is used to begin fermentation.

Stemmer
A machine that separates the grapes from their stems, generally combined with a crusher and known as a "stemmer-crusher."

Stemmy
A term for wines that exhibit dry, woody tannins.

Stems
The woody part of a grape bunch that is high in tannin. Stems are removed before fermentation using a stemmer.

Still wines
Any wine without effervescence.

Stony
Displaying flavors or aromas that suggest stones or wet stones.

Structural components
A wine's alcohol, acid, tannin and sugar.

Structure
The impression conveyed by a wine's structural components.

Style
The characteristic combination of components - alcohol, acid, tannin and sugar - associated with the wines of a region, a winery or a particular winemaker.

Sulfer Dioxide
The compound used to inhibit the growth of unwanted microorganisms and to stop browning in wine.

Supple
A term meaning fluid in texture in the mouth, without any sharpness or roughness.

Sur lie
A French term meaning, literally, "on the lees." Generally refers to the aging of wines on the deposit of dead yeast that forms after primary fermentation. Sur lie aging imparts a toasty quality and enhances complexity.

Sweet
The taste of a wine with perceptible residual sugar, and the description of any dessert wine.

Sweetness
The impression of sugar in a wine, either from residual sugar or from alcoholic content.

Syrah
A distinguished red varietal made famous in the Rhone Valley, now grown in California and Australia, where is it known as Shiraz.