Acids occur naturally in grapes, with acidity in a wine referring to its tartness level. It creates a mouthwatering sensation in the mouth and plays a vital role in providing structure and balance in a wine. Wines without enough acidity are often referred to as "flabby" (water, for example, lacks acidity).

Sweetness in a wine can result from residual sugar (RS) which is the unfermented grape sugars left over in the wine after fermentation has completed, or it can result from the addition of concentrated grape must prior to bottling in the case of sparkling wine production.

Body is a measure of how full and rich a wine tastes -- oily, waxy, viscous, and velvety are terms to describe this. Body is dependent on the grape variety, alcohol level, sweetness, ripeness of fruit, and to some extent how the wine is made.

Tannins are naturally occurring polyphenols found in such plants and food items as grapes skins, seeds, wood, dark chocolate and black tea. In the mouth tannins lend a "grippy" drying feeling and are desireable if balanced with the other elements in a wine (acidity, body, sweetness). If you have trouble drinking a very tannic wine, try it with high-protein foods (meat, tempeh/bean dishes) - the tannin proteins will bind to the food proteins to create a softer effect on the palate.