While it is often said that "taste is subjective", there are wine properties quantifiable taste characteristics (like bitter, sweet, salty or sour) that can be perceived and measured as low, moderate or high--such as measuring the sweetness of honey or the saltiness of oysters. Flavors, such as butterscotch, char and strawberry, are more personal and can't be quantifiable. Flavors are either perceived to be present or not.
The perception of flavors is linked to our sense of smell, while tastes come from the sensory glands of the taste buds. Though individual sensitivity to the different taste "senses" can vary, wine experts will often recommendpairings based on these more objective measurements rather than the more subjective concept of "flavors".
In wine properties there are three basic tastes-bitter, sweet and sour. These three tastes can each be identified with a primary component of the wine-tannins (bitter), residual sugar (sweet) and acidity (sour). A fourth component, alcohol, is identified in wine tasting with a perception of "heat" or hotness in the back of the mouth and is the primary factor influencing the body of the wine. The residual heat of the alcohol can be considered in food pairing with some ingredients minimizing the heat of the wine while some will accentuate it.
The acidity of salad dressing and tomatoes can cancel some of the tartness in a Beaujolais wine, allowing the fruit to be more noticeable. Acidity is a dominant player in any food and wine pairing due to the pronounced and complex ways that it can heighten the perception of flavors. In wine tasting, acidity is perceived by a mouth watering response by the salivary glands. This mouth watering can also serve to stimulate the appetite. In wine there are three main acids that have their own associated flavors-malic (green apples), lactic (milky) and tartaric (bitter). In dishes that are fatty, oily, rich or salty, acidity in wine can "cut" (or standout and contrast) through the heaviness and be a refreshing change of pace on the palate. In cooking, acidity is often used in similar fashions such as a lemon wedges with a briny seafood dish such as oysters. The acidity of the lemon juices can make the oysters seem less briny. A wine that is less tart than the dish it is served with will taste thin and weak. A wine that comes across as "too tart" on its own maybe soften when paired when an acidic and tart dish. The complementing "tartness" of the food and wine cancels each other out and allows the other components (fruit of the wine, other flavors of the food) to be more noticeable.
The sweetness of wine properties is determined by the amount of residual sugar left in the wine after the fermentation process. Wines can be bone dry (with the sugars fully fermented into alcohol), off-dry (with a hint of sweetness), semi-dry (medium-sweet) and dessert level sweetness (such as the high sugar content in Sauternes and Tokays). Sweet wines often need to be sweeter than the dish they are served with. Vintage brut champagne paired with sweet, wedding cake can make the wine taste tart and weak while the cake will have off flavors. In food pairings, sweetness balances spice and heat. It can serve as a contrast to the heat and alleviate some of the burning sensation caused by peppers and spicy Asian cuisine. It can accentuate the mild sweetness in some foods and can also contrast with salt such as the European custom of pairing salty Stilton cheese with a sweet Port. Sweetness in a wine can balance tartness in food, especially if the food has some sweetness (such as dishes with sweet & sour sauces).
The proteins and fats in cheese can soften the perception of tannins in wine, making a wine seem less bitter and more fruity. The bitterness associated with wine is usually derived from a wine's tannins. Tannins add a gritty texture and chalky, astringent taste. It can enhance the perception of "body" or weight in the wine. Tannins are normally derived from the skins and stems of the grapes themselves (leeched out during the maceration process) or from contact with oak during barrel aging. Tannins react to proteins. When paired with dishes that are high in proteins and fats (such as red meat and hard cheeses), the tannins will bind to the proteins and come across as softer. In the absence of protein from the food, such as some vegetarian dishes, the tannins will react with the proteins on the tongue and sides of the mouth--accentuating the bitterness and having a drying effect on the palate. Various cooking methods, such as grilling and blackening can add a bitter "char" component to the dish that will allow it to play well with a tannic wine. While fish oils can make tannic wines taste metallic or off. Bitter tannic wines like Barolo and Cabernet Sauvignon can overwhelm a lot of foods but can be soften by fatty foods with a lot of proteins such as hard cheeses or meats. The dry tannins also serve as a cleansing agent on the palate by binding to the grease and oils left over in the mouth. Spicy and sweet foods can accentuate the dry, bitterness of tannins and make the wine properties seem to have off flavors.
Alcohol is the primary factor in dictating a wine's weight & body. Typically the higher the alcohol level, the more weight the wine Property has. An increase in alcohol content will increase the perception of density and texture. In food and wine pairing, salt and spicy heat will accentuate the alcohol and the perception of "heat" or hotness in the mouth. Conversely, the alcohol can also magnify the heat of spicy food making a highly alcoholic wine paired with a very spicy dish one that will generate a lot of heat for the taster.