Gustatory analysis begins in the mouth and involves the interpretation of three types of sensation: taste, tactile sensation and aroma.
Taste
Tastes are mainly detected by the gustatory cells of the papillae located on the tongue. These papillae are formed by hundreds of cells known as taste buds which react with substances in the mouth sending electrical impulses via a series of neurons to parts of the brain responsible for registering taste sensations.
Taste in the strict sense is limited to the recognition of four flavours: sweet, acid, salty and bitter. We are able to distinguish these flavours one from the other because there is a time lapse between contact with the stimulus and the perception of it, which is different for each of the primary tastes. This means that we always recognize the four basic Flavours in the same sequence, first sweet followed by acid, salty and bitter. Some tastes last longer than others, and this persistence is an important factor in evaluating a wine. Each of the primary tastes is perceived mainly on a different area of the tongue.
Sweetness: is detected mainly at the tip of the tongue by the fungi form papillae sensitive to sugars (the sugar content of wine varies from 0 to 150 g/1), alcohol and glycerine. The sensation of sweetness has a time lag of about one second and persistence of up to 10 seconds.
Acidity: this is detected mainly along the sides of the tongue by foliate papillae sensitive to the different types of acids in wine. The six main types and their tastes are:

	tartaric (hardness)
	malic (sour apples)
	citric (sharp, lemony)
	succinic (a salty bitterness that causes salivation)
	lactic (milky tartness)
	acetic (acrid, vinegary).

Tartaric, malic and citric acid are natural components of grape juice. Succinic, lactic and acetic acid on the other hand are produced by fermentation. Total acidity in wine varies from 4-10 g/1. The sensation of acidity is second in the taste sequence with a time lag of about 2 seconds and a persistence of up to 12 seconds.
Saltiness: is detected mainly at the upper front part of the tongue by foliate papillae sensitive to salts, which derive from minerals or organic acids, present in quantities varying between 2 and 3 g/l. The sensation of saltiness has a time lag of about 2 seconds, but its persistence is of little relevance since the traces of salt in wine serve mainly to highlight sweet and acidic flavours.
Bitterness: this is detected mainly at the back of the tongue by circumvallated papillae sensitive to phenolic substances including quinines, and ethyl acetate. The bitter sensation is the last to be perceived with a time lag of about 3 seconds and persistence of up to 15 seconds. This lingering effect accounts for the bitter aftertaste described in certain wines.

Tactile Sensations
Practicality all of the oral cavity has some sense of touch, but the parts most sensitive to the "tactile impressions" of wine are the upper, centre part of the tongue and the soft areas of the palate, the pharynx, the larynx and the gums. The centre of the tongue contains fluiform papillae that feel rather than taste and transmit signals to the brain. "Chewing" on a mouthful of wine is a technique which helps to accentuate the sensations of texture, temperature, astringency, body and the prickle from carbon dioxide in sparkling wines.
Texture: this refers to the fabric of a wine, the way it feels in the moilth, often described by general impressions of touch. It includes for example the sensation of smooth, rich viscosity which is typical of certain dessert wines and is caused by the combination of sugar~ glycerine and alcohol.
Astringency: is the dry sensation caused mainly by the tannins present in young red wines. The ageing process reduces astringency, and as a. result it is much less evident in mature and older wines. It should not be confused with the bitter taste which on the con trary increases with the age of a wine.
Temperature: refers in this context to the sensation of warmth created by ethyl alcohol, which increases with the wine's strength.
Body: is a term which expresses the sense of weight of a wine in the mouth. The impression of full-body is almost like that of chewing on something solid. It is created mainly by the dry extract (i.e. the components of the wine which are left after the liquids have been evaporated) and alcohol.
Prickle: a prickly sensation is caused by the presence of carbon dioxide which accentuates the acidity of white wines and the astringency of reds, while reducing the impact of sweetness.
Aromatic Taste Sensations
The basic tastes of wine in the mouth are complemented by the aromatic
qualities sensed by the olfactory system by way of the nasal passage at the back of the mouth. These aromas are conveyed to the olfactory bulb as the taster inhales through the mouth and exhales through the nose.
This effect is influenced by several factors. The temperature in the mouth, which is warmer than that of the air, causes a slight evaporation of the wine which releases volatile scent molecules. Saliva, which is secreted liberally during tasting, chemically modifies certain substances in wine through a process known as hydrolisis which makes them odorous. The intensity of the sensation can be increased by pressing the tongue against the roof of the mouth in a movement which compresses the wine, again liberating odorous particles.