The colour of a wine reveals a great deal about a number of aspects of a wine, including:
- fermentation technique
- sugar levels
- keeping ability
The viscosity of a dry wine is primarily due to ethanol, although other components do have an effect.
- Low ethanol content less than 10% the wines are thin.
- Wines with an ethanol content greater than 12% are said to be full bodied.
The Glycerol content does not impact upon the body of a wine. The viscosity of a wine can be judged by the tears in the wine that cling to the side of the glass when swirling it around. This observation will indicate the degree of body weight that will be experienced as a taste sensation on the palate.
Brilliance or clarity is important visual concentration in a wine and is the observation of the degree or absence of suspended material.
- cloudy - due to faults treatment on bacterial spoilage - this can also lead to off odours experienced on the nose.
- hazy - presence of certain bacteria or protein haze.
- floating white film
- May indicate growth of aerobic macro organisms which could lead to
(i) oxidation if they are yeast film
(ii) vinegariness if caused by bacteria
- milky cloudiness - May be due to excess iron or copper - protein reaction
- cloudiness with chrystaline deposit- Can be caused by excess potassium acid tartrate or calcium
- sediment - Tannin deposit due to bottle age
- Purity or saturation of colour
The human eye is most sensitive to differences in the tint of colour in the green region of the spectrum. The apparent colour can be modified by the background light, and thus, it is important to view colour under hospital grade lights. These can come in fluorescent tubes that give the maximum expression to tint and saturation of colour.