Wine colour, hue, depth and clarity are attributes assessed when technically judging wine. What does wine colour mean to you? Does it affect your appreciation of the wine you're drinking?
You may not think so, but visual cues do affect your perception of wine. Studies have shown that blindfolding people or serving wine in an opaque black glasses leads to a comparative reduction in ability to distinguish wine style, varietal and age.
If we can agree then that colour is important and enhances the wine tasting experience, let's find out what gives wine its colour. Warning: lots of technical terminology ahead.
Pigments located in the skin of the grapes are what give wine its colour. Most grape varieties don't have any pigment inside the grape (the pulp), so the length of time that winemakers ferment "on the skins" directly impacts the amount and intensity of colour in the resulting wine. That's why rosé wines are pink; even though they are made from red grape varieties, the skin contact with fermenting juice is kept to a minimum, ensuring only a small amount of colour is extracted. The technical name for grape-derived pigments is Anthocyanins. These belong to the group of compounds called Phenolics, which also includes tannins. Each anthocyanin imparts a different 'hue' to the wine, such as violet, ruby, purple and blue. As a wine ages, the hue is dulled and the wine colour turns a more warm, orange hue.
There are a few grape varieties such as Alicante Bousche, Saperavi and Chambourcin, in which the pulp contains pigment as well. These are called Teinturier grapes.
Why do grapes change colour? The stage in the vineyard during which the berries change from hard and green to soft and red or translucent is called Veraison. Grape species undergo this colour change to attract animals who will eat the fruit and disperse the seeds, ensuring survival. White grapes dont have this natural advantage as they actually came about as mutations which were then propogated by humans.
Now, for those of you who want to dive deeper into colour, check out the diagram below which shows where the pigments sit on the red wine colour spectrum:
