Wine has many beautiful traits. The smell (the nose) and the taste (the palate) are probably the most feverishly debated characteristics amongst wine drinkers after the cork has been drawn (or screwcap twisted off, as the case may be).
But what about a wine’s colour? As much as the colour of a wine perhaps isn’t as important as how it tastes or smells, it plays a vital role when gauging the wine style and, even though it is one of wines loveliest traits, it is sadly often overlooked.
The science behind the colour of wines is in-depth, complex and makes for interesting reading. It opens up a Pandora’s Box of technical terms (and often poses more questions than answers to those without a scientific background!) but there a number of things to keep in mind when peering into your glass.
Before delving into a more in-depth assessment of colour, it is interesting to note that the juice of all but a few grape varieties is clear (A group of grapes known as Teinturier varieties have coloured pulp as well as skins. e.g. Alicante
This bombshell leads us nicely into how red wines derive their colour. Like the nose and the palate, the colour of a red wine depends on the grape variety, the ripeness of the fruit and in turn the vintage. What the majority of red wines have in common is that their colour comes from the juice of the grape (the must) being in contact with the skin before, during and post fermentation (the maceration). Contained in the skins of the grapes are a complex group of phenolics: the most relevant of which being the anthocyanin pigments. Each individual grape variety has different levels of anthocyanin pigments and winemakers must keep a beady eye open to ensure that the correct levels are gently extracted during the winemaking process.
“Anthocyanin pigments are important in determining intensity of colour, but it is the acidity of the juice that is pivotal when looking at the actual hue of the wine”
The size of the berry (the smaller the berry the higher the ratio of skin to juice and the deeper the intensity), the maceration time and the temperature of fermentation all play a role in the colour of a red wine. Varietals with thick skins will produce wines of great intensity (e.g. Cabernet
Sauvignon, Shiraz and Malbec), that will generally be richer in fruit and have higher levels of tannins. Thinner skinned varieties, which have a lower concentration of anthocyanin pigments (e.g Pinot
Noir and Grenache) tend to result in a lighter coloured wine, with a softer ‘prettier’ personality.
Equally as important when looking at the colour of red wines is the level of acidity in the grape juice. Anthocyanin pigments are important in determining intensity of colour, but it is the acidity of
the juice that is pivotal when looking at the actual hue of the wine; with higher acid resulting in a more vibrant and brighter coloured wine.
Red wines tend to lose their colour with age and can go from being beautifully vibrant with bright purple/blue tinges through to ruby, garnet and with a good bit of bottle age end up with a lovely warm brick reddish appearance.
Tend to be light in colour with a red fruit profile ie. Cherry, strawberry. They have low tannin, with medium to high acidity.
e.g. Pinot Noir, Gamay (Beaujolais)
Can vary in colour between light and dark. They have medium tannin, with medium acidity.
e.g. Tempranillo, Merlot, Grenache, Barbera and Sangiovese
Dark in colour and have a dark fruit profile ie. blackberry, blackcurrent. They have high tannin with medium to low acidity and tend to be higher in alcohol.
e.g. Shiraz, Syrah, Malbec, Nebbiolo, Mouvedre, Touriga Nacional, Mouvedre, Zinfandel and Cabernet Sauvignon
Brightly coloured, the fruit profile is best described as primary. They are fresh, bright and lively with distinct acidity and tannin.
Acid and tannin integrate, softening over time. Red wines lighten in colour as they age. They lose their primary fruit characters, becoming what’s known as secondary and tertiary.
White wines can be made from most grape varieties, including those commonly associated with producing red wines (most white Cabernet Sauvignon should probably be approached with caution mind you). In contrast to the production of red wines (where the juice is left to macerate with the skins post crushing), after the fruit for white wines is crushed it is normally quickly pressed off the skins to try and avoid extracting any of the phenolics found in the grape skin; resulting in a wine that is clear and absent of any colour. Racy, youthful whites designed for early drinking can appear to be almost transparent. Some white varietals have a slight pinkish colour to their skins (e.g. Pinot
Gris and Gewurztraminer) that can be picked up by the juice and impart pink tinges to the final wine, but generally ‘white’ wines appear to be clear with slight green tinges at the rim in their youth, and as they develop and age they move through lemony-yellow to golden and onto amber.
Tend to be light in colour with a citrus fruit profile. They have medium to high, zesty acidity.
e.g. Pinot Grigio, Riesling and Vermentino
Medium bodied whites are deeper in colour with medium, softer acidity. Most whites fall into this category.
e.g. Sauvignon Blanc, Chenin Blanc, Fiano, Albarino, Semillon, Verdhelo
Full bodied whites are deep in colour with lower, soft acidity. They have what is best described as a textural/round mouth-feel.
e.g. Chardonnay, Pinot Gris, Gewürztraminer and Viognier
Brightly coloured, a young wine is at its peak level of acidity and fruit character, here referred to as primary. They are fresh, bright and lively.
Acid integrates and softens over time. White wines darken in colour as they age. They lose their primary fruit characters, becoming what’s known as secondary and tertiary.
Pink wines (commonly referred to as Rose) are made by mixing up the red and white wine process to produce a wine with a bit of a mixed personality, combining the freshness of a white wine with some of the lovely characteristic of a red. The juice for pink wines will be left in contact with the skins for a brief period in order the extract a little of the colour from the skin before being drained off and then more often than not being treated like a white wine to ensure that the end result is a lovely aromatic, vibrant wine. Depending on the time left on the skins, pink wines can range from onion skin to salmon right the way through to a pinky purple similar to the colour of some lighter reds.