Under the Microscope: The Differences Between Red, White, Rose & Orange Wine.

Wine History & Culture

Fundamentally, red wines are made with red grapes, and white wines are made with white grapes… but we can delve a little deeper than that

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Nearly all wines are originally made from one species of grape called Vitis Vinifera and Ampelographers (those who study grapes) believe that the first Vitis Vinifera grapes were black grapes (red wine grapes) and that a natural mutation created the first white grapes.

For example, Pinot Noir (a black grape), Pinot Gris (a pinkish-grey grape), and a Pinot Black (a white grape) all share the same DNA.

There are different processes used in making red, white, rosé and orange wine however, the colour of the wine all stem from skins and seeds of the grape.

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- Red wine is made by pressing the red grapes and fermenting the juice with the grape skins adding the pigment, tannins and structure to the wine.

- White wine is made by pressing the white grapes and fermenting the juice without the skins creating a lighter colour and fresher flavour.

- Rosé sits in the middle and is made from red grapes but the skin contact with the juice during fermentation is much shorter, giving the beautiful pink hue to the wine.

- Orange wine (not made from oranges) is an ancient practice that is making a modern comeback, where the juice of pressed white grapes is fermented with the skins and seeds adding tannin, structure and that noticeable orange colour.

There are chemical differences between red grapes and white grapes. In white grapes the skins are full of molecules called Flavonoids and their colour varies with hues of green, yellow, straw or in some cases even a light grey. In contrast, in red grapes the skins contain molecules called Anthocyanins, whose colour varies from red to purple.

The Anthocyanins have the chemical property of absorbing green light and reflecting the red, blue and purple wavelengths of light, hence the red-to-purple colour perceived in our eyes. There are different forms of the Anthocyanin molecules and it’s the pH of the wine that determines the percentage of each form of Anthocyanin present. Therefore, lower pH (more acidic wines) will have more of a reddish hue or ruby in colour (e.g. a Sangiovese), whereas higher pH (less acidic wines) will have more of a purple hue in colour (e.g. a Syrah or Malbec).

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The colour in grapes is primarily located in the skin, the pulp inside the grape is always very pale and hardly has any colour – this is why it is possible to make white wine with red grapes, e.g. Blanc de Noirs. However, there are a handful of grape varieties that have a dark coloured pulp, these are called Teinturier grapes and produce a very intensely dark coloured juice. Example grape varieties of this would be Alicante Bouschet or Saperavi.

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Interestingly, all the health benefits associated with wine are found in the skins and seeds of the wine grape. The tannin in red wine contains procyanidins which protect against heart disease and wines from Sardinia and Southwest France tend to have higher amounts of procyanidins. There is also an antioxidant in red wine called Resveratrol that is found in the skins of the grapes which can help lower low-density lipoprotein (LDL) cholesterol (the bad cholesterol), prevent blood clots and lower inflammation.

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Sources

Strega

Mayo Clinic

Wine Folly

Vivino

Guildsomm

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