The simple answer is – the skin of the grape.
But surely it’s a little more complex than that? Yes, it is!
Let’s start with a quick look at the beginning of the process of turning those luscious grapes into wine because this has a bearing on what colour the wine will be.
To produce red wine, black grapes are crushed, (sometimes macerated, depending on the winemaker), fermented on their skins, and then pressed – we’ll ignore the rest of the procedure because, although it’s very interesting, it’s not really relevant to this topic.
To produce rosé wine, black grapes are crushed and pressed and/or macerated on their skins for a period determined by the winemaker, then the juice is fermented having discarded the skins.
White wine is made by crushing white grapes, then pressing the juice out, and then fermenting the juice without the skins.
Orange wine (or amber or ramato as it is sometimes described) is made in the same way as red wine but using white grapes not black.
The main thing to note about what I’ve described above is the point at which the skins of the grapes are discarded. Why is this important? Let’s look at each type of wine in a bit more detail.
To make red wine you must first start with black-skinned grapes. As you’ve probably guessed already, the pigment, called anthocyanin, which gives the wine its colour comes from the skin of the grape. The flesh, and therefore the juice, of black-skinned grapes isn’t red. The easiest way to demonstrate this is to peel a black-skinned grape and leave both the flesh and the skin on a piece of kitchen paper for a while. You will see that the flesh has stained the paper very little, whereas the skins have leached a great deal of colour.
After the grapes are crushed, the skins are left in contact with the juice during fermentation, allowing the anthocyanin to be released, staining the wine.
As you would expect, not all grape varieties produce the same levels of pigment. Thinner-skinned varieties like Pinot Noir have less colour pigment, while thick-skinned grapes like Cabernet Sauvignon can create deep-coloured wines.
In addition, climate can affect the amount of pigment that is produced. Generally speaking, black grapes grown in cooler climates have less anthocyanin than those grown in warm climates.
Winemaking techniques, too, can influence the amount of anthocyanin extracted: how long the skins are left in contact with the juice and the temperature at which fermentation takes place can affect how deeply coloured the resulting wine is.
All of this means that red wine isn’t always described as just ‘red’. It is often described in terms of varying hues, from purple (the least intense), through ruby and garnet, finally to tawny. In general, the less intense the colour, the younger the wine: think of a young Gamay (Beaujolais Nouveau) (purple) compared with an aged Cabernet Sauvignon (garnet) – there is a vast difference between the two in terms of colour intensity.
Also, as red wine ages, the colour moves further along the scale towards tawny.
So does this mean that black grapes can only be made into red wine? Again, the short answer is no. Black grapes can be made into rosé or white wine.
Let’s look at rosé wine first. In order to extract just the right amount of colour from the skins, black grapes are pressed and/or macerated before fermentation takes place (unlike red wine where the skins are left in contact throughout fermentation). How vigorously the grapes are pressed – or how long maceration takes – depends entirely on the intensity of colour and depth of flavour the winemaker wishes to achieve. That’s why some rosé wines have only a hint of colour whereas others are almost salmon pink.
And yes, black grapes can be made into white wine. If the juice is extracted and the skins are removed straight away, no pigment is released. Think of Champagne: the classic combination of varieties is Chardonnay (white), Pinot Noir (black) and Meunier (black). In reality, though almost all white wines are made from white-skinned grapes.
Which brings us nicely to white wine: we’ve seen that white wine is made by crushing, pressing, and then fermenting the grape flesh minus the skins. So why isn’t all white wine the same colour, since we know that the colour comes from the skins?
Even at the crushing and pressing stage, some colour will be extracted from the skins, and just as not all black grape varieties produce the same levels of pigment, neither do white grapes. Some white varieties, like Albariño have very green skins, whereas others, like Gewürztraminer, verge on pink – and there is a whole range of hues in between.
But with white grapes, much depends on when they are harvested – if the sugar level in the grapes is low, then the resulting colour is likely to be pale. In addition, intervention by the winemaker will have a bearing on the eventual colour. For example, if wine made from Chardonnay grapes has spent time on oak, then the colour will be deeper and more intense.
Just as we saw that red wines aren’t just described as red, white wines too have a lexicon of their own, ranging from lemon-green, through lemon, to gold and even amber.
But what about orange wines? Well, as we’ve seen, orange wine starts off with white grapes, but the berries are then treated as if they are black ones. In the same way as making red wine, the grapes are fermented with their skins, so colour is extracted in the same way, although the skins of white grapes will carry a great deal less pigment than black grapes. And we know that all grape varieties, be they black or white, do not have uniform skin colour, so orange wine isn’t just orange, there are many hues. Unlike red, rosé, and white wine, however, orange wine doesn’t have its own accepted range of colour descriptors as yet – although I’m sure the wine powers-that-be will come up with one soon enough. (For more information about orange wine, see my previous Blog post ‘The Future’s Bright – The Future’s Orange’, October 11th, 2021.)
And there we have it! In a nutshell, the colour of the wine is primarily determined by the skins – but other factors also come into play.
By Maureen Little