The colour of Red and Rosé wine comes from the skin of the grapes. When you crush a white grape, keep the grape juice, discard the skins and allow the alcoholic fermentation to take place, you end up with a white wine.
If you crush red grapes and discard the skins, the juice is also clear so you will get a white wine from these grapes. However, if you leave the red skins in the mix during fermentation, then the colour leaches out of the skins and by the time all of the sugar has been fermented into alcohol (say 14 – 20 days), you get a full red wine.
If you take the skins out shortly after the crush, say after barely 2 or 3 hours, you will end up with a pale rosé like Cimels (above left). Or you can leave the skins for longer, say 48-72 hours and you will get a much deeper rosé like Ch. d’Or et de Gueules Trassegum (above right). Note the colour is not an intense pink, but more of a prawn colour, or onion skin colour.
Ouitside Europe, you are allowed to add a splash of red wine to white wine to make a pink wine. More of a food colouring than a winemaking technique! These “coloured” pink wines really are pink, not natural prawn-orange and do not have the same depth of flavour which comes from skin contact. Look at the colour next time you are offered say a Californian Rose.