What Is Wine? From Grape to Glass
Listen to this lesson
Wine is fermented grape juice. When grapes are crushed, the natural sugars in the juice meet yeast, tiny micro-organisms found on grape skins and in the cellar. During fermentation, the yeast eats the sugar and turns it into alcohol and carbon dioxide. Everything else, from colour to aroma to sweetness, comes from the grape, the place it grew and the choices of the winemaker.
From vineyard to bottle
Grow
Vines are pruned, nurtured and harvested when the grapes reach the right balance of sugar and acidity.
Crush & press
Grapes are crushed to release their juice. For white wine, the juice is usually separated from the skins quickly.
Ferment & age
Yeast converts sugar into alcohol. The wine may then rest in steel tanks or oak barrels before bottling.
Where does the colour come from?
Here is a surprise: the juice of almost all grapes, even dark red ones, is clear. Red wine gets its colour by fermenting the juice together with the dark skins, which release colour, flavour and tannin. Leave the skins in for just a few hours and you get rosé. Press white grapes and ferment the juice on its own, and you get white wine.
🇿🇦 Cape spotlight
In the Cape, harvest usually runs from late January to March, the busiest and most exciting time of year on a wine farm.
🍷 Try this
Next time you eat a red grape, squeeze a little juice onto a white plate. You will see it is almost colourless: the colour is all in the skin.
🧠 Quick check: tap to reveal
🤔 What turns grape juice into wine?
Fermentation: yeast converts the grape sugars into alcohol.
🤔 Why is red wine red?
The juice is fermented with the dark grape skins, which release their colour.
Next up: The Main Styles of Wine: from crisp whites to Cape bubbles