Foundations

The sequence is short. Grapes are picked when they are ripe, crushed and pressed, and the juice (or, for red wine, the juice together with the skins) goes into a tank or barrel to ferment. Yeast eats the sugar and gives off alcohol and carbon dioxide. Once the sugar is gone, the young wine is separated from the yeast and grape solids, clarified, and matured in tank, barrel or bottle before it is sold.

Grapes are unusual fruit. A ripe grape carries enough sugar to make a wine of useful strength and enough acidity to keep it fresh and stable, and yeast lives on its skin. That is why wine has been made for thousands of years with very little intervention, and why so much of the craft is about decisions: when to pick, how gently to press, what to age the wine in, how long to wait.

Those decisions and the vineyard behind them are what separate one bottle from another. Which grape, grown where, and made how are the three questions every label answers in part. A Chardonnay from a cool hillside fermented in stainless steel and a Chardonnay from a warm plain aged in new oak are the same grape and taste like different wines.

Inside nearly every wine grape, red or white, the juice is pale. The colour and much of the tannin sit in the skins. To make a red wine, the crushed grapes ferment together with their skins for days or weeks (this soaking is called maceration), and colour, tannin and flavour move into the liquid. Winemakers control how much by how long and how gently they extract.

White wine is normally pressed before fermentation, so only the juice ferments. That is why white wines have little or no tannin, and why a white wine can be made from red grapes: Champagne is largely made from Pinot Noir and Pinot Meunier, pressed so quickly that the juice stays clear.

Rosé is made from red grapes given a short soak, from a few hours to a day or two, until the juice turns pink. Some rosé is a by-product of making a deeper red, when a portion of juice is bled off early (saignée). Blending red and white wine to make still rosé is generally banned in Europe, and Champagne is the famous exception.

Orange wine turns the white method around: white grapes ferment on their skins like a red, which gives an amber colour and a little tannin. So red, white, rosé and orange are ways of making wine, not different kinds of grape.

Sweetness is the sugar left unfermented after the yeast has finished, called residual sugar. A dry wine has almost none; a dessert wine can have well over 100 grams per litre. Acidity is the freshness in a wine, the sharpness you get from a lemon or a green apple. It makes your mouth water, and it is what keeps a wine lively and helps it age.

Tannin comes from grape skins, seeds and stems, and from oak. It is not a flavour but a texture: a drying, grippy feel on the gums and inside the cheeks, like strong black tea. It matters mostly in red wines. Alcohol gives warmth and weight, and comes from the sugar in ripe grapes, so warmer places usually make stronger wines. Most table wines sit between about 11 and 15 per cent.

Body is the overall impression of weight and fullness in the mouth: light, like skimmed milk, up to full, like whole milk. Alcohol is the biggest driver, with sugar and the dissolved substances in the wine adding to it.

The five interact, and balance between them is what makes a wine good. Sweetness softens acidity, and acidity keeps sweetness from cloying. Tannin feels harsher against high acidity and softer against fruit or fat. High alcohol can make a wine feel hot and bitter if nothing offsets it.

Wine grapes ripen best in a band of latitudes roughly 30 to 50 degrees north and south of the equator, where the growing season is warm enough to ripen the fruit and not so hot that it is scorched. Within that band, average temperature is the single strongest influence on style.

As grapes ripen, sugar rises and acidity falls. In cool places the fruit is picked with less sugar and more acidity, giving lighter, fresher wines with lower alcohol and flavours of green apple, citrus and red cherry. In warm places the fruit reaches high sugar and lower acidity, giving fuller, stronger wines with flavours of peach, tropical fruit, plum and blackberry.

Temperature is not just a matter of latitude. Altitude cools a vineyard, so high sites in a hot country can ripen grapes slowly. Large bodies of water, ocean breezes and fog moderate heat. Cold nights after warm days (a wide diurnal range) let grapes build sugar by day and keep acidity overnight. That is why a Mendoza Malbec or a Central Otago Pinot Noir can taste both ripe and fresh.

The trade-off is reliability. In a cool region, grapes may fail to ripen in a poor year, so the vintage matters a great deal. In a warm region, most years ripen fully and the differences between years are smaller.

The Old World means the countries where wine has been made for many centuries, chiefly in Europe. Their wines are usually named after the place they come from, and that place carries legal rules about which grapes may be used, how heavily the vines may crop and how the wine is made. The grape is often not on the label at all.

The New World means the regions where wine arrived later, with European settlers: the Americas, Australia, New Zealand and South Africa. Their labels usually name the grape, their rules are lighter, and winemakers are freer to experiment with which grape goes where and how it is made. Each has its own official zones, such as American Viticultural Areas (AVAs) in the United States and Geographical Indications in Australia.

The terms are also used loosely for style: Old World wines as more restrained, savoury and acidic, New World wines as riper, more fruit-forward and more alcoholic. That holds often enough to be useful and fails often enough to be dangerous. Oregon makes Burgundian Pinot Noir, Alsace labels by grape, and plenty of European producers make ripe, modern wines.

The practical lesson: with a European bottle, learn the place and it tells you the grape and style; with a New World bottle, the grape comes first and the region tells you how warm it was.

Most labels carry the same handful of facts: who made it (the producer), what it is called, where the grapes grew, the vintage, the alcohol by volume and the bottle size. Add to that whichever of these apply: the grape, a quality tier, a sweetness term, and words that describe how the wine was aged.

The place is the richest clue. Places nest inside each other, from country to region to subregion to appellation, just as they do in the Regions section of Ampelos. The more precise the place named, the smaller the area the grapes came from, and usually the stricter the rules: Pauillac is a far tighter promise than Bordeaux, which is tighter than France.

The vintage is the year the grapes were picked. It matters most where weather varies a lot from year to year. A wine with no year is a non-vintage blend of several years, which is normal and deliberate for Champagne.

Ageing and quality words are worth learning early. Reserva and Riserva mean extra ageing, with minimums set by each region. Grand Cru and Premier Cru rank Burgundy's vineyards. DOCG and AOC identify protected Italian and French origins. "Estate bottled" (mis en bouteille au château) means the grapes were grown and the wine bottled by the same estate.