Wine, Explained

Harvest. Grapes are picked when sugar, acid and tannin reach the balance the winemaker wants — by hand for delicate fruit, by machine for large volumes.

Crushing and pressing. White grapes are usually pressed immediately so the juice never sits on the skins. Red grapes are crushed and fermented with their skins, which supply colour and tannin.

Fermentation. Yeast converts sugar into alcohol and carbon dioxide over one to four weeks. Cooler fermentations preserve fruit aromatics; warmer ones extract more structure.

Maturation. Wine rests in stainless steel, concrete or oak. Oak contributes vanilla, spice and a slow, gentle exposure to oxygen.

Blending and fining. Lots from different parcels are assembled, then clarified and stabilised.

Bottling. Some wines are released within months; others are cellared for years before sale.

A grape variety is a distinct cultivar of Vitis vinifera, each with its own thickness of skin, natural acidity, sugar potential and aromatic signature.

Thick-skinned varieties such as Cabernet Sauvignon give deeply coloured, tannic wines. Thin-skinned ones such as Pinot Noir give pale, perfumed, delicate wines.

The same variety tastes different depending on climate: Syrah is peppery and restrained in the cool northern Rhône, and rich and sweet-fruited as Shiraz in warm Barossa.

New World labels usually name the grape; European labels usually name the place, and the permitted grapes are implied by the appellation.

Almost all grape juice runs clear. Red wine gets its colour, tannin and structure from fermenting with the skins; white wine is pressed off them first.

That single choice cascades: reds are typically fuller, more tannic and served warmer, whites are crisper, more aromatic and served cold.

Rosé sits in between — a few hours of skin contact for colour, then pressing. Orange wine reverses the logic: white grapes fermented on skins for days or weeks.

Sweetness is residual sugar left after fermentation, measured in grams per litre. Bone dry is under 4 g/L, off-dry roughly 10–30 g/L, and dessert wines can exceed 150 g/L.

Fruity is not the same as sweet. A dry Riesling can smell intensely of peach and still finish completely dry.

Sweetness is balanced by acidity. Great sweet wines — Sauternes, Mosel Riesling, Tokaji — are also intensely acidic, which is why they taste fresh rather than cloying.

Tannins are polyphenols found in grape skins, seeds and stems, and in oak barrels. You feel them rather than taste them: a drying, grippy sensation on the gums.

They are natural preservatives, which is why tannic wines such as Nebbiolo and Cabernet Sauvignon can age for decades, softening as the tannins polymerise.

Protein and fat soften tannin, which is why steak and hard cheese make tannic reds taste smoother.

Acidity makes your mouth water. It comes mostly from tartaric and malic acid in the grape, and falls as grapes ripen — so cool climates give higher-acid wines.

High acidity reads as crisp, zesty, mineral; low acidity as soft, round, sometimes flabby.

Malolactic conversion turns sharp malic acid into softer lactic acid, giving the creamy texture typical of oaked Chardonnay.

Primary aromas come from the grape itself: citrus, berry, stone fruit, herbs, flowers, pepper.

Secondary aromas come from winemaking: yeast and lees give bread and brioche, malolactic conversion gives butter, oak gives vanilla, clove and smoke.

Tertiary aromas come from age: dried fruit, leather, tobacco, forest floor, nuts and honey.

Look. Tilt the glass over a white surface. Colour hints at age, grape and concentration.

Swirl. Agitation releases volatile aromatic compounds.

Smell. Take short sniffs and name what you find before analysing it.

Taste. Note sweetness, acidity, tannin, alcohol, body and flavour intensity.

Conclude. Judge the length of the finish and whether the parts are in balance.

Temperature: a steady 12–14°C. Fluctuation is more damaging than a slightly warm cellar.

Darkness: ultraviolet light degrades wine, which is why fine bottles are in dark glass.

Humidity: around 70%, so natural corks stay swollen and airtight.

Position: store bottles on their side under cork, and keep them away from vibration.

Sparkling 6–8°C, light whites and rosé 8–10°C, full whites 10–13°C, light reds 13–15°C, full reds 16–18°C. Most reds are served too warm and most whites too cold.

Decant young tannic reds for aeration, and old reds carefully to leave sediment behind.

Serve lighter before fuller, dry before sweet, young before old.

Pour a third of the glass: the empty space is where the aromatics gather.

Producer: the name of the estate or brand, usually the largest text on a European label.

Region or appellation: AOC in France, DOCG in Italy, DO/DOCa in Spain, AVA in the United States. The tighter the appellation, the stricter the rules.

Vintage: the year the grapes were grown. Non-vintage, common in Champagne, means a blend of years.

Other clues: alcohol by volume hints at body and ripeness; terms such as Reserva, Riserva or Grand Cru indicate ageing or vineyard classification.