How wine is made

Left alone, grape juice becomes vinegar. The winemaker's entire job is to interrupt that slide at the good part — and every choice about how, when and with what shows up in your glass. This chapter is the recipe book, minus the mystique.

First, the split

blush is a sweetness, rosé is a colour

White wine: press the grapes straight away and ferment the juice on its own. Red wine: crush the grapes and ferment juice and skins together, because that's where the colour and the tannin live. The juice inside almost every red grape is clear — a red wine is a white wine that spent quality time with its own skins.

Rosé sits between, but closer to white than you'd guess. The juice gets a brief skin soak — hours, not weeks — and is then pulled off and fermented pale. One correction while we're here: blush is not a synonym for rosé. Blush describes a sweetness style (think White Zinfandel), while rosé describes a colour. Plenty of the world's best rosés are bone dry.

The fermentation itself is gloriously simple. Yeast eat sugar and give back alcohol, carbon dioxide and heat. That's it — the whole miracle. It also means riper grapes carry more sugar, and more sugar means more potential alcohol. Keep that in your pocket; it explains half the wine world.

The six levers

Everything a winemaker does fits under six headings. The first you already know.

Place

Chapter one covered this: climate is the flavour dial, and the vineyard is a decision made before a single grape exists.

Grape

The variety sets the ceiling. Thick-skinned Cabernet gives dark colour and firm tannin; thin-skinned Pinot Noir gives neither, no matter how hard you try. A winemaker can shape a grape's character but never swap it for another one. Choose the grape, and you've chosen the range of possible wines.

Yeast

Here's the first real fork in the road. Let the ambient yeasts already living on the skins and in the cellar do the work, and you get risk plus character — ferments that stall, and ferments that produce flavours no lab could design. Buy a cultured strain and you get consistency, a ferment that starts on Tuesday and finishes on schedule. Neither is virtue; they're temperaments. And after fermentation, the dead yeast cells (the lees) can be stirred back through the wine for months, feeding it a bready, nutty richness. If a white wine tastes faintly of fresh brioche and hazelnut, someone was stirring.

Malolactic

the butter in your Chardonnay is popcorn chemistry

A second, quieter conversion follows the first — this one run by bacteria, not yeast. They take sharp malic acid, the acid of green apples, and turn it into soft lactic acid, the acid of cream. Nearly every red on Earth goes through it. In whites it's a genuine style choice: block it and the wine stays taut and appley; allow it and the wine turns rounder. A by-product called diacetyl tastes of butter — the same molecule the popcorn industry uses for butter flavouring. That fat, buttery Chardonnay you either love or flee from? Now you know its name.

Oak

3 litres of pure stubbornness

A new oak barrel is a seasoning. It gives vanilla, clove, sweet spice — coconut, if the oak is American. But a barrel only has so much flavour to give, and after three or four fills it goes neutral: a used barrel doesn't season the wine, it just lets it breathe through the grain, softening it slowly. French oak is finer-grained, subtler, and costs more than twice as much as American. The cooper toasts the inside of each barrel over flame, and that toast level is a spice dial — light keeps the fruit forward, heavy pushes toward smoke, coffee and caramel.

My favourite detail in all of this: Bordeaux ages its wine in a 225-litre barrique, Burgundy in a 228-litre pièce. Nobody can give you a real reason. Three litres of difference, defended for centuries, because the neighbours do it the other way.

Time

The last lever is the slowest: oxygen chemistry, running at a whisper through cork and barrel. Tannins knit together and soften. Fresh fruit flavours fade and stranger, better ones arrive — leather, tobacco, forest floor, dried earth. A great old red tastes less like fruit and more like autumn. There's a catch, though. Ageing wines pass through a “dumb phase”, a sulky adolescence when the young fruit has gone and the mature flavours haven't shown up, and a very expensive bottle tastes of very little. Open one then and you'll swear the critics were lying. They weren't. The wine was just mid-sentence.

Bubbles

Sparkling wine is a finished wine sent back to work. In the traditional method — Champagne's method — a still base wine is bottled with a little sugar and yeast, and a second fermentation happens inside the sealed bottle. The carbon dioxide has nowhere to go, so it dissolves into the wine. Then comes the cleanup: the bottles are riddled, tilted and turned until the dead yeast collects in the neck, the neck is frozen, and the plug of frozen sediment is fired out under pressure. The tiny top-up that follows, the dosage, sets the sweetness of the final wine, from bone dry to properly sweet.

The waiting matters as much as the method. Non-vintage Champagne must rest at least 15 months on its lees; vintage Champagne typically rests five or six years. All that time on dead yeast is where the toast and brioche notes come from — Champagne tastes of bakery because it spent years lying on one. Prosecco takes the other road: the second fermentation happens in a big pressurised tank instead of the bottle, which is faster, cheaper and keeps the wine fresh and pear-bright. Not a lesser method — the right method for a wine whose whole charm is fruit.

And the origin story is better than the legend. Bubbles were a fault. Dom Pérignon spent much of his career trying to get rid of them — cold Champagne winters stopped fermentation, spring restarted it in bottle, and cellars full of exploding glass were nobody's idea of success. Meanwhile the British, who liked the fizz, were adding sugar on purpose and had the strong coal-fired glass to survive it.

Sweet shortcuts and fortified detours

ten grapes → one millilitre

Great sweet wine is never made by dumping in sugar. It's made by concentration — by taking water out of the grape. Three ways in. Botrytis, the “noble rot”, is a fungus that punctures and shrivels the grapes, concentrating the sugar while the acid stays; it looks revolting on the vine and produces Sauternes and Tokaji, two of the most beautiful wines on Earth. Ice wine is pressed from grapes frozen solid on the vine — the water stays behind as ice and about ten grapes surrender a single millilitre of nectar. And in Italy they simply dry the grapes on straw mats until they're half raisin, which gives you Amarone and Vin Santo.

Fortified wines take a different route: add spirit. Do it early, mid-ferment, and the alcohol kills the yeast with sugar still unfermented — that's Port, sweet and strong at around 20%. Do it after the ferment finishes dry and you get Sherry, which then ages either under flor, a living blanket of yeast that keeps it pale and saline, or in open contact with air, which turns it nutty and dark — and is blended across decades of barrels through the solera system, so every bottle contains a trace of very old wine.

Madeira is the one wine that abuse improved. Barrels of it sailed through the tropics as ballast, baking in ships' holds and sloshing for months, and came back tasting better than they left. Producers noticed, and to this day they cook Madeira on purpose. Having already survived heat and oxygen, it's nearly indestructible — an open bottle keeps for months on the counter, which makes it the most practical fine wine in existence and, I'd argue, the most underpriced.

The honest trade secrets

Small truths the back label leaves out:

• Many wines are clarified — “fined” — with egg whites, milk casein or isinglass from fish bladders. Traces are removed with the sediment, but it's why a wine isn't automatically vegan.
• Those glassy crystals on a cork are tartrates — “wine diamonds” — completely harmless. Most producers chill the wine before bottling purely so you never see them and never worry.
• Adding sugar before fermentation is called chaptalisation. It's legal in cool parts of France and illegal in the US, and it doesn't sweeten anything — the yeast eat it all. It buys alcohol, not sugar.
• Big commercial brands blend across regions and tanks to hit the same taste every year. That's why the vintage on a supermarket label barely matters — consistency is the product.
• The single biggest decision of the year is the pick date. Pick early and the wine is fresh, tart, lighter. Wait, and it turns jammy and strong. Everything else in this chapter adjusts a wine; the pick date defines it.

None of this is scandal. It's craft, and now it's craft you can see through the glass.

next: nine styles, every bottle on earth