03 · Making Beginner

How wine is made

Every wine, however simple or complex, passes through the same fundamental stages. Understanding them explains why wines taste the way they do — and why identical grapes from adjacent vineyards can taste very different.

From harvest to bottle

1. Harvest

Grapes are picked when sugar, acidity and phenolic ripeness are balanced. Timing varies by variety and climate — typically August–October in the northern hemisphere. Picked by hand or machine.

2. Sorting and crushing

Bunches or berries are sorted to remove leaves, unripe or damaged fruit. Crushing breaks the grape skins to release juice. Some winemakers use whole-bunch pressing, keeping berries intact.

3. Pressing (whites) / Maceration (reds)

For white wine, juice is pressed from skins quickly and fermented without skin contact. For red wine, skins stay in contact with the juice during fermentation — this is maceration, which extracts colour, tannin and flavour from the skins.

4. Fermentation

Yeast (natural or added) converts grape sugar to alcohol and CO₂. This is the core transformation: grape juice becomes wine. Temperature control affects the character of the final wine — cooler fermentation preserves aromatic freshness.

5. Pressing (reds)

After maceration, the liquid (free-run wine) is drained off the skins. The remaining skins are then pressed to extract the press wine, which is richer in tannin and colour. The winemaker decides how much press wine to add back.

6. Maturation

Wine rests — in stainless steel (preserving fresh fruit), oak barrels (adding vanilla, spice, oxygen exposure), or concrete or amphora (neutral but allowing micro-oxygenation). Duration ranges from weeks to years.

7. Fining and filtration

Optional steps to clarify the wine and remove unwanted particles. Some winemakers skip both for minimal-intervention wines, which may throw a natural sediment in the bottle.

8. Bottling

The finished wine is bottled under inert gas to prevent oxidation, then sealed with cork, screwcap or alternative closure. The bottle is labelled and dispatched.

The core transformation

Everything in winemaking is a variation on one chemical equation: sugar + yeast = alcohol + CO₂. The winemaker's job is to manage this transformation — deciding when to pick, how long to macerate, whether to use oak, and when to bottle. Each decision leaves its mark on the finished wine. A hot fermentation strips aroma; a cold one preserves it. Long maceration builds tannin; short maceration produces a lighter red or a rosé. New oak adds flavour; old oak adds texture without flavour.

The style of wine you see on the label — dry, sweet, sparkling, fortified — reflects specific decisions at specific points in this chain. For how these decisions differ between red, white, rosé and sparkling wine, see the Red, white, rosé and sparkling methods guide.

Key processes in the winemaking process

Understanding how wine is made begins with the winemaking process at its core: fermentation in winemaking. During fermentation, yeast consumes natural grape sugars and converts them into ethanol (alcohol) and carbon dioxide — this single transformation is what turns grape juice into wine. Temperature, yeast strain, vessel type and duration all influence the final character. Cool fermentation (10-15 °C) preserves fresh fruit aromas in white wines; warm fermentation (25-32 °C) extracts colour, tannin and body in reds. The wine ingredients are remarkably simple: grapes, yeast (natural or cultured), and in most cases a small amount of sulphur dioxide as a preservative. Some producers add fining agents (bentonite, egg whites) for clarity, but minimal-intervention winemakers skip these steps entirely.

Malolactic fermentation — a secondary bacterial process distinct from alcoholic fermentation — converts sharp malic acid into softer lactic acid, reducing perceived acidity and adding a buttery, creamy texture. Malolactic fermentation is standard in virtually all red wines and in full-bodied whites like Chardonnay; it is deliberately avoided in aromatic, high-acid whites (Riesling, Sauvignon Blanc) where crispness is the goal. Another critical concept is lees wine ageing — resting wine on its dead yeast cells after fermentation, which adds biscuity, toasty complexity and a rounder mouthfeel. Lees wine ageing is essential to Champagne production and is widely used in white Burgundy.

The WSET winemaking curriculum and GuildSomm production resources both cover the full winemaking process in systematic detail. For a deeper look at how fermentation temperature, oak choice and ageing decisions shape specific wine styles, see the red, white, rosé and sparkling methods guide.

Sources: WSET (winemaking curricula), OIV (oenological standards), AWRI (fermentation science and winemaking research), UC Davis Viticulture & Enology (winemaking science reference). Last updated: 2026-10-15. Corrections via the contact form.

Questions

About making wine.

What is the difference between red and white winemaking?

The fundamental difference is skin contact. White wine is made by pressing grapes quickly and fermenting only the juice, away from the skins. Red wine is made by fermenting the juice together with the skins — this is maceration, and it extracts the colour, tannin and much of the flavour complexity that defines red wine. Rosé sits in between: a short maceration period before pressing gives colour without full tannin extraction. The Red, white, rosé and sparkling methods guide covers this in more detail.

What does fermentation actually do?

Fermentation is the conversion of sugar to alcohol by yeast. Yeast consumes glucose and fructose (the natural sugars in grape juice) and produces ethanol (alcohol) and carbon dioxide as byproducts. The CO₂ escapes from open-top fermentation vessels; it is captured in sparkling wine production. Fermentation ends when all sugar is consumed (producing a dry wine) or when it is deliberately stopped early (leaving residual sugar for sweetness). The alcohol level in the finished wine reflects how much sugar the grapes contained.

What does oak do to wine?

Oak barrels add flavour compounds (vanilla, coconut, toast, smoke), allow slow micro-oxygenation which softens tannin and rounds acidity, and extract tannins from the wood itself. New barrels impart more flavour than old ones. Larger barrels impart less flavour per volume than small (225-litre Bordeaux) barrels. Some winemakers add oak chips or staves to stainless steel tanks to achieve oak flavour without the oxygenation. The What oak does to wine guide covers this in full.

What is natural wine?

Natural wine has no legal definition but broadly refers to wine made with minimal intervention: native yeasts for fermentation, no fining or filtration, no added sulphites (or very low sulphite additions). The goal is to reflect the vineyard as purely as possible. Critics argue that without sulphites some natural wines are unstable or faulty. Proponents argue that conventional winemaking masks terroir. Natural wine sits on a spectrum — it is not binary.

Why is wine sometimes cloudy?

Cloudiness (turbidity) in wine usually means unfined and unfiltered production, leaving natural proteins, yeast particles or tartrate crystals in suspension. This is intentional in many natural and low-intervention wines and does not indicate a fault. Tartrate crystals — harmless white crystals sometimes found in white wine — precipitate when wine is chilled quickly. A cloudy wine that smells off or vinegary, however, may indicate a fault rather than intentional minimal intervention.

What is fermentation in wine?

Fermentation is the core process of winemaking: yeast consumes the natural sugars (glucose and fructose) in grape juice and converts them into ethanol (alcohol) and carbon dioxide as byproducts. The chemical equation is: sugar + yeast = alcohol + CO₂. In open-top vessels, the CO₂ escapes; in Champagne production it is captured in the bottle during a second fermentation, creating the bubbles. Fermentation ends either when all sugar is consumed (producing a dry wine) or when the winemaker stops it early, leaving residual sugar for sweetness. Temperature control during fermentation significantly affects the final wine character — cooler fermentation (10–15 °C) preserves fresh aromas; warmer fermentation (25–30 °C) extracts more colour and tannin in red wines. See the fermentation glossary entry.

What are the main wine ingredients?

The ingredients of wine are remarkably simple. At minimum, wine requires only grapes and yeast — naturally occurring yeasts on grape skins can ferment juice into wine with no other additions. In practice, most winemakers add sulphur dioxide (SO₂) as an antioxidant and antimicrobial preservative. Other permitted additions include: tartaric acid (to adjust acidity in warm-climate wines), sugar (in cool regions where grapes lack natural sugar — a process called chaptalization, banned in some areas), fining agents (egg whites, bentonite clay, casein) to clarify the wine, and oak chips or staves as alternatives to barrel ageing. Organic wine restricts synthetic chemical additions; natural wine aims for minimal additions beyond grapes and native yeast. The EU ingredient labelling regulation (from December 2026) will require all wines to declare their full ingredient list. See the how to read a wine label guide for upcoming labelling changes.

What is malolactic fermentation and why does it matter?

Malolactic fermentation (MLF) is a secondary bacterial conversion — not a yeast fermentation — that transforms sharp malic acid (the acid found in green apples) into softer lactic acid (the acid found in milk). The process is carried out by lactic acid bacteria, primarily Oenococcus oeni. MLF reduces total acidity, softens the palate impression and can introduce a characteristic buttery, creamy character (from the compound diacetyl). It is standard practice in virtually all red wines and in full-bodied whites like oaked Chardonnay. Winemakers control MLF through temperature and SO₂ management — they can encourage it, block it entirely, or allow it partially. Wines that skip MLF retain higher acidity and a crisper, more angular profile. See the fermentation glossary entry for how MLF differs from alcoholic fermentation.

What is biodynamic wine?

Biodynamic wine comes from vineyards farmed according to biodynamic agriculture — an approach developed by Rudolf Steiner in the 1920s that treats the farm as a self-sustaining ecosystem. It goes further than organic farming: no synthetic pesticides or fertilisers, specific preparations applied on lunar and cosmic calendar schedules, and a holistic approach to soil health. The certification body is Demeter International. Biodynamic viticulture is practised by some of the world's most respected estates (Leroy, Zind-Humbrecht, Chapoutier). The evidence for the lunar calendar element is debated, but biodynamic vineyards consistently demonstrate excellent soil health and biodiversity.

What is organic wine?

Organic wine is made from grapes grown without synthetic pesticides, herbicides or fertilisers — the farming must be certified organic by a recognised body (EU Regulation EC 834/2007 in Europe; USDA NOP in the US). In the EU since 2012, "organic wine" also specifies limits on sulphite additions: lower than for conventional wine. Organic certification covers farming but not necessarily winemaking interventions (fining agents, additives). Organic wine does not taste different from conventional wine by definition — the distinction is about farming practice and environmental impact, not flavour profile.