Concept card Process
Red winemaking
In one sentence
Winemaking in which the juice of black grapes ferments with their skins: that contact, maceration, gives the wine its colour and tannins.
From black grapes to red wine
Destemming
Berries are parted from the stems, unless whole bunches are kept.
Time in the vat
Yeasts make alcohol; the skins give up colour and tannin.
Drawing off and pressing
The free-run wine drains off; the pressed pomace gives the press wine.
Malolactic fermentation
Near-universal in reds: it softens the acidity.
Ageing and blending
In tank, large cask or barrique, from a few months to several years.
Key points
- The colour is in the skin: the juice of almost every black grape is colourless.
- Colour comes out mostly in the first days; a longer time in the vat mostly draws out more tannin.
- The cap of skins, pushed up by the gas, is put back into the juice by pumping over or punching down.
- Press wine, more tannic and deeply coloured, can rejoin the free-run wine, wholly or partly, as the winemaker decides.
What it changes in the glass
- The wine's colour, tannin and frame: what maceration drew from the skins and seeds.
- A short time in the vat gives a suppler wine to drink young; a long one builds a frame for ageing.
Not to be confused with…
Grapes are pressed before fermentation: the juice ferments without the skins, so lacks a red's colour and tannin.
Whole, intact bunches under carbon dioxide begin to ferment inside the berry itself, before any pressing.
After drawing off, a vat's free-run wine seems to lack structure. What can the winemaker do?
One question to test yourself: it does not count towards your progress.
Why the skins matter
A red wine's colour comes from anthocyanins held in the skin: the pulp of almost every variety is colourless. Pressed quickly and very gently with no time on the skins, black grapes give an almost clear juice, that of blanc de noirs wines.
- Maceration extracts colour: the anthocyanins in the skin.
- It extracts tannin, also found in the seeds and, if they are kept, the stems.
- It extracts the grape's aroma precursors, which also sit in the skin.
Before fermentation
- The harvest reaches the cellar as fast as possible, to limit oxidation and the berries heating up.
- Destemming removes the stems, whose green, herbaceous tannins would be unwelcome in quantity. In Burgundy or Beaujolais, some whole bunches are sometimes kept.
- An optional cold soak of a few days, before fermentation starts, seeks colour and aroma before alcohol takes over as the main solvent.
Steering the time in the vat
25 to 32 °C
the usual fermentation range for a red, warmer than for a white
Days or weeks
the time on the skins, which sets most of the tannic structure
- Pumping over: the juice is pumped over the cap. Punching down: the cap is pushed down into the juice. The two do not extract in the same way.
- The higher the temperature within that range, the faster the extraction. Above 32 to 35 °C, the yeasts risk stopping and leaving sugar behind.
- Too cold, fermentation slows extraction and can stall as well.
- Pushing extraction beyond what the grapes' ripeness allows gives green, drying tannins.
Free-run, press wine and what follows
Depending on style, pressing comes before the alcoholic fermentation ends (short maceration) or after it (long maceration). Rich in tannin and colour, press wine can unbalance a blend, or give structure to a wine that lacks it.
- Malolactic fermentation, the work of lactic bacteria, happens in tank or barrel. Poorly managed, it exposes the wine to unwanted bacteria and volatile acidity.
- Oak adds tannin and a little oxygen; new oak also gives roasted notes, depending on the toast.
- Parcels, varieties or vats are usually blended before bottling, after any fining or filtration.
To learn it in depth
Related reading
Sources (5)
- Reference bookHandbook of Enology, Volume 1: The Microbiology of Wine and Vinifications— Wiley
- Reference bookThe Oxford Companion to Wine— Oxford University Press
- Reference bookUnderstanding Wine Chemistry— Wiley
- Academic publicationExploring the effects of extended post-fermentation maceration (Technical Review No. 238, technical notes)— Australian Wine Research Institute (AWRI)
- Reference bookWSET Level 3 Systematic Approach to Tasting Wine (SAT)— Wine & Spirit Education Trust