Winemaking
Once grapes reach the winery, nothing is automatic. Keep the stems? Break the berries? Ferment with the skins? Use steel, concrete or wood? The choices start quickly — and they add up.
One grape, several possible routes
For most red wine, the juice ferments with the grape skins. That contact is where much of the colour, tannin and some aroma compounds are extracted.
Step 1
Remove unwanted fruit, leaves or damaged bunches where necessary.
Step 2
Stems may be removed, partly retained or used as whole clusters depending on grape, ripeness and style.
Step 3
Some berries may be gently broken; others can remain largely intact.
Step 4
Yeast turns sugar into alcohol while skins and seeds remain in contact with the juice.
Step 5
Floating skins may be punched down, pumped over or otherwise mixed to control extraction.
Step 6
The young wine is separated from the skins after or near the end of fermentation.
Step 7
Often encouraged in reds to soften sharp malic acidity and improve microbial stability.
Step 8
Steel, concrete, wood or other vessels may be used before bottling.
What is actually happening in there?
No. Despite the name, this need not involve anything remotely violent. Crushing can be as gentle as breaking a few berries so juice, skins and yeast can get acquainted; some winemakers deliberately leave plenty of berries or whole bunches intact.
Yeast gets the rather important job of eating grape sugar and leaving alcohol, carbon dioxide and heat behind. It also produces a swarm of aroma compounds on the way, which is why fermentation is not merely chemistry homework — it is one of the biggest flavour decisions in the cellar.
Because the juice inside most red grapes is surprisingly pale. Much of the colour and tannin lives in the skins and seeds, so time, temperature and mixing decide how much of that ends up in the wine.
The name makes it sound like another alcoholic fermentation, but bacteria are usually doing the work. They turn sharper malic acid into softer lactic acid, making the wine feel rounder and, in some cases, bringing those familiar buttery or creamy notes.
Lees are the spent yeast and fine solids left when fermentation has finished. Stirring them through the wine can build texture and bring creamy, savoury or bready notes. Useful when you want that effect; needless faffing when you do not.
Mostly to stop oxygen and unwanted microbes making decisions of their own. Wine produces some sulphites naturally too, so the sensible question is not whether they exist but how much was used, when, and for what reason.
Filtration removes particles and, depending on the filter, microbes. Attack a wine too aggressively and texture can change; use it carefully and it is simply a way of gaining clarity and stability before the bottle leaves the cellar.
Not really. Grapes do not organise their own harvest, choose a fermenter and bottle themselves. “Natural wine” is better understood as a loose family of lower-intervention farming and cellar choices, not a single recipe or a claim that nobody touched anything.
Whole bunches, carbonic maceration, lees ageing and filtration are not medals of honour. They are tools. What matters is what the winemaker is trying to change — aroma, tannin, texture, colour, stability or freshness — and whether the result is any better for it.
Some or all bunches go into the fermenter with stems attached, changing extraction, fermentation dynamics and aroma.
Intact berries begin an intracellular fermentation in a carbon-dioxide-rich environment before conventional yeast fermentation finishes the job.
White grapes stay with their skins during fermentation, building colour, tannin and texture.
Red grapes sit cool before alcoholic fermentation to encourage some early extraction while delaying yeast activity.
Bacteria convert malic acid to lactic acid, usually softening acidity and changing texture.
Wine rests on spent yeast after fermentation, sometimes with stirring to build texture.
A fining agent binds with selected compounds so they can be removed, improving clarity or changing texture.
Wine passes through a filter to remove particles and, in some cases, microorganisms before bottling.
Winemaking becomes much easier to taste when you compare wines that differ mainly in one choice.
Skin contact
White wine vs skin-contact white from the same grape.
Oak
Same grape with and without oak maturation.
Whole bunch
Same variety with different stem inclusion.
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