How to Harvest Grapes for Winemaking?

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Ever wondered how grapes become wine?

During a harvest workshop, I discovered every stage — from the moment grapes are picked to when they start fermenting.

I’m sharing this experience as a simple, universal guide, because the harvest process is pretty similar everywhere — whether you’re in Europe, Japan, England or beyond.

Let’s follow the grape’s journey from vine to vat together!

Harvesting is the first step in turning grapes into wine. Winemakers decide when to harvest by tasting the grapes and checking sugar and acidity levels. Grapes are then picked — by hand or machine — and gently crushed to release the juice without breaking the seeds. Next comes pressing, which separates the juice from the skins and pulp. The juice flows into tanks for fermentation, where yeasts transform sugar into alcohol. Temperature control is crucial: cooler fermentations preserve fruity aromas, while warmer ones help extract color and structure in reds. After fermentation, the wine is clarified using natural fining agents like pea protein to make it clear and stable. Finally, it’s aged, blended, and bottled. Each of these steps — from grape to glass — shapes the flavor, color, and balance of the final wine.

Step 1 – Picking, Destemming and Crushing

The first question every winemaker asks: when is the right time to harvest?
To decide, they taste the grapes (are they sweet enough?) and also test them in the lab to check sugar and acidity levels.

Once ready, the grapes can be picked by hand or mechanically.
A mechanical harvester shakes the vines so the grapes fall into a tank — already separated from their stems.

The harvester then pours the grapes into a truck to be brought to the cellar.

These mechanically harvested grapes are then poured into a crusher before being poured (under the effect of gravity) into the press.

Crushing bursts the skin of the grapes and releases the drop juice. Of course, the seeds should not be crushed. They would then release their bitter tannins, making the wine astringent.

Step 2 – Pressing the grapes

Pressing means separating the juice from the solid parts (skins and pulp). For white and rosé wines, pressing happens before fermentation. For red wines, it happens after.

Most wineries use a pneumatic press.

How does it work? It consists of an inflatable rubber membrane placed inside a perforated horizontal stainless steel cylinder, which allows pressing in a controlled way. For rosés, the time of pressing is about an hour and a half to two hours.

The juice then flows directly into tanks, with as little contact with air as possible, to keep it fresh and clean.

Not all grape juice is the same!
The first juice extracted during pressing — called the free-run juice — is usually lighter, fresher, and more delicate.
As pressing continues, the juice that follows becomes richer, deeper in color, and more structured, with a touch more tannin.

Because of this, winemakers often separate the different juices from each stage of pressing. Each batch is then fermented on its own, and later blended to create the final style they want. This blending step is key to achieving balance between freshness, color, and texture.

For example, a variety like Syrah produces a very colorful juice, even when used for rosé. In that case, winemakers often use the direct pressing method — crushing and pressing the grapes straight away, just like with white wines — to get a beautiful pale pink color without too much tannin.

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Another common technique for rosé is short maceration.
Here, red grapes are left in contact with their skins for a few hours to extract a touch of color and aroma before pressing.
The longer the maceration, the deeper the color and flavor — that’s how winemakers craft everything from the palest blush to vibrant salmon-pink rosés.

Step 3 – Fermentation: When Juice Becomes Wine

This is where the real magic happens — fermentation is when grape juice turns into wine!
Yeasts (tiny natural organisms) eat the grape’s sugars and transform them into alcohol and aromas.

Winemakers can take two approaches:

• Use indigenous yeasts, which are naturally found on the grapes and in the winery, or
• Add selected yeasts, chosen for their reliability and flavor profile.

Both have their charm. Natural yeasts can create incredible aromatic complexity but are less predictable. Selected yeasts, on the other hand, give the winemaker more control — they make sure fermentation starts smoothly and stays consistent from one batch to another.

Before being added to the grape juice, these yeasts are gently rehydrated in warm water, then cooled down to match the wine’s temperature — a bit like waking them up slowly before they get to work.

Temperature control during fermentation is absolutely essential.
If the tank gets too warm, the yeasts stop working; if it’s too cold, fermentation slows down.
Cooler fermentations (around 12–15°C) preserve fresh, fruity and floral notes, while slightly warmer ones bring out richer, rounder aromas — especially for white wines.

For reds, it’s the opposite: higher temperatures help extract color, tannins, and structure from the skins.

Here’s a simple example: during the harvest workshop I attended, the winemakers showed us how temperature can completely change a wine’s aroma.

When they fermented their Sémillon at around 10–15°C, the wine developed sweet, candy-like notes — think strawberry sweets or banana! By slightly increasing the temperature to 17°C, they brought out more freshness and balance, allowing the grape’s natural aromas to shine through.

In fact, when white wines ferment too cold, they can lose their delicate fruity and floral notes, resulting in artificial candy-like flavors. That’s why winemakers carefully monitor every tank throughout fermentation.

Modern wineries are now equipped with precise cooling systems to keep the temperature just right — ensuring each wine develops its ideal aroma and character.

Step 4 – Managing the cap

When red grapes ferment, their skins rise to the surface and form what’s called the “cap.”

To make sure color and flavor are evenly extracted, winemakers gently move the juice around using two main techniques:

• Pumping over – drawing wine from the bottom of the tank and pouring it over the top,
• Punching down – pushing the skins back into the liquid.

Pumping over is the softer method — it oxygenates the wine, keeps the temperature balanced, and ensures the grapes are treated with care.

Step 5 – Small adjustments, big impact

During fermentation, winemakers check their wines every single day.
They take small samples to analyze the wine’s progress — monitoring sugar levels, acidity, and temperature to make sure everything stays on track.

Sometimes, a few gentle adjustments are needed to keep the balance right.
For example, the winemaker might slightly raise the acidity by adding a touch of tartaric acid to make the wine taste fresher — especially in warm regions where grapes naturally contain less acid.

Increasing sugar levels, on the other hand, is rare and often restricted. In many regions, winemakers are not allowed to add sugar or concentrated grape must to boost alcohol levels, ensuring the final wine reflects the natural ripeness of the fruit.

These tweaks are minimal, but they help the winemaker guide the wine toward harmony, without ever losing its authenticity.

Step 6 – Clarification of musts

Once fermentation is complete, the young wine can look a little cloudy — that’s completely normal. To improve its clarity and stability, winemakers often use a process called fining or filtering.

Today, many prefer natural, plant-based fining agents, such as pea protein. It’s non-allergenic, eco-friendly, and doesn’t affect the wine’s flavor. This gentle technique helps remove small particles and refine the color, giving the wine a bright, clean look.

For rosé wines, fining also softens overly intense colors and reduces compounds that might make the wine appear too orange or dull. The result? That beautiful, delicate pink we all love in a glass of rosé.

Wrapping it all up

From grape to glass, the harvest marks the start of the wine’s journey.
Each step — from picking and pressing to fermentation and clarification — shapes its personality.
It’s a mix of science, timing, and a lot of passion.

What struck me most during the harvest was how every decision matters. A few degrees, a few hours, or a small adjustment can completely change what ends up in your glass.

So next time you sip a wine, take a moment to think of the hands and choices behind it — all the invisible work that turns simple grapes into something so full of life and story.

Where to next?

Want to Experience It Yourself? Book your private wine tasting!

There’s no better way to understand wine than to see, smell, and taste it for yourself.
Join me for a private wine tasting where I’ll walk you through how wines are made — from vineyard to bottle — and, of course, help you taste them like a pro.

How to taste wine like a pro?

Now that you know how wine is made, it’s time to learn how to taste it like a pro — how to spot the aromas, judge the structure, and truly understand what’s in your glass.