How Is Wine Made? An Introductory Guide

It’s a question with thousands of answers. If you’re curious about what goes on behind the scenes in winemaking, this might just be the start of a lifelong fascination.

Winemaking is an ancient craft that has been refined and transformed over thousands of years. Today, it looks far different than it did in 6000 B.C. — or even 100 years ago. Commercialization, scientific knowledge, experimentation, and advances in technology have all played roles in shaping the wines available today.

While many wineries have embraced modern technology to stay competitive, others continue to thrive by using traditional methods that create the distinctive flavors we still cherish.

But unlike jewelry or fashion, the nuances of winemaking aren’t primarily tied to commercial value (although that does play a role). Instead, winemaking is about the process. Each wine goes on a unique journey, developing its character through the decisions made along the way from vine to bottle. It's through the details that we can uncover the complexities in each bottle and brand.

Let’s explore how wine is made, the role played by modern technology, and how these elements come together to create the flavors and styles we love.

Hundreds of Little Decisions

In some ways, wine is as natural as regular plant growth. Fermentation (the process of turning sugar into alcohol) occurs naturally with crushed fruit. It just needs a little nudge in the right direction.

In winemaking, humans step in to shape the taste and character of wine. While certain steps are consistent across all types of wine, there is immense variety in how winemaking differs by type, brand, region, and winery. Much like craft beer, spirits, bread, or any other artistic endeavor with food or drink, the vision of the winery and winemaker defines the process.

Wine is the result of numerous decisions (about 400 on average) made by the winery at every stage — from the vineyard's region and harvest schedule to the speed of grape crushing and the choice of fermentation method. Even the bottling process plays a role.

Though winemaking has a general roadmap, even the most experienced winemakers adapt core steps in the process and intentionally subvert traditions to achieve unique flavors.

Wine is all about choices, and the winemakers that have consistently made the right choices have become the heroes of winemaking, creating the wines we admire today.

DISCLAIMER: Explaining every variation of the winemaking process would require volumes. Here is a simplified overview to help you appreciate the artistry and complexity behind your favorite bottles of wine. To learn more, check out our Wine 101 and Wine 201 specialty courses.

Stage 1: Growing

Winemaking starts with the grapes, and where they’re grown is a crucial decision. The vineyard’s location, weather, soil, and vine management all influence the flavors and characteristics of the final wine.

“Terroir” is a common term in the wine world. It refers to the combination of soil, climate, environmental factors, and the winemaker’s decisions — all of which contribute to the grape’s qualities. For example, grapes grown in cooler climates tend to produce wines with higher acidity. Warmer climates yield richer, riper flavors.

Interestingly, poor soil conditions are often prized in winemaking. The struggle to grow forces roots to dig deep into the ground, concentrating the flavors in the fruit. Even within a single vineyard, slight variations in soil can result in two wines with completely distinct profiles — the aromas, tastes, and textures that define their flavors.

Types of Wine Grapes

Not all grapes are fit for winemaking. For instance, your favorite grape juice is probably produced with concord grapes, but wine is produced from different grape varieties (many from the vitis vinifera species) that produce tannins (as with red grapes), acidity  and other characteristics we come to expect from wine.

The type of grape grown is the primary driver of flavor. Here are some common wine grape varieties and the qualities they generally bring to wine:

Vineyard Location

In addition to the vineyard’s soil conditions, location and vintage (the harvest year) play important roles in wine pricing and reputation. Certain regions, like Bordeaux or the Napa Valley, are associated with high-quality production.

Marketing also ties into production decisions, as a wine’s perceived prestige affects how wineries approach everything from grape selection to bottling and labeling. The more money a winery can charge for a bottle, the more care and control it can exert over the viticulture, the winemaking process, and the style of wine.

Stage 2: Harvesting

Harvesting is where timing and technique meet precision. Deciding when to pick the grapes is one of the most important steps in shaping the final wine.

Timing Is Everything

The ripeness of the grapes determines key characteristics like sugar content, acidity, tannins, and flavor precursors.

• Less-ripe grapes lead to wines with higher acidity, lower sugar (which converts to alcohol during fermentation; more on that later), lower alcohol, and more green flavor—ideal for crisp, refreshing styles.

• More-ripe grapes result in wines with higher sugar (which converts to alcohol during fermentation; more on that later), and lower–acidity grapes tend to lead to richer wines with higher alcohol content but lower acidity.

Perfectly ripe grapes strike a balance, ensuring that flavors, structure, and alcohol levels complement one another. Some wineries pick at a specific time of day, with some harvesting at night when grapes coming off the vine are cooler in temperature.

Harvesting Methods

• Handpicking: Picking grapes by hand is the gold standard for quality. This ensures that only the best grapes make it into the wine and allows for extremely precise control over the harvesting process.

• Mechanical Harvesting: Many wineries use automatic harvesting machines. These can cover larger areas quickly, making them cost-effective for large-scale wineries. While older machines were less precise (and therefore rarely used for fine wines), modern machines can effectively pick without damaging the fruit. Today, mechanical harvesting is considered even in fine wine production, unless the winery is aiming for a certain style (i.e., botrytis).

In some wineries, harvest season is a community celebration, with locals and workers coming together to hand-pick grapes at dawn for optimal freshness.

Stage 3: Sorting

Once the grapes reach the winery, the next step is sorting, a critical phase of winemaking that ensures only the best fruit makes it into the bottle.

At the very least, winemakers must remove any unwanted materials (also called “MOG” or “Materials Other than Grapes”), such as leaves, stems, or dirt, left over from the harvest. This helps maintain the purity of the wine and prevents off-flavors during fermentation. Winemakers will also remove underripe, damaged, or rotten grapes, as these can negatively affect the final product.

Some wineries de-stem the grapes before sorting, while others let the crushing equipment handle this automatically. Some may even ferment the entire cluster.

• With stems: Sometimes, winemakers intentionally leave grapes to ferment on the stems. Stems may also add structure and complexity to certain wines, particularly reds.

• Without stems: Removing stems avoids the risk of adding bitter or astringent flavors to the wine.

Every winery has its own approach to sorting, and these decisions influence everything from the wine’s texture to its overall balance.

Stage 4: Crushing / Pressing

Once sorted, most wineries crush the grapes next, but there are exceptions for certain styles of wine or production methods. Crushing is a process that breaks the fruit to release its juices. This juice, along with bits of skin, pulp, and seeds, is called “must” and serves as the base for fermentation. For red wines, the skins and seeds are fermented together. For white wines, the skins and seeds are separated from the juice so that only the juice is fermented.

While stomping grapes by foot persists in certain wine traditions, most wineries today use mechanical crushers. These machines are more efficient and help make wine cleaner and reduce the need for preservatives.

Crushing to Fermentation

The way grapes are crushed and handled depends on the type of wine being made:

• Red Wine: For reds, the grape skins, seeds, and sometimes stems are left in contact with the juice during fermentation. This imparts tannins, structure, and color to the wine, because tannins and color are found in the skins of the grapes.

• White Wine: White wines are typically pressed immediately after crushing to separate the juice from the skins and seeds. This prevents tannins from leaching into the must, ensuring a crisp, fruity wine without the drying sensation of tannins.

• Orange Wines: Made from white grapes but fermented with the skins (even white grape skins can impart color and tannins to a wine), orange wines often have a deeper color and bolder, more tannic flavors than typical whites. Despite the name, not all orange wines are literally orange in hue.

• Rosé: Created by limiting skin contact during fermentation, rosés are made from red grapes but processed more like white wines, resulting in their signature light pink color and fresh, fruity flavor.

Each decision at this stage (such as how much skin contact to allow, the type of crusher to use, and even the size of the fermentation vessel) affects the wine’s final flavor, body, and complexity.

Stage 5: Fermentation

Fermentation is the heart of winemaking, where the grape juice transforms into wine. This process is powered by yeast, which consumes the sugars in the grape must and converts them into alcohol, carbon dioxide (CO₂), and a host of complex flavors and aromas.

Fermentation begins when yeast (either wild or cultured) is introduced to the must. The yeast starts metabolizing sugar within hours, producing alcohol and CO₂ as byproducts.

During fermentation, winemakers closely track the sugar level (measured in Brix (US) or g/l (EU)) and temperature. As sugar levels drop, alcohol content rises, and managing temperature is critical. Warmer fermentation accelerates the process, while cooler temperatures preserve delicate flavors.

With red wine, CO₂ pushes grape skins and solids to the top of the fermentation tank, forming a "cap." To extract flavor and color, winemakers mix the tank multiple times daily through punch-down or pump-over.

Red vs. White Wine Fermentation

Sugar Level

Brix measures the sugar content in the must in the U.S., which helps winemakers predict alcohol levels and plan the fermentation process.

In the EU, sugar content in grape must is often measured using:

• Oechsle (°Oe): Common in Germany 

• Baumé (°Bé): Common in France 

• Typical ranges include:

If the sugar content (and potential alcohol level) is too low, winemakers may perform chaptalization — adding sugar (usually cane or beet sugar) to boost alcohol levels. This is common in cooler climates where grapes may not fully ripen before harvest. However, in some regions, this is not allowed.

What Kind of Yeast?

Wineries even have choices about the kinds of yeast they use.

• Wild Yeast: When ripe, wine grapes (as well as some other fruits) typically have a white powdery substance on them called “bloom”, which is particularly rich in yeast. While it can produce unique, complex flavors, it is also unpredictable (i.e., it may not be strong enough to finish the fermentation), so some winemakers prefer cultured yeast.

• Cultured Yeast: There are many commercial yeast strains (e.g., Saccharomyces cerevisiae) which can influence winemaking. Some strains thrive in high-sugar, high-alcohol conditions. Other strains bring out certain flavors in a wine.

Second Fermentation

Some wines go through a second fermentation process called malolactic fermentation (MLF). This phase converts malic acid (think green apples) into softer lactic acid (think butter).

MLF adds stability to the wine, reduces acidity, and imparts a noticeably creamy buttery texture in white wines. Most red wines undergo MLF for balance and texture. Some whites, like Chardonnay, may also undergo MLF to develop richer, more rounded flavors. However, for wines where bright acidity is desired (like Sauvignon Blanc or Riesling), MLF is avoided to preserve citrus and fresh fruit notes.

Stage 6: Storage / Clarification

Once fermentation is complete, the wine enters a stage known as élevage, where it is stored and clarified. This phase shapes the wine’s final character and prepares it for bottling. The wine can spend months, or even years in barrels or tanks, depending on the style and the winemaker's vision.

Storage Methods

There are two practical storage methods for élevage widely used today:

• Oak Barrels: Oak introduces distinct flavors and aromas, such as vanilla, spice, or toasted wood. The barrels also allow micro-oxygenation, which softens the wine’s tannins and enhances complexity. The type of oak (American, French, or Hungarian) and its age (new or used barrels) significantly affect the wine’s profile.

• Stainless Steel Tanks: Modern steel tanks offer a more controlled and reliable storage method. These tanks preserve the pure flavors of the wine without adding additional aromas or complexity. They are commonly used for white wines or lighter reds where freshness is key.

Élevage Influences

Winemakers can manipulate the wine in several ways during this phase to adjust flavors, aromas, and textures:

Bâtonnage (Stirring)

The lees (dead yeast cells and other solids) are stirred back into the wine. This process enhances texture, adds complexity, and introduces flavors like bread or cream. It can also increase oxygen exposure, which can soften the wine’s profile and develop unique aging characteristics. It is a winemaking technique primarily used in white wines and occasionally in certain sparkling and orange wines.

Racking

The process of transferring wine from one barrel (or tank) to another, leaving behind sediment, lees, and other unwanted solids that settle at the bottom during fermentation and aging. This technique serves several key purposes in winemaking: Clarification and Sediment Removal, Oxygen Management, Prevention of Off-Flavors, and Wine Stability.

• Red Wines: Typically racked 2–4 times during barrel aging.

• White Wines: Racking is less frequent, depending on the winemaker’s style (e.g., some whites may benefit from extended lees contact).

Topping

Is the practice of regularly adding wine to barrels during aging to replace the volume lost through evaporation and absorption. This process is critical for maintaining wine quality and preventing spoilage. Key Reasons for Topping Off Barrels: Prevent Oxidation, Prevent Microbial Spoilage, Compensate for Evaporation, Preserve Wine Integrity During Aging.

Clarification and Filtration

After storage, the wine is clarified to remove any remaining solids or unwanted particles:

Fining agents (like bentonite clay or egg whites) may be added to the wine to bind to particles, causing them to settle at the bottom for easier removal. This process improves the wine’s clarity and texture without altering its flavor. It is important to note that these fining agents do not remain in the wine.

Filtration removes tiny particles that may affect the wine’s appearance or stability to refine the product even further.

Note: that not all wines are filtered or fined; it is just another choice a winemaker has at their disposal. 

Stage 7: Bottling

Bottling marks the end of the winemaking process and the beginning of the wine’s journey to the consumer. While it is relatively straightforward, this stage is crucial for preserving the wine’s quality.

1. Minimizing Air Exposure: Air in the bottle can spoil the wine, leading to oxidation or of flavors. Careful bottling techniques can prevent this, preserving the wine’s intended flavors.

2. Bottle Design. Dark-colored bottles protect the wine from sunlight (which can degrade its taste over time).

3. Sealing Methods: Corks are traditional and environmentally friendly, creating a tight seal while allowing minimal oxygen exchange. Screw caps are often used for more affordable wines but can still provide an excellent seal.

From there, the wine is carefully labeled, boxed, and shipped — usually ready to be uncorked and enjoyed right away.

Winemaking Diagrams

Looking for a more visual explanation? Check out these illustrations.

How Red Wine is Made (Illustration)

How White Wine is Made (Illustration)

How Sparkling Wine is Made (Illustration)

There Is Much More To Learn About Wine

What makes wine truly special isn’t just the grapes or the processes employed. It’s the people and the decisions behind the winemaking, no matter what that involves.

Now that you know the steps that go into crafting a bottle of wine — from vineyard to fermentation to bottling — you can begin to appreciate the artistry and complexity in every sip. But knowing is only part of the journey. The real question is: Can you taste the differences?

At Napa Valley Wine Academy, we help you go beyond theory and develop a deep love for wine, beer, and spirits. Whether you’re a curious beginner or an experienced enthusiast, our courses will guide you through the world of wine with hands-on learning, tastings, and expert instruction.

Explore wine on a whole new level with in-person or online classes, and learn to identify the flavors and stories behind every glass.

Sign up for a WSET course or embark on a wine trip today!