Winemaking Basics: An Overview of the Winemaking Process

 

Winemaking embodies an intricate and time-intensive artistry. Comprising multiple stages, this meticulous process demands years of dedication before a bottle is deemed fit for sale. At every juncture of this journey, vintners are confronted with critical decisions that wield a profound influence on the ultimate character of the wine. The choices they make can render the wine sweet or dry, light, or bold, and contribute to the development of distinctive flavor profiles. But what exactly are these choices, and how does the magical transformation of grapes into wine occur?

Winemaking is an extensive and intricate procedure, encompassing a series of essential steps: from nurturing the growth of the vines to the harvest and crushing of the grapes, followed by fermentation of the wine must, aging, fining, and finally, the bottling of the precious liquid.

Throughout the entire winemaking journey, vintners face numerous opportunities to shape the outcome of the wine. Moreover, the approach to winemaking can significantly vary depending on the desired type of wine they wish to produce. In the following article, we will delve into each of these steps and explore the decisions vintners must undertake to craft a wine of utmost distinction."

Step 1: Growth

Step 2: Harvest

Step 3: Crush

Step 4: Fermentation

Step 5: Aging

Step 6: Fining

Step 7: Bottling

STEP 1: GROWTH

Cultivating the vines marks the inaugural step in the art of winemaking. Countless wine experts maintain that the vineyard itself is where the true essence of wine takes shape, for the decisions made by vintners during the growth of vines wield a pivotal influence on the ultimate quality of the wine.

Selecting Grape Varieties

The first crucial decision confronting vintners is the choice of grape varietal they wish to cultivate. Naturally, grapes exhibit variations in sweetness, acidity, and tannin levels. By carefully selecting a grape variety with the desired characteristics, winemakers lay the foundation for the type of wine they seek to produce. The compatibility of the grape with the local climate and terroir plays a vital role, as certain conditions may limit the number of varietals suitable for a specific vineyard. Factors such as heat resistance, frost tolerance, disease susceptibility, and pest resistance come into play. For instance, Cabernet Sauvignon grapes, with their robust, thick skins, boast remarkable resilience, while Pinot Grigio berries, with their delicate, thin skins, demand more care due to their vulnerability to diseases and temperature fluctuations.

Influence of Terroir on Wine:

The growth and vitality of the vines are largely influenced by the terroir, encompassing the quality of the soil and the topography of the land.

The soil quality determines the ease with which vines can develop their roots and absorb essential nutrients. While different grape varieties have specific needs, some general requirements for healthy vines include loose soil texture, effective drainage, and proper aeration.

The topography refers to the shape of the land, and many vintners prefer hilly terrains over flat landscapes for several reasons. Vines grown on slopes benefit from improved drainage, enhanced protection against frost and strong winds, and increased exposure to sunlight. Accordingly, winemakers in the Northern hemisphere, encompassing European countries, the United States, and Canada, often opt for south-facing hills, while their counterparts in Australia, New Zealand, South America, and South Africa favor north-facing slopes.

The Significance of Climate and Weather in Winemaking:

Climate exerts a profound impact on the characteristics of wine. Grapes cultivated in regions with high temperatures and abundant sunshine tend to ripen faster and achieve higher sugar levels. Consequently, vintners can produce sweeter wines or wines with elevated alcohol content (factors that will be discussed further during the fermentation process). Conversely, cooler climates lead to crisper wines with lighter body profiles. These differences are evident when comparing wines from New World wine countries like the United States or Australia to those from Old World wine regions in Europe.

In addition to the general climate, the weather in a given year can dramatically influence wine quality. Particularly in colder climates such as France or Germany, rainy summers or early winters may hinder grapes from fully ripening. Conversely, heatwaves can scorch the grapes and diminish their natural acidity. Natural disasters like storms or floods can also decimate an entire year's harvest.

Winemakers have limited options to mitigate the negative effects of weather conditions. They may adjust pruning practices, leaving more leaves on the vines to provide shade for the grapes and protect them from sunburn. Furthermore, adjusting the harvest date can offer more or less exposure to sunlight, or shield grapes from sudden cold snaps.

The Impact of Vines' Age on Wine Characteristics:

Unlike annual crops such as tomatoes or carrots, vines are perennial plants that can live for hundreds of years. There is a common belief that old vines produce lower yields and smaller grapes than younger vines, resulting in more concentrated aromas and superior wine quality. This belief is often attributed to the deeper roots of older vines, enabling them to access more nutrients.

However, empirical evidence does not consistently support this belief, at least in terms of output. A study from Australia in 2017 revealed that older vines may, in fact, produce higher yields due to their larger size. The precise impact of vines' age on wine quality remains a matter of debate, as quality is subjective and varies depending on individual preferences.

Watering Techniques for Vines:

Proper vine care encompasses various aspects, and watering is among the most critical factors. Providing the right amount of water is essential to promote the growth of healthy vines and grapes. During the budding and flowering stages, vines typically require more water, but as the grapes begin to ripen, vintners limit the watering to encourage the vines to prioritize grape growth over leaf production.

The necessity for artificial watering depends on the climate. In many New World countries with hot climates like Australia or South Africa, artificial irrigation is essential due to inadequate rainfall. However, in many prestigious wine regions in Europe, winemakers minimize watering to create higher-quality wines.

Pruning Branches and Leaves:

Pruning is another vital practice for maintaining vine health. This process involves trimming leaves and branches, and it is an essential aspect of producing high-quality wine.

An excessive number of branches on a vine can lead to nutrient shortages and improper grape ripening, resulting in subpar flavor development. By carefully removing certain branches, vintners compel the vines to channel their energy into the remaining canes, thereby reducing yield but producing grapes of better quality and flavor.

Pruning also involves the removal of rotten and diseased branches to ensure the overall health of the plants and prevent the spread of diseases to other vines. Timing is crucial, as early pruning risks damage from frost, while late pruning may negatively impact the next spring's blooming process. Therefore, late winter, as temperatures rise but before plants bloom, is typically the best time for pruning.

Additionally, vintners often perform a second pruning in late summer, focusing on removing leaves. During the summer months, leaves shield the grapes from sunburn. However, as the hottest period passes, a little extra sunlight exposure benefits the grapes in the weeks leading up to harvest, making late summer pruning advantageous.

Protecting Vines from Pests and Diseases:

Shielding vines from pests, diseases, and fungi is a critical aspect of vineyard management, as these threats can severely impact grape quality and potentially devastate an entire year's harvest. To safeguard against these dangers, winemakers employ various measures:

•  Insecticides are utilized to combat insects that pose a threat to vines, such as leafhoppers, mealybugs, and cicadas. These chemicals act as potent poisons, effectively killing harmful insects to protect the vineyard.
• Herbicides target weeds and parasitic plants that may compete with vines for essential resources like nutrients, water, and sunlight. Controlling these competing plants is particularly important for newly planted vine stocks with underdeveloped root systems.
• Fungicides are used to protect vines from fungal infections, such as powdery mildew, which can impair photosynthesis and hinder grape development. These chemicals aim to kill existing fungi or destroy spores before they can spread.
• Bactericides are employed to prevent bacterial infections that can impede water transportation, delay budding, and compromise nutrient absorption in vines, potentially leading to vine death.

Some vintners opt for biological measures, following organic or biodynamic winemaking practices, eschewing chemical agents to protect their plants. These alternative methods may involve planting specific flora near the vineyard to attract insects that feed on parasites and maintaining proper vine pruning to provide adequate aeration and reduce the risk of fungal infections. 

STEP 2: HARVEST

Upon reaching ripeness or an optimal level of ripeness, vintners embark on the harvest of the grapes. This pivotal stage involves collecting the grapes while preserving the integrity of the vines. While some winemakers utilize modern machinery for this task, the potential risk of damaging the grapes or vines prompts many to opt for the meticulous process of hand-picking. In certain regions, local wine laws even mandate manual harvesting.

The Timing of the Harvest:

Choosing the right moment for the harvest is of utmost importance. Depending on the desired type of wine, vintners may choose to harvest their grapes earlier or later in the year.

Grapes left on the vines for a longer duration attain higher levels of ripeness, accumulating more sugar while losing some of their acidity. As a result, winemakers seeking to produce crisp wines often opt for an early harvest. This is particularly common for white wines and lighter reds like Pinot Noir.

On the other hand, those aiming to craft fuller-bodied red wines allow the grapes to remain on the vines for an extended period to enhance sugar content. Grapes destined for dessert wines receive the longest duration on the vines. If a bottle label indicates "late harvest," it signifies one of these sweet wines.

Unique Winemaking Practices:

Some unconventional winemaking practices emerged from accidental occurrences. During the late medieval period, delayed harvest led to the development of grapes infected with noble rot. This fungus caused the grapes to dry out and shrivel, resulting in the production of incredibly sweet wines instead of being discarded. Similarly, ice wine was born from grapes freezing on the vines due to early winter onset. When pressed, these frozen grapes released only a small amount of juice, but it was highly concentrated in sugar, leading to the creation of fantastic dessert wines. Today, vintners intentionally let their grapes freeze to produce ice wines.

Grape Selection:

After the harvest, vintners undertake the crucial task of selecting the most suitable grapes for their wines. Damaged, rotten, unripe, or otherwise unsuitable grapes are carefully sorted out. Additionally, other plant materials, such as leaves and branches, are removed from the grape clusters.

Typically, this grape selection process is manual, especially for vintners striving to create high-quality wines. In certain European regions, manual sorting is even necessary to obtain specific quality labels for their wines.

While many modern wineries have adopted automated devices for grape selection, various methods are employed:

• Some machines sort grapes based on size, excluding those that are too small.
• Other devices sort grapes according to density, passing them through a liquid-filled container. Ripe grapes sink to the bottom, while unripe berries float and are sorted out.
• The latest technology involves taking electronic images of each grape, and an algorithm evaluates the appearance of the grapes to identify and remove unhealthy ones.

 

STEP 3: CRUSHING

Following grape selection, the subsequent step in the winemaking process is the crushing of
the grapes, a straightforward procedure where pressure is applied to the grapes to rupture their skins, thereby releasing their juice, now referred to as "must."

There are various methods for crushing grapes, with the historical approach involving stomping them with bare feet. Many winemakers in European countries continue to uphold this tradition, even incorporating it into traditional wine festivities such as the Madeira Wine Festival. However, modern vintners have the option of using machines, ranging from old-fashioned mechanical crushers to advanced engine-driven technologies.

Grape solids play a pivotal role in determining the wine's color, and depending on the type of wine desired, winemakers may need to remove these solids from the must. Surprisingly, this applies to both red and white grapes:

• For red wines, winemakers allow the solids to remain inside the fermentation container, as they contribute to the red coloration of the wine.
• In the case of white wines, the solids are removed from the must to achieve a pale yellowish hue.
• Rosé wines are distinct; they retain the grape solids, but only for a limited period, resulting in a lighter pinkish color compared to typical red wines.
• Another unique variety is orange wine, made from white grapes. Unlike white wine, orange wine stays in contact with the grape solids for a certain duration, yielding an orange or amber-colored final product.

 

STEP 4: FERMENTATION

Undoubtedly, fermentation stands as the most pivotal phase in the winemaking process, where grape juice undergoes a magical transformation into wine.

To initiate this transformative journey, vintners transfer the crushed grapes into a fermentation container and introduce yeast to the must. These microscopic single-celled fungi play vital roles not only in winemaking but also in beer and bread production. As they feast on the grape sugars, yeast converts them into alcohol while concurrently producing carbon dioxide, essential for crafting sparkling wine.

Throughout fermentation, various chemical processes occur, bestowing distinctive characteristics upon the wine:

• Ester molecules, previously bound to grape sugars, are liberated, infusing the wine with fruity and floral aromas.
• The yeast also produces low levels of sulfites, which safeguard the wine from spoilage.
• Anthocyanins, responsible for coloration, impart their hue to the wine. To achieve this, vintners must refrain from removing grape solids.
• Alcohol, a byproduct of fermentation, enhances the extraction of tannins from the grape solids, adding bitterness and a puckering mouthfeel to the wine.

Temperature control plays a crucial role during fermentation, significantly influencing the
wine's profile. Higher temperatures accelerate tannin extraction, resulting in more tannic wines—typically preferred for many reds, fermented at temperatures between 70 and 80°F (21-27°C). Conversely, white wines are usually fermented at temperatures of about 45 to 60°F (7-15°C) to promote the development of fruity aromas. Monitoring the containers closely is vital as fermentation generates heat—an exothermic process. Measures are taken to regulate the temperature to avoid yeast cell death from excessive heat or sluggish fermentation from excessively low temperatures.

Fermentation occurs in two stages: "primary fermentation" or "aerobic fermentation" for about a week, where yeast cells rapidly multiply, requiring oxygen in the vessel. Subsequently, "secondary fermentation" or "anaerobic fermentation" follows, lasting one to two weeks, with reduced oxygen to shift yeast focus to converting sugar into alcohol. The fermentation slows down as sugar consumption progresses, eventually stopping naturally to yield a dry wine. To create sweet wines, vintners halt the process artificially by either lowering the temperature to impede yeast sugar consumption, raising it to kill the yeast, or adding strong alcohol like Brandy to stop fermentation in fortified wines.

The choice of fermentation vessels impacts secondary fermentation, with containers allowing varying degrees of oxygen exposure altering wine characteristics. Common vessel types include:

• Oak wood containers permit some oxygen contact, softening tannins and acidity for a more balanced wine.
• Stainless steel tanks are airtight, preventing oxidation to preserve the original crisp and fresh characteristics of the wine.
• Concrete vessels allow minimal oxidation, imparting mineral aromas to the wine.
• Clay containers permit slight oxygen exchange, adding subtle earthy notes to the wine while maintaining a generally neutral influence.

STEP 5: AGING

Following successful fermentation, some vintners choose to age their wine, a process intended to develop more delicate flavors and achieve better balance, akin to seasoning. This aging leads to chemical transformations over time, with oxygen playing a vital role. Similar to fermentation, winemakers intentionally expose their wine to some air during aging.

Aging is not an obligatory step in winemaking, and certain wines may not be suitable for aging at all. However, laws in some European wine regions mandate vintners to age their wines to earn specific quality labels. Generally, red wines, especially those with high tannin levels and a full body, undergo the aging process, whereas it is less common for white wines. Nevertheless, some bolder whites, such as Chardonnay or Sauvignon Blanc from New World wine countries, may also undergo aging.

“Oaking” or Oak Aging

The most prevalent method of aging wine is through oaking. Vintners transfer their wines into oak barrels, allowing them to mature over an extended period, often spanning multiple years. As oakwood is not entirely airtight, oxygen seeps into the barrels, initiating chemical processes that significantly alter the wine's characteristics. The key effects of oaking include:

1.      Imparting tannins to the wine, making it more tannic than unoaked wine.

2.      Softening aggressive tannins, leading to a smoother texture.

3.      Introducing new aromas such as vanilla, dried fruits, tobacco, coffee, or spices.

4.      Concentrating flavors through evaporation, intensifying the wine's overall taste.

5.      Enhancing the wine's color, making it more intense.

“Tanking” or Tank Aging

The specific effects depend on the barrel size, type, and age of oak used. An alternative to oaking is tank aging in stainless steel tanks, which are easy to clean and allow bulk aging. Unlike oak barrels, they don't impart new flavors or significantly soften the wine, making them ideal for producing light and crisp wines, particularly white wine and sparkling wine.

Bottle Aging

Another aging method is bottle aging, where vintners mature their wine in glass bottles. This method offers advantages, such as faster aging and more control, but it does not infuse new flavors or allow much oxygen exchange, resulting in less significant changes compared to oak aging. Bottle aging is a standard practice for sparkling wine producers, especially for prestigious varieties like Champagne or Franciacorta. In some cases, vintners may use both oaking and bottle aging consecutively to optimize the wine's flavors.

 

STEP 6: FINING

One of the final steps in winemaking is the fining stage, primarily aimed at optimizing the wine's taste, but it also serves other purposes. Fining involves the use of specific agents to achieve the following effects:

• Soften the wine's tannins and reduce bitterness.
• Filter out solid particles and sediments, resulting in a clearer appearance.
•  Adjust the wine's color.

Fining agents interact with the wine, either chemically or physically, to bind and capture unwanted materials. These agents then settle to the bottom of the container, allowing vintners to easily remove them.

Various materials are used as fining agents, including animal-derived, plant-based, and mineral substances. The most common fining agents are as follows:

• Gelatine: Derived from the skins and bones of cattle and pork, gelatine softens tannins, reduces bitterness, and clarifies the wine.
  
• Casein: A protein from cow's milk, used to clarify and stabilize the wine by preventing over-oxidation.
  
• Egg whites: Obtained from hens' eggs, egg whites are used to soften tannins.
  
• Isinglass: Derived from fish swim bladders, isinglass clarifies the wine and intensifies its color.
  
• Bentonite: A special type of clay that filters out other protein-based fining agents after their job is done.
  
• Silica gel: A porous form of silicon dioxide that aids in filtering out dead yeast cells.
  
• Charcoal: Used to reduce off-flavors and color intensity.

While the application of fining agents is common in traditional winemaking, some vintners following organic, biodynamic, or natural winemaking approaches choose not to use some or all of these agents. Additionally, some fining agents are derived from animal sources, making them unsuitable for vegan winemaking.

STEP 7: BOTTLING

The final step in winemaking involves transferring the wine into bottles, a process that is now efficiently carried out using automated bottling lines. However, before the wine is ready for sale, the vintner must make important decisions that can significantly impact its quality. Key considerations include the type of packaging and sealing to use, as well as measures to preserve the wine.

Bottle Material:

Glass is the most common material used for wine containers, and for good reason. It is leakproof, airtight, and neutral in smell, making it an excellent choice for storing wine. While its fragility is a drawback, the benefits of using glass outweigh this aspect. The color of the glass also plays a vital role in wine preservation. Green or brown glass acts like sunglasses, shielding the wine from harmful light. For wines intended for long-term aging, vintners rely on these colored glass types. Some producers, like those of Port wine, even opt for black glass to provide extra protection. Light wines, meant for early consumption, often come in colorless bottles, as they do not require extensive protection from light exposure.

Plastic packaging is common for cheaper wines and comes in boxes with larger volumes compared to glass bottles. Despite some criticism from wine enthusiasts, plastic packages do not necessarily indicate inferior wines.

Adding Preservatives:

In traditional winemaking, measures are taken to preserve the wine in the bottle. One common action is removing air to prevent undesired oxidation. Vintners can flush the bottle with carbon dioxide or nitrogen before filling it with wine for this purpose. Another standard measure is the addition of sulfites. Sulfites help stabilize the wine by preventing unwanted fermentation and preserving its freshness. While sulfites naturally occur during fermentation in small volumes, vintners may add more before sealing their bottles to extend the wine's shelf life. However, due to sulfites potentially causing issues for individuals with allergies, some winemakers opt not to add them artificially, particularly in the case of producing organic wines.

Bottle Seals:

The vintner also has to decide on the bottle sealing method. The traditional approach involves using a cork, which is ideal for wines with aging potential as it allows minimal airflow. Over time, this controlled exposure to oxygen can enhance the wine's qualities. However, corks have some disadvantages, as they can dry out, become porous, and break easily. In the worst-case scenario, cork pieces may fall into the wine, ruining it. Corks are also susceptible to taint, which imparts unpleasant aromas to the wine.

To address these concerns, winemakers have developed alternative bottle seals. Light wines without aging potential are often sealed with screw caps. These stoppers are airtight, stable, immune to taint, and easier to open than corks. Another option is synthetic cork, which allows some aeration while being more reliable and cost-effective than natural cork.

 

CONCLUSION

Winemaking is an intricate and patient process that demands profound knowledge and skill. Crafting exceptional wine can span years, and in some cases, even decades. After learning about the various stages and decisions involved in winemaking from this article, you can now comprehend the reasons behind this time-consuming endeavor. It's no wonder that wine enthusiasts hold great wine in such high regard, given the dedication and artistry required to produce it.