This informative article, prepared by the Infowine editorial team, is based on the webinar “Dealcoholization: State of the Art and Effects on Wine Quality” presented by Professor Maria Tiziana Lisanti from the University of Naples Federico II.
For more details, it is recommended to view the original video, which can be accessed by subscribing to Infowine Premium.

The growing trend toward a healthier and more conscious lifestyle is influencing the wine sector, driving research and industry efforts toward the production of low-alcohol or even alcohol-free wines. However, wine dealcoholization represents a complex technical challenge with significant impacts on the sensory characteristics and stability of the final product.
In this article, we explore various dealcoholization techniques, their effects on wine quality, and the associated challenges, drawing from the latest research and practical experiences in the field of enology.

What is Wine Dealcoholization?

Dealcoholization is a process that removes alcohol from wine using specific techniques. The goal can be to produce wines with a moderate alcohol content (10-12% ABV) or to eliminate alcohol completely or almost entirely, creating the so-called NoLo wines (“no” and “low” alcohol). This process is complex, as it impacts not only the alcohol content but also the organoleptic characteristics, stability, and very identity of the wine.

The Role of Alcohol in Wine Quality

Alcohol plays a fundamental role in wine, contributing to its body, mouthfeel, and perception of warmth, as well as influencing its aroma, flavor, and overall structure. Any variation in alcohol content affects both the quantitative and qualitative aspects of the wine. Achieving a good balance between the desired alcohol level and preserving organoleptic quality requires a deep understanding of enological processes.

Causes of the Increase in Wine Alcohol Content

In recent decades, the alcohol content of wine has increased globally, with average rises of 0.2 to 1.3 alcohol degrees. This phenomenon is primarily linked to factors associated with climate change.

Climate Change and Vine Phenology

1. Accelerated Ripening: Higher temperatures speed up grape ripening, resulting in higher sugar content and, consequently, elevated alcohol levels after fermentation.
2. Risk of Quality Compromise: While early harvesting can reduce alcohol levels, it often produces wines with less aromatic complexity and quality, diminishing their market appeal.
3. Consumer Preferences: Despite higher alcohol levels, today’s consumers seek wines with lower alcohol content, aligning with trends toward healthier lifestyles. This contrast highlights the importance of finding solutions that balance alcohol content with sensory characteristics.

Factors Influencing the Demand for Low-Alcohol Wines

The demand for low-alcohol wines is driven by several factors:
• Health Awareness: Increased attention to the effects of alcohol on health has heightened interest in lighter wines.
• Calorie Control: The caloric intake from alcohol has become a significant consideration for health-conscious consumers.
• Consumption Flexibility: Low-alcohol wines allow consumers to enjoy wine without the effects of alcohol, making them suitable for occasions like business lunches or casual gatherings.

Wine Dealcoholization Techniques: Approaches and Innovations

Dealcoholization can be achieved through various techniques, each with its own advantages, limitations, and impacts on wine quality. These methods fall into two main categories: distillation techniques and membrane-based techniques.

Distillation Techniques (Vacuum Distillation)

Distillation methods separate ethanol from wine by exploiting the differing boiling points of ethanol and water. To minimize thermal impact, this distillation is conducted under vacuum, lowering ethanol’s boiling point to around 40°C.
• Spinning Cone Column (SCC): This is the most widely used technique in enology today. Inside the column, there are fixed and rotating steel cones. As wine descends through the column, its rotation forms a thin layer on the cones’ surface, allowing ethanol to be efficiently distilled at low temperatures and relatively quickly.
Another key feature is its ability to recover the aromatic fraction, which contains ethanol and most volatile molecules. This fraction is distilled at about 30°C, reserved, and reintroduced into the dealcoholized wine. This method preserves the aromas that other techniques often lose along with the ethanol.

Membrane-Based Techniques

These techniques use porous, semipermeable membranes to separate ethanol from wine. The membranes perform molecular-level filtration, separating molecules into distinct fractions. Despite efforts to make the process highly selective for ethanol, some wine molecules, including volatile compounds, can also pass through the membranes.
• Reverse Osmosis (RO) and Nanofiltration: In these methods, ethanol passes through the membrane under applied pressure. The process requires subsequent distillation of the separated water-ethanol mixture, which is later reintroduced into the filtered wine.
• Membrane Contactor: Transfer occurs due to a concentration difference—in this case, ethanol—between the wine and an extracting fluid flowing on the other side of the membrane. Membrane contactors are highly efficient at preserving aromatic compounds and are energy-efficient.

Advantages and Disadvantages of Dealcoholization Techniques

Each dealcoholization method has specific benefits and limitations, influencing the choice of technique depending on the type of wine, the desired alcohol reduction level, and quality goals.

Advantages
1. Precise Alcohol Level Control: Dealcoholization techniques allow producers to achieve specific alcohol levels, providing greater flexibility.
2. Versatility: These techniques can be adapted for various wine types, including reds, whites, and sparkling wines, making dealcoholization applicable across multiple varieties.

Disadvantages
1. Loss of Volatile Aromas: Both distillation and membrane techniques cause a loss of esters, terpenes, and other volatile compounds responsible for fruity and floral aromas, reducing the wine’s sensory appeal.
2. Sensory Profile Alteration: Dealcoholization changes the balance of sweetness, acidity, and body. Lower alcohol content often increases the perception of acidity and astringency, affecting the wine’s overall structure.
3. Microbiological Stability: Ethanol naturally contributes to the microbiological stability of wine. Reducing alcohol content increases the risk of contamination by yeasts and bacteria, posing significant challenges for long-term product stability.

Effects of Alcohol Content on the Sensory Profile of Wine

Alcohol content significantly impacts the sensory characteristics of wine, influencing its flavor, aroma, mouthfeel, and overall drinkability.

Changes in Flavor and Mouthfeel

• Bitterness and Sweetness: Alcohol contributes to the perception of bitterness, sweetness, and body in wine. When alcohol levels are reduced, wines tend to be more acidic and less sweet, diminishing their roundness and balance on the palate.
• Astringency and Acidity: Lower alcohol levels make astringency and acidity more pronounced, especially in red wines, where tannins play a critical role. This shift can render dealcoholized wines less balanced and more aggressive.

Aromatic Impact

Alcohol content affects the volatility of aromatic compounds. Generally, alcohol suppresses the aroma of most volatile molecules in wine, such as fruity and floral notes, while enhancing the volatility and perception of herbaceous aromas or compounds like linalool and 3-mercapto-1-hexanol.

Research Findings: Studies on the Effects of Dealcoholization

Reducing alcohol concentration always results in a proportional loss of volatile compounds. Esters, which are responsible for fruity aromas, are primarily lost, eventually leading to the complete absence of volatile molecules. These sensory profile changes are not only due to the loss of volatile compounds but also to the removal of ethanol. Conversely, basic chemical parameters (acidity, sugars, pH, and the polyphenolic fraction) remain unchanged or are only slightly affected.

Studies on the effects of dealcoholization in red and white wines indicate that reductions of up to 20% of the original alcohol content do not cause significant quality loss. However, greater reductions lead to noticeable changes in aroma and flavor, particularly in red wines. Sensory analyses, including triangular tests with trained panels, confirm these findings, showing that wines dealcoholized up to 20% remain acceptable to consumers, while more substantial reductions can negatively impact their appeal.

Challenges and Opportunities in the Production of Low-Alcohol Wines

The growing demand for low-alcohol wines represents an opportunity for innovation but also introduces several challenges. As dealcoholization technologies evolve, it is increasingly important to preserve wine quality and ensure sustainable production.

Key Challenges

1. Preserving Organoleptic Qualities: Current techniques have limited capacity to maintain the sensory profile of wine, particularly delicate aromas.
2. Microbiological Stability: Alcohol acts as a preservative in wine, protecting it from microbiological spoilage. Low-alcohol wines are more susceptible to contamination by microorganisms.
3. Regulatory and Labeling Aspects: Various regulations define and govern dealcoholized wines across different countries. Compliance is essential for market access but can limit production flexibility.

Opportunities for the Future

1. Demand for Healthier Products: Increasing interest in wellness and health offers significant opportunities for NoLo (no or low-alcohol) wines.
2. Technological Advances: Research into new membrane materials and improved process parameters holds promise for better aroma retention and reduced quality loss.
3. Sustainability in the Process: Developing dealcoholization methods with lower water and energy consumption can make these techniques more sustainable, addressing consumer concerns about environmental impact.

Conclusions

Integrated Strategies for Effective Dealcoholization

As dealcoholization techniques improve, an integrated approach becomes increasingly necessary to produce high-quality low-alcohol wines. Combining vineyard management with targeted dealcoholization can help achieve optimal results while minimizing sensory impact.

Strategic Approaches to Dealcoholization

1. Vineyard-Level Regulation: Techniques like early harvest, vegetation management, and selecting specific rootstocks can reduce sugar levels in grapes, leading to lower alcohol content in wine.
2. Fermentation Management: Selecting yeast strains that produce less alcohol and adjusting fermentation conditions can further aid in controlling alcohol production.
3. Selective Dealcoholization: Applying selective dealcoholization to wines targeted for moderate alcohol reduction helps maintain a more balanced sensory profile, particularly in wines where total dealcoholization is not feasible.

Navigating the NoLo Wine Market

The NoLo wine market is an exciting frontier, but achieving a balance between consumer expectations and product quality remains a challenge. Partial dealcoholization has proven effective for producing low-alcohol wines with minimal sensory alterations. However, producing completely alcohol-free wines requires further innovation.
Dealcoholization also necessitates a reassessment of wine stability and microbiological safety, as the absence of alcohol increases spoilage risks. Ultimately, advances in technology, research, and regulatory frameworks will play a crucial role in effectively integrating NoLo wines into production lines.

For a more in-depth analysis of this topic, including specific experimental data and process details, we invite readers to watch the full webinar recording, which provides a comprehensive guide to the science and practice of wine dealcoholization.