Opportunities and Challenges for Low-Alcohol Wine

Abstract

For centuries, diverse societies worldwide have fermented grapes and other raw materials to produce wine, elevating winemaking to an esteemed art form in numerous cultures and religions. Over time, globalization homogenized wine production, yielding a conventional approach known as traditional wine production. Recently, research on the adverse effects of alcohol consumption has spurred a trend toward low-alcohol wine, typically containing less than 8.5% alcohol by volume. This caters to health-conscious consumers and presents an economic opportunity for winemakers in an emerging market. Climate change has also impacted wine-grape cultivation, resulting in alterations of fruit quality and sugar accumulation. To address these challenges, viticulture practices are employed to mitigate photosynthetic product accumulation. Post-harvest, winemakers have various methods at their disposal to reduce alcohol content and maintain flavor balance. Producing low-alcohol wine poses challenges, including the risk of unwanted microbes and the need for vigilant monitoring during aging to prevent oxidation and spoilage. Despite the industry’s millennia-old history, there remains ample room for innovation in low-alcohol winemaking. With shifting consumer preferences and climate change, the demand for lower-alcohol wines is poised to grow, necessitating ongoing research and innovative practices to create well-balanced wines that align with evolving consumer tastes and environmental conditions.

1. Introduction

With a long-recorded history, relics show humans have created and revered wine for thousands of years. Since the Neolithic period, humanity has intentionally created wine, with evidence of resinated wine products found in northern Iran dated to 5400–5000 BCE [1]. These wines were stored in resinated containers to take advantage of tree sap’s preservation properties allowing for longer storage and less ullage. This practice continues today with retsina wine made in Greece [2, 3]. Wine can be traced back to many ancient civilizations including the Egyptians, Greeks, Romans, and Mesopotamians with notable social significance placed on the beverage. Around 3150 BCE, King Scorpion I of ancient Egypt prized wine for its status and ostentation and was buried with nearly 4500 liters filling three chambers from floor to ceiling [4]. Throughout history, wine has constituted significant cultural and religious importance from Romans toasting for good health before voyages to modern-day Catholic communion with wine signifying the blood of Christ [5]. The mix between the art and science of winemaking developed alongside wine’s cultural and religious prevalence.

Over time and alongside trade globalization, government-imposed taxes were levied on the sale and consumption of many alcoholic beverages and influenced winemaking practices. These tariffs are known as alcohol excise taxes and can vary based on the product classification. For example, in many European countries, wine products do not have any alcohol excise tax, although other alcoholic products even lower in alcohol content might [6]. There are also differences in taxation based on the type of product made, such as premium or sparkling wine having much higher taxes on average [7]. The alcohol content is also a significant factor in the wine trade as wines produced with lower alcohol by volume (ABV) fall into lower tax brackets and are thus more marketable to the consumer [8]. To remain within the ABV threshold, the wine may need to be adjusted to decrease the alcohol content with vineyard management, pre-fermentation, and/or post-fermentation practices. As such, with alcohol tax and maximizing revenue, many wines produced with similar methodology and alcohol content can be called “traditional” wine. In general, wine has become more alcoholic due to increased global temperatures and sugar accumulation, so more production interventions or lobbying efforts usually follow to maximize profitability while aligning with legal limitations [9]. There is an economic disincentive to producing wines with higher alcohol content.

Historically, the production of wine has changed over many years and regions. In the modern era, the speed of global transformation is unprecedented, and the industry must adapt to capture customer wants and to create production efficiencies. Different market niches and important terroir changes make the development of new wine practices a desired venture for the wine industry. A modern trend has arisen from research into the negative effects of alcohol consumption, with a more informed consumer base preferring wine with less alcohol. Low-alcohol wine, classified by the International Organization of Vine and Wine (OIV) as consisting of between 8.5% and 0.5% ABV, presents a new niche of consumers who are more health-conscious and/or hoping to gain benefits from wine consumption while minimizing alcohol consumption [10]. For beverages with less than 0.5% ABV, they can be labeled as non-alcoholic and are considered soft drinks. With these consumer preference changes comes an economic opportunity for winemakers to capitalize on the underdeveloped market of low-alcohol wine.

2. Modern-day trends and a health-conscious society

In more recent years, there has been a significant increase in consumer preference of toward low-alcohol wine, marking a notable trend in the wine industry. Consumer demand has changed as the population becomes more health-conscious and mindful towards consuming alcoholic beverages. More and more of the drinking age demographic are looking for alternatives to traditional wines with higher alcohol content [11]. While options of dealcoholized wine are available in the market, the taste profile of the wine may be very different from traditional wine and can deter regular drinkers from choosing this alternative [12]. Low-alcohol wine offers a lighter and more restrained drinking experience while maintaining the unique flavors and characteristics associated with wine [13]. This emerging trend reflects an increasing demand for alcoholic beverages aligned with wellness and moderation and opens a new niche for exploration from winemakers and wine drinkers alike in low-alcohol wine.

While wine is often associated with the negative health factors associated with alcohol consumption, low-alcohol wine may be beneficial in subtly decreasing the drawbacks by creating a healthier alternative. Multiple health institutes, such as the American Institute for Cancer Research (AICR) and the World Health Organization (WHO), correlate many health conditions with alcohol consumption [14]. The WHO considers decreasing alcohol drinking as a necessary public health initiative to combat the prevalence of alcohol-related cancers and the strain placed on the health institutes to combat these preventable diseases [15]. A study identified the causation effect alcohol consumption has on cardiovascular disease, stroke, and peripheral artery disease [16]. Current media and marketing campaigns emphasize alcohol beverages that have a lower cost for inebriation, this would be the opposite situation for low-alcohol wines [17]. Some negative aspects of traditional wine’s alcohol content can be better managed if production and consumption of low-alcohol wine increases.

While alcohol is a major deterrent of consuming wine, the rich flavors and potential health benefits can highlight the positive effects of drinking a low-alcohol alternative. The French Paradox is a term used to describe the seemingly contradictory effects between the high-fat French diet and the relatively low incidence of cardiovascular disease among the French population [17]. Wine, particularly red wine, is viewed as one of the key factors contributing to this phenomenon. Red wine contains polyphenols, notably resveratrol, which possess antioxidant properties that can potentially reduce the risk of heart disease by protecting against oxidative stress and inflammation [18]. As a marketing strategy, wines that are lower in alcohol, thus the natural health benefits become more highlighted, can encourage a more health-conscious target audience to this functional food. Functional foods are scientifically demonstrated to have favorable effects on specific bodily functions, surpassing basic nutritional benefits, and contribute to an overall improvement in health, well-being, and disease risk reduction. A survey taken to determine if there is a market for functional wines (enhanced with resveratrol) showed the trend toward wellness products has an untapped potential in the wine industry from lower-alcohol wines [18].

2.1 “Healthy” choice: a double-edged sword

Low-alcohol wine has both an advantage and a disadvantage on the average consumer’s perception of the product. While low-alcohol wine has the benefit of hopefully decreasing the alcohol consumption of the wine drinker, there have been studies that indicate the perceived “healthiness” of the product may encourage greater imbibing. This phenomenon can be attributed to a psychological aspect of societal perception and the desire for a more guilt-free drinking experience. When individuals believe a wine is lower in alcohol, they may consider it the healthier choice and therefore can indulge in greater quantities [19]. Similar to other “healthy” food alternatives, the perception creates a feeling of permission, as drinkers believe they can enjoy greater quantities of wine without the consequences of higher alcohol intake [20].

With product advertisement playing an influential role in profitability, how low-alcohol wine is labeled and marketed can be a greater risk for alcohol overconsumption if done improperly. With a broad range of alcohol contents that can fall into the category of “low-alcohol” wines, it is important to maintain the message that moderation is important for responsible drinking habits. The industry will need to cautiously market low-alcohol wine to gain a consumer base of health-cognizant drinkers, while not spreading the false message that low-alcohol wine can be consumed to no health detriment.

3. Climate change

The environment in which wine grapes grow is an important factor on the quality of wine that can be produced. The term “terroir” is used to describe the phenomenon of a flavor profile imbued onto the wine product from the soil, climate, vineyards’ physical characteristics, and human management [21]. As the terroir of regions changes, so must the vineyard management practices and enological methods used to achieve optimal quality wine. The previously accepted measurements and classifications of winegrowing regions have become outdated with global temperature changes and water scarcity issues.

Climate change and recent global temperature increases have had a noticeable impact on grape quality and wine alcohol content. When contextualizing the issues faced by winegrowing regions, it becomes difficult to use water status to compare regions when water availability may differ from vineyard to vineyard. For this reason, temperature is the measurement more easily studied to determine which potential management practices to implement on a larger, regional scale. At temperatures above 35°C, the vines’ photosynthetic pathways and gas exchange shut down to conserve water and energy when the plants are in prolonged high stress conditions [22]. In Carignane, Pinot Noir, Cabernet Sauvignon, and Tokay, temperatures from 32.5 to 40°C caused decreases in ovule fertility, berry weight, shoot growth, berry size, and berry cell count [23]. These high heat conditions worsen the quantity of berries and the volume of wine that can be produced. Another issue currently affecting excessively warm regions is the shutdown of the grapevines for long periods of time causing arrested phenolic and carbohydrate development. Besides the berries’ external detriment in high heats, e.g. sun burn and shriveling, heat waves can decrease sugar accumulation of the berries so severe the grapes are not able to reach the desired dissolved sugar content (°Brix) [24]. There are few options available to the grape growers or wine producers when this occurs, and wine made from these grapes would be of poorer quality than desired. Lower sugar content would also produce lower-alcohol wine so these lower °Brix harvests may have to be mixed into another batch.

While excessive temperature increases cause decreases in vine metabolism and berry quality, moderate increases in temperature stimulate photosynthesis causing rapid sugar accumulation. This increase in sugar content translates to wine produced having higher alcohol content. Winemakers track the progress of the grape sugar content as a measurement of the juice °Brix to track the must weight and coordinate with the expected wine alcohol content [25]. When wine grapes are not properly tracked, overripe fruit tend to produce higher alcohol as the yeast has more sugar to digest, producing more ethanol [26].

A previous method of determining which grape varietals were suitable for regions was to calculate the growing degree days of the area and reference the Winkler Index [27]. The Winkler Index was a widely used scale with a baseline of 10°C developed by A. J. Winkler and M. A. Amerine to measure heat summation and correlate compatible grape cultivars with five classifications [28]. While the five categories (1 is little heat summation and 5 has the greatest) were relevant in the early 1900s, when the index was developed, current winegrowing regions have steadily gotten warmer and now surpass the upper limit of the Winkler Index. Previous compatible cultivars in set locations will have to shift toward areas with lower assigned Winkler Index values. For instance, regions where the Winkler Index previously classified certain varieties as too cold are now or will become warmer, thus the varieties could successfully be grown there [29]. The opposite also occurs where regions that had mild heat summation will no longer be able to sustain varieties not heat tolerant. A limitation of this scale is the narrow classification solely based on regions’ temperatures. An ever-growing issue for wine-grape growers is water availability as natural water sources get diverted to support the growing human population and must be considered alongside climate. Temperature alone is not enough to classify which regions and grape varieties are compatible to achieve the greatest quality wine. The Winkler Index is an outdated scale to categorize winegrowing regions and should be updated to reflect the current and future conditions created by climate change.

The traditional method of assessing wine-grape suitability via the Winkler Index and the timeline of berry maturity previously followed has become less relevant with the impact of climate change. Winemakers and growers must work together to track sugar accumulation and develop management strategies to coordinate the best quality wine with optimal alcohol content.

4. Viticulture and enological practices for low-alcohol wine

4.1 Viticulture

The deliberate production of low-alcohol wine begins in the vineyards to decrease the fermentable sugars present in the grape must at harvest. Multiple management strategies can be utilized to reduce the total carbohydrates produced by the vines or to dilute the produced sugars per volume via increased yield.

An initial management strategy to decrease wine alcohol content is the selection of the grape variety and rootstock which maximizes fruit production. While certain cultivars are selected based on market preferences, other scion and rootstock varieties that have a lower sugar accumulation may be used for blending or specialty wines when developing low-alcohol alternatives [30]. These determinations must be made during vineyard planning with expectations of higher temperatures potentially increasing the popularity of these varieties. As climate change affects winegrowing regions and the compatible varieties, planting choices will change and evolve to take advantage of these new opportunities.

Certain vineyard management practices, such as increasing vigor or reducing photosynthetic ability of the vine, can also decrease the must weight. Maximizing vigor via enhancing bud load, lowering cluster thinning, and greater irrigation can help to increase the total yield and dilute the sugar content spread across the fruit [31]. Removal of the leaves, which produce the carbohydrates through their photosynthetic pathways, can also decrease the amount of fermentable sugars at harvest. Slowing down the carbohydrate concentration and delaying ripening can be done by canopy defoliation or trimming shoots [32]. In a field experiment testing mechanical defoliation, the leaf removal reduced ripening by 2 weeks and allowed greater phenolic development without the competition of sugar accumulation [33]. In the sensory evaluation conducted from this study’s grapes, the wine was still considered well balanced and this may be from the decreased alcohol content being offset in flavor by the greater phenolics. Another method of reducing photosynthesis, while also being increasing drought tolerance, is the application of antitranspirants to the foliage and creating a thin, film barrier [34]. Vineyard management is the most important pre-harvest practice that can be implemented to produce lower-alcohol wine.

The final grape growing strategy used to decrease alcohol concentration is timing of the grape harvest. While it may seem that harvesting earlier would have a negative impact on the flavor profile due to reduced phenolic accumulation the differences are not enough to impact consumer preferences. In a sensory panel study, an early and late harvest was done on Cabernet Sauvignon, fermented separately, and the sensory panel found differences in the flavor profiles but no differences in likeability [35]. Multiple metrics are measured over time to track the ripening of the grapes and maximize quality, including the must titratable acidity (TA), pH, and °Brix. Early harvesting can also help blend wines of different phenolic and alcohol concentrations to produce lower-alcohol wines while maintaining a high-quality flavor profile. Additionally, harvesting earlier can reduce the strain on winery resources by fermenting smaller batches over a longer harvest period. Harvest timing can make a large impact on the wine’s quality, quantity, and alcohol concentration.

Scion and rootstock selection is a decision that may affect the marketability of the vineyard for many years, so the decision to choose high vigor varieties that produce less alcoholic wines may see increased demand. The vineyard management strategies from bud break to final sugar accumulation play a large role in the preparation of the harvest for low-alcohol wine production. These practices must be skillfully executed to maintain the greatest wine flavor profile while reducing fermentable sugars. The last decision made in the vineyard is timing of the harvest, which is very influential on the must weight and subsequent wine production. These viticulture practices used individually or in combination can help to prepare the grapes for production of low-alcohol wine (Table 1).

Method	Practice	Impact
Cultivar and vineyard planning	Scion/rootstock selection	Lower sugar accumulation; Increased vigor; Greater drought tolerance
Increasing vigor	Enhancing bud load; Lower cluster thinning; Increased irrigation	Increasing vigor; Diluting present sugars
Reducing photosynthesis	Canopy defoliation; Shoot trimming; Foliar antitranspirants	Lower sugar accumulation; Greater drought tolerance
Harvest timing	Measuring grape sugar and acidity	Maximizing flavor profile while avoiding excess sugar accumulation (TA, pH, °Brix)

Table 1.

Viticulture practices to produce low-alcohol wine.

4.2 Enology

4.2.1 Fermentation

After the harvest and preparation of the grape must, selection of enological practices can impact alcohol concentration in the final wine product. Two significant decisions that must be made regarding fermentation are the selection of yeast and manipulation of fermentation kinetics. Greater research into novel yeast options must be conducted to best suit the production of low-alcohol wine.

Whereas centuries of yeast culture isolation and traditional winemaking practices have mostly selected for a single yeast species, the development of low-alcohol wine may not be conducive to simply changing the usage or the genetic potential of Saccharomyces cerevisiae. While a staple in any enologist’s yeast selection, S. cerevisiae is not known for reduced alcohol production without necessary intervention to halt fermentation. The desire to continue using the same yeast species mainly stems from enologists’ understanding of S. cerevisiae fermentation kinetics, while many other yeast species behave differently and are not as well documented [36]. While a viable option, potential modification of the Saccharomyces cerevisiae genome to decrease ethanol production can negatively affect wine quality and multiple modifications are needed to the genome to limit the negative byproducts that become more apparent as alcohol content decreases [37]. Although the usage of S. cerevisiae may still be suitable for low-alcohol wine.

Rather than manipulating the common yeast strains, there is potential value in branching out to other yeast species when developing low or non-alcoholic wines. When developing low-alcohol kiwi wine, using a mixture of Saccharomyces and Wickerhamomyces anomalus yeasts fermented to completion while also producing the positive flavor/odor profiles of the Wickerhamomyces yeast [38]. In a sensory panel survey of using a non-Saccharomyces yeast in production of non-alcoholic beer, while certain metabolites were quantitatively lower than the sensory threshold values, the trained sensory panelists were able to elicit the positive flavor profiles [39]. Similar to craft beer production, the development of low-alcohol wine can decrease the negative consequences of alcohol consumptions and allow the botanical components and polyphenols’ flavor qualities to be better discerned by the consumer [40]. Although a deviation from the norm of winemaking, testing and development of more unconventional yeast strains for wine fermentation may have beneficial effects on the flavor profile when producing low-alcohol wines.

Another potential enological contribution to low-alcohol production is the purposeful arrest of yeast fermentation via insufficient nutrition. While multiple nutrition factors affect yeast digestion, the most significant measure used by enologists is the concentration of yeast assimilable nitrogen (YAN). Sources of YAN are mostly from ammonium and amino acids, and these are necessary to maintain fermentation kinetics to prevent “stuck” or incomplete fermentation [41]. While there is a portion of the necessary YAN present in the grape must, often supplemental nitrogen sources must be added to avoid starvation of the yeast [42]. While it is seen as an issue for traditional winemaking if fermentation becomes stuck due to lack of nutrition, for low-alcohol wine production, the yeast stopping alcohol production prematurely can help to reduce the human intervention or resources needed to reduce alcohol content [43]. Having a lower target YAN amount or simply refraining from adding supplemental nitrogen can naturally stagnate the yeast, although this method can be less predictable in terms of final alcohol or residual sugar content [44]. There may be lower alcohol content in the wine, but the balance of the flavor profile may also detract from the wine quality if too much residual sugar is present.

While insufficient nutrition may not be the goal for producing a well-balanced product, low-alcohol wine from arrested fermentation may also come from temperature shock or sterilization. If stopping fermentation with sufficient nutrition and fermentable sugars, temperature can be used as a control mechanism for manipulating fermentation kinetics. In a study of fermentation at varying temperatures, lower temperatures of 15–25°C saw greater efficiency at producing more ethanol per available sugar content and thus produced wines with greater total alcohol content [45]. Although delayed in the yeast population growth initially, the lower temperature fermentations maintained greater total yeast concentration for longer and consumed the fermentable sugars much more rapidly compared to the 30 and 35°C fermentations [45]. Understanding the yeast population dynamics and tracking fermentation progression are valuable in determining the ideal conditions to stop fermentation. Once the residual sugars and alcohol content are at desired concentrations, rapid temperature changes can preserve these conditions. Cold shocking the yeast by bringing the wine below 10°C or pasteurizing with temperatures around 70°C will stop fermentation and kill the yeast [46]. Both methods require resources to manipulate the surrounding temperatures, which may not be viable for industrial production and rather chemical arrest of fermentation is a better technique. Although better suited for near-complete fermentations, the addition of sulfites and subsequent potassium sorbate will inhibit yeast growth and stabilize the wine [46]. Both the temperature and chemical manipulation of yeast populations to induce incomplete fermentation are viable methods to producing wine with lower alcohol content.

It has also been shown that extraction of the ethanol during fermentation may have beneficial effects on the fermentation kinetics. In a study comparing de novo aromatic compound synthesis and sensory effects of 2% ethanol removal by distillation under vacuum or carbon dioxide (CO₂) stripping, the results showed an increase from both methods in glycerol and isobutanol production with no sensory differences between the vacuum distillation extraction and wine produced without dealcoholization [47]. Although the vacuum distillation and CO₂ stripping processes required conditions that could increase yeast mortality (heat or high gas flow, respectively), the removal of the alcohol allowed for a greater production of aromatic compounds and indicate an increase in those pathways from the removal of medium-chain fatty acids [48]. The removal of ethanol during fermentation demands more resources and interventions but may create a much better flavor profile in the final wine product.

4.2.2 Post-fermentation

To produce low-alcohol wine, a prominent concern of winemaking is compromising between alcohol reduction while retaining the wine’s sensory and flavor profile. Studies have shown flavor profile and aroma thresholds of alcoholic drinks differ when the alcohol is removed, thus a concern is prematurely arresting or reducing fermentation may produce undesirable flavors and it may be better to allow the fermentation to reach completion [39, 40]. If allowed to ferment completely or if fermentation produced greater alcohol than anticipated, additional manipulations can be made to remove excess alcohol accumulation.

As previously described, one viticulture strategy to reduce final alcohol content of the wine is early harvest. This limits the amount of sugar accumulated in the must and may have the added effect of retaining acidity, potentially contributing positively to the overall flavor profile. With decreased available sugar, fermenting an early harvest batch to completion would produce a wine with a lower alcohol content. The produced wine may not be received as well by the consumer for its reduced phenolics and increased acidity [39, 40]. A method winemakers can use to balance the wine is combining the early harvest wine batch with another from later in the season. The mixture of different batches can lower the final alcohol content and increase the overall wine quality. In areas experiencing greater warming and sugar accumulation or for smaller wineries, it can be a good strategy coordinated by the viticulture and enology sides to purposefully harvest an early batch to later blend with a batch harvested at the typical harvest period.

After fermentation, removing extra sugar and/or alcohol of the wine can help to produce a low-alcohol wine with better body, mouthfeel, and overall structure. Certain flavor and aroma compounds can only be produced during the fermentation process, so fermenting for longer may produce wine with a richer flavor profile. If fermentation is arrested, conducted with low-alcohol tolerant yeast, or not given sufficient nutrition, the residual sugar content could detract from the wine’s flavor profile. Removal of the sugars or alcohol could be done via reverse osmosis, membrane filtration, or vacuum distillation [49]. The International Organization of Vine and Wine classifies the process of wine dealcoholizing into three separation techniques: partial vacuum distillation, membrane techniques, and distillation [50]. Partial vacuum evaporation decreases the air pressure in the container to less than the vapor pressure of ethanol and ethanol will then go into the gaseous state to be sucked out. OIV restricts these methods to only be used in wine absent of any organoleptic defects [50]. While some of these methods were previously unaffordable for many smaller-scale winery operations, recent warming patterns leading to increased sugar accumulation have persuaded many winemakers to invest in the necessary equipment. This equipment can easily be used both for the reduction of alcohol in their traditional wine and for the creation of a new platform of low-alcohol wine selections (Table 2).

Methods	Varieties	Impact
Use of Non-Saccharomyces Yeasts [51, 52, 53]	Chardonnay; (Metschnikowia pulcherrima AWRI1149 followed by S. cerevisiae)	Produced wines with a 0.9% (vol/vol) alcohol content; Increased esters and higher alcohols; Reduced volatile acids;
	Shiraz; (Metschnikowia pulcherrima AWRI1149 followed by S. cerevisiae)	Produced wines with a 1.6% (vol/vol) alcohol content; Increased higher alcohols; Reduced volatile acids;
	Trebbiano/Verdicchio; (H. uvarum; Z sapae, Z; bailii, and Z. bisporus)	Displayed a fermentation efficiency that was 62.5% (30.6% lower), while the Zygosaccharomyces species were all similar to Saccharomyces. Increased residue sugar; Increased ethyl acetate;
	Merlot; (co-inoculated M. pulcherrima and S. cerevisiae)	Decreased alcohol by 1%; Increased ethyl acetate, total esters, total higher alcohols, and total sulfur compounds; Received relatively high scores for red fruit and fruit flavor;
	Merlot; (S. uvarum)	Decreased alcohol by 1.7%; Increased total higher alcohols; Received relatively high scores for negative barnyard and meat flavor;
Modified Saccharomyces yeasts [54]	Tempranillo; (glycolytically inefficient yeast, strain TP2A16)	Decreased alcohol by 1%; Increased glycerine; Maintained volatile acid within the acceptable range;
Nanofiltration; (NF) [55]	Verdejo and Garnacha	Dealcoholized alcohol by 2 degrees; Observed no significant differences between the control and the filtered wines; Identified the two-stage process without backflush as the most effective NF technique;
Pervaporation (PV) + nanofiltration (NF) [56]	Verdejo	Dealcoholized alcohol by 1.7 degrees; Exhibited an aroma content similar to that of the original must; Demonstrated a taste similar to control wines; The combination of PV and the two-stage NF yielded the best results;
Spinning cone column distillation [57]	13 red, 2 rose, and 4 white wines	Reduced antioxidant activity due to loss of sulfur dioxide; Showed elevated levels of phenolic compounds as a result of concentration;
Osmotic distillation (OD) [58]	Falanghina	Dealcoholized at various alcohol content levels ranging from 9.8% to 0.3% ABV; Preserved levels of total phenols, flavonoids, organic acids and total acidity; Decreased volatile compounds with the progressive removal of alcohol;
Osmotic distillation (OD)-reverse osmosis (RO) [59]	Montepulciano d’Abruzzo	Dealcoholized alcohol content from 8% to 5% ABV; Showed a better retention of the main chemical properties and volatile compounds;
Membrane contactor (MC); Distillation under Vacuum; (D) [60]	Rosé wine, Pelaverga; Barbera	Dealcoholized alcohol at 5% ABV; Retained organic acids, cations, polyphenols, and anthocyanins; Showed a reduction in volatile compounds;
Reverse; osmosis-evaporative Perstraction; (RO-EP) [61, 62]	Three wines sourced from industry	Dealcoholized alcohol content from 5% to 0.5% ABV; Enhanced color intensity, phenolics and organic acids; Reduced certain fermentation volatiles, particularly ethyl esters;
	Cabernet Sauvignon	Lower the alcohol content by between 1.8% and 2.5% ABV; Exhibited reduced acidity, sweetness, bitterness, saltiness, and/or body; Enhanced astringency;

Table 2.

Winemaking practices for low-alcohol wine production.

5. The economics of production

The economic value to the consumers and producers is nuanced, with attractants and deterrents from the production and consumption of low-alcohol wine. The public perception, influenced by health organizations and general trends in alcohol consumption, has shown that there may be demand for wine products lower in alcohol and winemakers could capitalize on this opportunity. Conversely, the pricing of these more resource intensive products may not fit the producer and consumers’ wishes and the profitability may be lower than traditional wine.

While consumers can gain health benefits from low-alcohol wine, wine producers can also reap the economic benefits. As the health risks of alcohol consumption strain public health infrastructure, many countries and organizations have proposed an increase in the excise tax rates of alcoholic beverages. In 2021, the World Health Organization (WHO) began considering the implications of doubling the excise tax on alcohol in an effort to limit the prevalence of alcohol-attributed cancers [15]. This hypothetical situation showed a decrease in other alcohol commodities but not wine due to many European Union (EU) WHO member states having no excise tax rate on wine. After the WHO study was published, a criticism emerged that alcohol consumption via wine is largely prevalent in these European countries with no excise tax and wine can make up one-third of the per capita alcohol consumption in these populations [6]. If there was an initiative to increase the excise tax rate on alcohol to decrease preventable, alcohol-attributable diseases, it stands to reason the countries with no or minimal wine excise tax would likely have to enact a wine excise tax. In Australia, a survey was conducted to gain an understanding of the drinking population and whether there is a market potential for low-alcohol wine if the excise tax rate increased [8]. The results of the survey found that there is market potential in consumers of wine and light beer but consumers of full-strength beer, spirits, and cocktails are less likely to purchase low-alcohol products. With current wine consumers more open to low-alcohol alternatives, the market potential for low-alcohol wine, and avoidance of increased excise tax on wine, producers should consider increasing their investment in the development of viable low-alcohol wine alternatives.

Although there may be market potential in capturing the niche of consumers who would prefer a low-alcohol alternative, many consumers would probably not change to drinking lower-alcohol wine without an economic incentive. With not enough market research in the existing low-alcohol wine options, these surveys regard other healthy food alternatives that are widely known. In a survey conducted on fast-food consumers and their perceptions on healthy food options, there was a clear trend that most people surveyed would prefer healthier menus and more sustainable items but only 7% of the participants’ meals included healthier food choices already available [63]. The researchers contributed this lack of throughput with people’s affinity for taste, price, and habit, which is also likely with consumers who claim to want more low-alcohol options.

Public perception of products which have had something removed may also influence consumer purchasing and drinking trends for low-alcohol wines. In another beverage product, milk, a survey found that average shoppers believed lower fat milk to be more expensive and whole milk to be a better source of calcium, which could be deterrents in their purchase of low-fat milk [64]. There does seem to be changes in the public’s perception of these available alternatives as health trends highlight the positive effects of changing consumption habits. An example of this trend is the recent increase in coffee consumers choosing decaffeinated over traditional. Although the perception of decaffeinated coffee is similar to low-fat milk in its greater expense, the negative effects of traditional coffee’s high caffeine amount deter consumers and they shift toward the healthier option with the premium price [65].

While there does seem to be a lack of representation of low-alcohol wine and the recommendations of health organizations would do well to encourage the production, customers would perhaps not pay for a premium wine price with lesser alcohol. The marketing of low-alcohol wine must also not oversell the health benefits and dupe the consumers that the products should be consumed with less regard for the alcohol content.

6. Challenges

While low-alcohol wine production may be a new niche that the industry can explore, there are considerable challenges that must be acknowledged. For both winemakers and winegrowers, the different methods that must be enacted to maximize wine quality while minimizing alcohol will likely differ from common practices. There are concerns over the viticulture practices in light of climate change and how to manage accordingly, and most of the expected challenges are with the winemaking side. Fermentation kinetics, microbial spoilage, instability, and aging all have problems that can arise from lower alcohol conditions.

As a support from the winegrowing side, it is best practice to plan whether a harvest will be used for low-alcohol wine prior to the grape growing season to better prepare the must for production. With a lower alcohol target, the desired sugar content of the grape must may be lower and thus the strategies explained above would be very beneficial to implement. As well, the post-fermentation practice of batch blending to reduce the final alcohol content can only be done if there was an early harvest batch to mix [66]. This early harvest would have higher acidity and lower sugar than growers would be expecting, so communication from the winemaking to the winegrowing teams is critical.

While producing the final product, the wine must be monitored to determine whether there are unwanted fermentation kinetics or microbial populations spoiling the wine. When deciding on the usage of non-Saccharomyces cerevisiae yeasts, most other wine yeasts are not as vigorous or competitive potentially becoming outcompeted by wild yeast [67]. Although there is a chance that the native yeast and microbes may create new, interesting flavors, there is a much larger probability that these wild yeasts will produce off-flavors, lower quality, or unusable wine. As mentioned before, the fermentation kinetics of Saccharomyces is well-known and well understood, while other wine yeasts less so. Wine yeasts that produce less alcohol or are less alcohol tolerant may arrest fermentation too early and leave more residual sugars than desired. An issue with too much sugar or not enough alcohol is the increased likelihood of microbial spoilage and instability. Alcohol is a natural sanitizer and can normally keep the wine microbe spoilage controlled, but may not in a situation of low alcohol with high sugars for the microbes to feed on [68]. In this case, Saccharomyces cerevisiae may still be used sequentially to digest the sugars further or other technologies to inactivate the microbes while also trying to retain the low-alcohol content. After fermentation, there is still a higher risk of microbial spoilage in the production and aging process. Meticulous attention to hygiene and sanitization is necessary to prepare the wine for aging, especially for long-term aging [69].

For the winemaking industry, the production of low-alcohol wine presents a new opportunity for market growth but it is not without limitations. For grape growing practices, low-alcohol wine has some methods that can better prepare the harvest for the fermentation process. While the downsides and the need for decreasing alcohol consumption are a social issue, a wine industry issue is that alcohol prevents many issues during fermentation that must then be carefully monitored to create a high-quality product. Low-alcohol wine production should be undertaken after determining the risks and having a strategy to maximize the quality and economic gain while minimizing any product loss.

7. Future work

While there is much research done into possible avenues for producing low-alcohol wine from traditional wine methods, there is still much to be explored to discover better practices and create efficiencies. While the viticulture practices are well known to lower sugar accumulation, mostly discovered from general practices needed to grow in warmer climates, there is insufficient research into enological practices in low-alcohol wine production.

As explained previously, many enological practices for traditional wine do not correlate well with low-alcohol production and studies into yeasts, fermentation kinetics, and industry-scale production are needed. Saccharomyces cerevisiae has been extensively researched and its fermentation kinetics in all wine varieties has been documented, which makes it a staple for any enologist. When branching into alternative yeast species, there is much less known about their respective fermentation kinetics. More depth of knowledge for these yeasts would not only help with low-alcohol wine production, but also with expanding the repertoire of winemakers to create new flavor profiles [70]. While it may be more comfortable for winemakers to continue using Saccharomyces cerevisiae for fermentation and then undergoing either batch mixing or ethanol extraction, this method is both resource/time intensive as well as unknown whether the flavor profile would be adequately balanced [39, 67]. Traditional winemaking has determined certain aroma or odor thresholds for both positive and negative flavor compounds, yet the removal of alcohol can lower this threshold. This can either be beneficial by highlighting more desired flavors, or detrimental with increasing the spoilage flavors or changing the flavor profile too far from consumers’ expectations of certain varieties or wine styles.

In combination with the enological research necessary for better low-alcohol wine production, there also is a need for more studies using large-scale production. Many of the studies conducted and published on reducing alcohol content are scaled to researchers’ capabilities and this may not translate to large, industrial production. Two areas of note are the ethanol extraction methods and hygienic aging, which may have more complications for larger wineries. The resources needed (electricity, labor, equipment, etc.) for certain methods may not be economically viable to scale up to larger production which may limit the integration of these techniques and may limit the production of low-alcohol wine to smaller facilities.

There is still much to learn about winemaking transitioning from producing traditional wine to low-alcohol wine. Reduction of alcohol is a necessary skill due to climatic changes, with the added benefit of consumer preferences and health initiatives, and the industry would do well to invest in the research needed to create desired flavor profiles and efficiencies in the process.

8. Conclusion

Millenia in the making, traditional wine production is filled with cultural and religious significance, but modern trends have moved toward low-alcohol alternatives. Both government and non-government officials have researched the health detriment of alcohol consumption and favor the implementation of economic disincentives to traditional wine to encourage the public to consume less alcohol. With this greater public image of alcohol overconsumption, consumer preferences have steadily trended toward alternative beverages like light beers and low-alcohol wines. Wines with reduced alcohol content also benefit from showcasing the positive health aspects of wine production. Consumer surveys have shown the sale of low-alcohol wine as a functional food may be well received and compensated by the market, which is encouraging to hear for winemakers.

As climate issues and terroir changes favor greater sugar accumulation, vineyard and winemaking practices should be implemented to counter the increased alcohol concentration. Rootstock selection, vigor manipulation, reducing photosynthesis, and timing harvest all help to decrease the fermentable sugars in the must. These practices can also facilitate the development of other flavor compounds, setting up the must for a better flavor profile after harvest. Winemaking practices of yeast selection, premature fermentation arrest, batch blending, and alcohol removal can be implemented to produce a low-alcohol product with better mouthfeel, body, structure, and an overall richer flavor profile.

While there seems for be a promising market for the product, the production of low-alcohol wine has numerous challenges. Grape growers and winemakers will need to adopt certain methods to best prepare and ferment the must to retain a high-quality wine while reducing the alcohol content. Challenges that must be faced by each team include climate change on terroir for the viticulture side and fermentation kinetics, microbial spoilage, and instability for winemakers. Production on a larger scale must also be deliberately planned and monitored to prevent the spoilage with less alcohol to sanitize. Despite its potential, low-alcohol wine requires a thorough strategy to balance the economic gains while maintaining quality and minimizing product loss. More research is needed in the industry to understand new efficiencies or eliminate certain issues of the production of low-alcohol wine.