White Winemaking Research Articles

Effects of winemaking techniques on the volatile compounds of Chelva wines

This study aimed to investigate the impact of three winemaking techniques on the volatile compounds and sensory profile of La Mancha Chelva wines, including wine elaborated by traditional white winemaking process (CW), wine enzymatically treated (WE), wine from must with skin contact treatment (SCW) and wine aging on lees (WL). A total of 32 varietal aroma compounds and 44 volatile compounds formed principally during alcoholic fermentation were identified and quantified by GC-MS independently of the winemaking technique and vintage year. WE showed the highest contents of terpenes, C13-norisoprenoids and benzenic compounds, SCW displayed major concentrations of C6 compounds whereas WL exhibited the major concentrations of the principal groups of volatile compounds formed mainly during alcoholic fermentation. All wines showed the same sequence of aromatic series, with the highest aroma contribution being those of the fruity, sweet and fatty series. The differences found in volatile compounds modified the sensory aroma profile of CW enhanced the main attributes. These results reveal that the winemaking process used had an important effect on the volatile composition of Chelva wines and can be used for optimizing the elaboration method to ensure wines in concordance with consumer preferences and that preserved the distinctive aromatic typicity of Cheva wines.

Complexity of the effects of pre-fermentation oxygenation, skin contact and use of pectolytic enzymes in white winemaking as revealed by comprehensive proteomics and volatilomics analysis

Ion exchange chromatography and SDS-PAGE followed by identification by MALDI-TOF/TOF, and two-dimensional gas chromatography with time-of-flight mass spectrometry (GC × GC-TOF-MS) were used for comprehensive proteomics and volatilomics evaluation of the effects of pre-fermentative oxygenation, skin contact and use of pectolytic enzymes in production of Malvazija istarska white wine, respectively. Many protein species and an unprecedented number of volatiles have been identified and (semi)quantified, revealing high complexity of the observed effects. Compared to a standard control wine, oxygenation treatment modulated the protein composition and resulted with a volatilome characterized by decreased levels of several important volatiles. Skin contact treatments, especially in combination with pectolytic enzymes, significantly increased the levels of a large number of proteins, but were also deprived of particular protein species found in other wines. Wines obtained by skin contact with exogenous enzymes exhibited the most complex volatile composition with increased levels of many key monoterpenoids, alcohols and esters.

Sur lies élevage practice to modulate the features of red wines from calcareous soils with different textures.

In Sicilian calcareous soils, red wines often display unripeness and bitterness features. To enhance wine quality, we employed the 'sur lies élevage' technique, involving prolonged contact of dead yeast cells with the wine to favor the extraction of yeast cellular components through cell lysis. The 7 month treatment utilized two types of Chardonnay lies: fresh and previously matured. To overcome challenges in retrieving lies from red winemaking, we have recovered the lies from a white winemaking. Additionally, the lies underwent a preliminary passage on a red wine to minimize color adsorption on yeast cell walls. The sur lies treatment effectively reduced astringency, bitterness, and brown pigment in wines, with partial removal of red color. It successfully eliminated quercetin aglycone and induced remarkable changes in the aromatic profile, showing increased ethyl esters and relative fatty acids. Sensory evaluations revealed sur lies-treated wines had fruitier and more complex characteristics compared to untreated wines. Matured lies had a greater impact on enhancing fruitiness than fresh lies. The treatments mitigated the unripeness and bitterness of studied wines. Sur lies treatment improved the aromatic profile, leading to fruitier and more complex notes, enhancing overall sensory quality. Matured lies showed greater efficacy in elevating fruitiness than fresh lies. These findings highlight the value of the sur lies technique in enhancing the quality and sensory attributes of Nero d'Avola and Syrah wines from Sicilian calcareous soils. © 2023 Society of Chemical Industry.

Dosing oxygen from the early stages of white winemaking: Effect on oxidation–reduction potential, browning stability, volatile composition, and sensory properties

This study investigated the effect of controlled oxygen addition during alcoholic fermentation (4 mg/L, at 2nd, 4th, 6th, 10th, 14th, 16th, 20th day) and aging on lees (2 mg/L, every 15 days for 3 months) in a stainless-steel tank for white wine production from a nearly neutral grape. Under less reductive conditions (Ox), alcoholic fermentation was completed in 27 days, whereas one extra week was required under more reductive conditions (no-Ox). The greatest amount of dissolved oxygen in Ox wine triggered the increase of redox potential (EH) starting from the end of alcoholic fermentation and throughout aging (169 and 150 mV in Ox and no-Ox wine, respectively), also improving the wine resistance to browning. Oxygen addition from the early stages of winemaking significantly modulated volatile composition and sensory attributes, which may contribute to the diversification of wine style.

STUDIES ON THE INFLUENCE OF THE PELICULAR MACERATION PROCESS ON THE QUALITY AND TYPICALITY OF SEMI-AROMATIC AND AROMATIC WINES

Traditionally, when making white wines, the musts are subjected to clarification and settling, even those from harvests in perfect phytosanitary condition. The increasingly perfected technical and technological procedures, involved in the operation of clarifying and deburring the musts, lead to the total removal of undesirable impurities, but also of the small fragments of skins and core, the only carriers of varietal aromas specific to each variety. In such situations, wines lacking fruitiness, aromatic "expressiveness" and varietal typicality result. In order to avoid such inconveniences, recently investigations have been intensified on the topic of improving white winemaking technologies, showing that the pellicular maceration is particularly appropriate, especially when the grapes are, at the time of harvesting, in a perfect state phytosanitary and are well matured. By applying pellicular maceration, notable results are obtained in the vinification of semi-aromatic (Sauvignon) and aromatic (Muscat Ottonel) grapes, but significant improvements were also obtained when using grapes of "neutral" aromatic varieties, such as those belonging to the Chardonnay variety.

Biotechnological strategies to reduce the doses of sulfur dioxide in white winemaking and avoid problems of browning

This communication studies some possible strategies to reduce or even to replace sulfur dioxide in winemaking. Specifically, the aim of this work was to study the protective effect against oxidation of a commercial inactivated dry yeast (IDY) with very high level of glutathione, and of a selected non-Saccharomyces yeast, Metschnikowia pulcherrima strain in comparison with sulfur dioxide.

Impact of fermentation-temperature management combined with specific yeast choice on energy savings in white winemaking

Heat removal significantly impacts energy request in the winery and is related to the temperature control of wine tanks during the fermentation process and the wine maturation phase. The aim of this work was twin: first, to determine the heat dissipated from tanks under different temperature fermentation programs, to evaluate the impact of temperature management combined with specific yeast choice on energy saving during industrial-scale (450 hL) white vinification. Second, to explore the applicability of such protocols, and the extent of the potential effects thereof, through a survey. Comparative winemaking tests were carried out by using properly chosen yeasts during fermentation of Glera and Pinot Grigio musts at usual winery temperature (15 or 17-15 °C) and 19 °C, verifying the quality of the resulting wines in term of sensory, chemical and aromatic features. Fermentation required on average 7.0 Wh dm-3 at 19 °C and 10.3 Wh dm-3 must at 15/17-15 °C, reducing energy use by ~32% at the higher temperature, without compromising sensory, chemical, and aromatic profiles of wines. Then, the potential widespread of those effects was investigated through a survey involving several (n>100) wineries: among others, questions about vinification volumes, usual fermentation temperatures and attitude towards energy-saving innovations were asked to winemakers. Our results suggest that wineries can adopt a more sustainable winemaking process with low energy consumption and that this choice may have a relevant impact on white-winemaking energy consumption in the Italian context. Indeed, ~70% of a sample of winemakers representing an overall production of 1.300.000 hL, declared a willingness to increase their usual fermentation temperature if research data support energy-saving expectations without compromising wine quality.

Bioprotection on Chardonnay Grape: Limits and Impacts of Settling Parameters

Background and Aims. If bioprotection has already been proven to limit the development of spoilage flora on musts, its effectiveness against oxidation depends on the winemaking process. To optimize its application, this study analyzed the evolution of the chemical composition of the bioprotected musts and wines, according to different settling routes. Their impacts on the organoleptic characteristics of wines were also studied. Methods and Results. A bioprotected must was subjected to 6 different maceration routes before AF (triplicates), varying the duration and temperature parameters. A temperature value ≤12°C was the main factor independently of the duration which allowed a good implantation of the bioprotectant. An increase of the maceration duration at 12°C led to browning of the must, without significant effect on the final color of the wine, which was felt as more “floral,” with more length in the mouth. Conclusions. The bioprotectant implantation and its effectiveness on the sensory profile of the wine was guaranteed at maceration temperature values lower than 12°C. Significance of the Study. This study participates in the improvement of the bioprotection management in white winemaking, with the guarantee of a positive impact of the prefermentation maceration without sulphites on the organoleptic profile of the wines.

Antioxidant activity of yeast derivatives: Evaluation of their application to enhance the oxidative stability of white wine

Maintaining wine oxidative stability and reducing SO2 addition remains a challenge in white winemaking. This study aimed to evaluate the antioxidant capacity of two yeast derivatives (YDs) with a specific composition: one was rich in reducing compounds, including glutathione (YDR), and the other was rich in lipid compounds (YDL). Both YDs were evaluated for their antiradical activity in model wine solution (by the DPPH method) and for their capacity to consume oxygen in model wine solution and in white wine. Antiradical activity in both matrixes and oxygen consumption rate in wine were higher for YDL than for YDR. However, the addition of YDR to wine limited the production of acetaldehyde and preserved glutathione content to a greater extent after wine oxygenation. The sensory analysis confirmed that both YDs, in particular YDL, limited the occurrence of oxidation off-odours when no SO2 was added. These data suggest that the use of YDs could be effectively implemented in low-sulfite winemaking in order to improve the antioxidant protection of white wine.

Red and white wine lees as a novel source of emulsifiers and foaming agents

Wine lees are an under-exploited sludge-like material mainly consisting of yeast cells that, upon fermentation, settle at the bottom of wine tanks. Lees from commercial red and white winemaking were processed to yield mannoprotein-rich extracts. An established autoclave-based extraction protocol, as well as a simplified version of it, were applied. The composition of the obtained wine lees extracts was determined. Extracts were tested as emulsifying and foaming agents in model food systems and benchmarked against analogues extracts derived from laboratory-grown yeast cultures of the same two strains used for red and white wines production. All extracts showed good functionalities as emulsifying and foaming agents. However, some differences were noted in both composition and functionality, and these were related to the purification process used, yeast strain, and to the extract's origin (red lees, white lees, lab-grown yeasts). Extracts from real wine lees, which contained also grape-derived polyphenols, performed equally or better than the corresponding extracts derived from laboratory-grown yeast cultures of the same strains. Both red and white wine lees can be a novel and effective source of emulsifiers and foaming agents representing a valid alternative to the yeast biomass produced in bioreactors to be potentially used in the food industry.

A Knowledge-Based System as a Sustainable Software Application for the Supervision and Intelligent Control of an Alcoholic Fermentation Process

One goal of specialists in food processing is to increase production efficiency in accordance with sustainability by optimising the consumption of raw food materials, water, and energy. One way to achieve this purpose is to develop new methods for process monitoring and control. In the winemaking industry, there is a lack of procedures regarding the common work based on knowledge acquisition and intelligent control. In the present article, we developed and tested a knowledge-based system for the alcoholic fermentation process of white winemaking while considering the main phases: the latent phase, exponential growth phase, and decay phase. The automatic control of the white wine’s alcoholic fermentation process was designed as a system on three levels. Level zero represents the measurement and adjustment loops of the bioreactor. At the first level of control, the three phases of the process are detected functions of the characteristics of the fermentation medium (the initial substrate concentration, the nitrogen assimilable content, and the initial concentration of biomass) and, thus, functions on the phase’s duration. The second level achieves the sequence supervision of the process (the operation sequence of a fermentation batch) and transforms the process into a continuous one. This control level ensures the quality of the process as well as its diagnosis. This software application can be extended to the industrial scale and can be improved by using further artificial intelligence techniques.

Conservation of 87Sr/86Sr During Wine-Making of White Wines: A Geochemical Fingerprint of Geographical Provenance and Quality Production

The measuring of 87Sr/86Sr in wine, grape and bioavailable soil fraction samples with the same uncertainty of geological materials allows to fully compare the whole wine-production chain with the peculiar geochemical isotope signature of any geographic area. Indeed, this signature is the same that the final product inherited by the soil bioavailable fraction and, in turn, by the geological substratum of the vineyard. On the other hand, the few data available in literature referred to white wines cast doubts for the use of this geographic tracer due to the common use of geological-derived additives, such as bentonite, in the white wine-making procedure, which may overprint the original geochemical signature of the vineyard substratum. To tackle this issue, we analysed the Sr-isotope compositions of four white wines produced over a period of almost 10 years in a high-quality organic farm, located on the volcanic units of the Vulsini Volcanic District (southern Tuscany, Italy). The 87Sr/86Sr values of rock, soil, grape, grape juice, must, and wine were compared among them and furtherly weight against the isotope fingerprint of the bentonite and yeast employed during the wine-making process. The 87Sr/86Sr values from the entire white-wine production chain reveal that no variations are observed from the signature imprinted by the original geological substratum (rocks and soils), suggesting that no further contribution is given by the addition of bentonite and yeast to the white wine Sr-isotope values. On the other hand, intermediate 87Sr/86Sr compositions are found when grapes from different vineyards are used for making multi-cultivar wine blends. Indeed, the experimental data clearly show that the Sr isotope composition is maintained through the wine-making process for white as well as for red wines. Both grape and final wine preserved the isotope signature inherited from the labile fraction of the soil where the vines are farmed. Our data thus confirm, also for white wines, the robustness of Sr-isotope tool in studies where it is important to define terroirs and geographic provenance.

Effect of vine-shoot and oak extract foliar grapevine applications on oenological parameters, phenolic acids and glutathione content of white musts and wines

Aim: An oxidation process frequently occurs during white winemaking, affecting its quality. The aim was to study, for two years (2013 and 2014), the effects that foliar applications of vine-shoot (Airén (AVS) and Moscatel (MVS)) and oak wood (OW) extracts on Airén grapevines have on wine color, and must and wine glutathione, trans-GRP, trans-caftaric acid, and trans-p-coutaric acid content.Methods and results: These compounds were analyzed by HPLC. The results showed that, in general, foliar application of Airén vine-shoot extracts did not affect glutathione concentration, and the other treatments decreased it. AVS2013-50 and AVS2014 samples were characterized by a high content of glutathione and trans-GRP, while MVS2014 samples retain high levels of trans-caftaric acid. trans-p-Coutaric acid concentration decreased after AVS2013 treatment, meanwhile in the 2014 season all applications increased its content. The content of these compounds in the wines was similar to those obtained in the musts. OW2013 showed the lowest value of Abs 420, likely because this treatment decreased glutathione concentration in musts.Conclusions: The foliar applications of vine-shoots and oak extracts on Airén grapevines had a clear effect in reducing the wine alcohol degree and Baumé in case of grapes. This finding is interesting in the context of the current global warming change scenario. Although the two vintages studied were different, an improvement in the color quality was observed in both. The content of glutathione decreased from must to wine: the content in both matrices was lower in treated samples than in control samples, except for Airén extracts in both vintages. This means that glutathione is oxidized, avoiding the oxidation of other must and wine molecules.Significance and impact of the study: These findings are important in relation to revalorizing waste from the vineyard, and thus being able to improve the quality of the white wine in relation to the oxidation processes that take place in the winemaking process.

From grape to wine: Fate of ochratoxin A during red, rose, and white winemaking process and the presence of ochratoxin derivatives in the final products

The presence of ochratoxin A (OTA) in wine is mainly due to the contamination of grapes by Aspergillus carbonarius and A. niger, still in the vineyard or at stages prior to winemaking. Throughout winemaking process, although there is a reduction in OTA levels, modified mycotoxins may also be formed. In fact, modified mycotoxins are compounds that normally remain undetectable during the conventional analysis used for the parent toxin. In this context, the current study aimed to evaluate the effect of grape variety and winemaking steps on OTA fate as well as the formation of modified ochratoxins. White, rose and red wines were prepared from Muscat Italia, Syrah and Touriga Nacional varieties, respectively. OTA was determined during different steps of winemaking by UHPLC-ESI-MS/MS. Identification of ochratoxin derivatives was performed using tandem MS experiments. A reduction of 90.72, 92.44 and 88.15% in OTA levels was observed for white, rose and red wines, respectively. Among the sought targets, the following ochratoxin-derived candidates were identified: ochratoxin β, ochratoxin α methyl ester, ochratoxin B methyl ester, ochratoxin A methyl ester, ethylamide ochratoxin A, ochratoxin C and ochratoxin A glucose ester. These results indicate that the formation of ochratoxin derivatives leads to an underestimation of total mycotoxin levels in wine and, therefore, the inclusion of techniques for multi-mycotoxins detection should be considered.

Cross-flow filtration of lees grape juice for non-aromatic white wine production: a case study on an Italian PDO

During white winemaking, after clarification, a considerable amount of juice remains trapped in the lees. Recently, cross-flow filtration has become popular to recover a large amount of juice from lees. However, high juice recovery is observed to be consistent with a decrease in wine quality, while low recovery reduces the amount of wine that can be produced. Therefore, this study aims to find the optimal compromise between quantity and quality. We tested at industrial scale and in three replicates, qualitative changes in an elite Italian white wine as a function of different amounts of juice recovered. The length of the filtration cycle affected the juice’s chemical parameters. In some cases, uncontrolled alcoholic fermentation started before the yeast inoculum, leading to a small increase in ethanol, and higher acetic acid and ethyl acetate concentrations that can be find in the resulting wines. The phenomenon was particularly apparent in longer fermentation cycles. Furthermore, longer filtration cycles increased juice acidity and potassium, while the resulting wines changed in terms of pH, glycerol, and volatile profile. Several grape-related compounds were found in wines at different concentrations as a function of the amount of juice recovered. In particular, Z3-hexen-1-ol, p-cymene, β-ionone, and benzyl alcohol were found to increase, reaching a maximum at 65% of recovered juice before decreasing. Furthermore, several fermentation-related compounds were found to change according to the length of the filtration cycle. Our work identifies an optimal recovery point of 65%. This percentage appears the best trade-off between the flavor of wines, fermentation risk management, and the amount of juice recovered.

Polyphenolic Characterization of Grape Skins and Seeds of Four Italian Red Cultivars at Harvest and after Fermentative Maceration.

Agro-industry byproducts can still contain large amounts of phenolic compounds, and one of the richest sources are grape skins and seeds as grape pomace, both fermented (red winemaking) and unfermented (white winemaking). The residual polyphenolic content depends on various factors such as grape variety, vintage, and winemaking technique. In this work, four red grape varieties cultivated in northern Italy were studied: Albarossa, Barbera, Nebbiolo, and Uvalino. The work was aimed at studying the polyphenolic composition of skins and seeds from fresh grapes and from the corresponding pomace after fermentative maceration, to assess the actual importance of the varietal differences when processing winemaking byproducts for the extraction of phenolic compounds. The skin and seed extracts were prepared by solvent extraction with a 50% hydroalcoholic solution. The polyphenolic composition of all extracts was determined by spectrophotometry and high-performance liquid chromatography (HPLC); the content and the monomer composition of condensed tannins were determined by phloroglucinolysis; the antioxidant capacity was measured with the ABTS (2,2’-azinobis-(3-ethylbenzothiazoline-6- sulfonate)) method. The antioxidant capacity was higher for the seeds than for the skins, and it was positively correlated with the condensed tannins content. Significant differences in polyphenolic composition of fresh grape skins and seeds were observed between the different cultivars. In particular, Barbera and Albarossa skins were significantly distinguished from Nebbiolo and Uvalino skins for a higher content of anthocyanins and a lower content of vanillin-reactive flavans and condensed tannins; regarding seeds, Barbera and Albarossa had a lower content of vanillin-reactive flavans, proanthocyanidins, and condensed tannins than Nebbiolo and Uvalino. The winemaking process extracted the phenolic compounds to a different extent from skins and seeds, regardless of the cultivar. The differences between cultivars in the polyphenolic profile disappeared after fermentative maceration.

Proanthocyanidin content as an astringency estimation tool and maturation index in red and white winemaking technology

Selecting the appropriate type of barrel for wine maturation but also deciding on the optimum maturation length, is a challenge for winemakers. As different types of barrel woods emerge, it is of great importance for a guideline to be established, which could facilitate winemaking decisions. Since the sensory perception of the finished wine, and particularly the intensity of astringency, is a decisive factor for the quality of a barrel-aged wine, in this experiment, the structural characteristics of wine proanthocyanidins were determined and their correlation with astringency was established. According to the results obtained, the proanthocyanidin content and the type of subunit that is dominant in tannin chains could be used to construct an astringency estimation model. The findings could provide winemakers with a useful tool when deciding how long to mature a specific type of wine in a specific wood container without making it appear coarse and astringent.

Tracking polysaccharides during white winemaking using glycan microarrays reveals glycoprotein-rich sediments.

Winemaking results in a significant amount of sediments that are formed in the tanks, the vats and in the bottles before and after fermentation. Little is known about the biochemical composition of these sediments apart from the fact that they are assumed to be derived in large part from the grape matrix. Glycan microarray technology offers a relatively rapid means to track the polysaccharides from their origin in the grape material and throughout the various steps in the winemaking process. In this study Comprehensive Microarray Polymer Profiling (CoMPP) was used to investigate the glycan-rich composition of particularly white grapes during winemaking and then investigate the effects of recombinant and commercial enzyme formulations on wine sediment compositions. The gross lees or sediments produced in the absence of enzymes were found to be composed of an abundance of homogalacturonans, rhamnogalacturonans, arabinans and galactans in addition to an abundance of extensins and arabinogalactan proteins. The addition of enzymes was shown to strip off the homogalacturonan and much of the rhamnogalacturonan with its side chains revealing a sediment layer composed almost exclusively of extensins and arabinogalactan proteins. The effect of winemaking techniques was shown to have an effect on the glycan-rich wine sediment compositions and holds implications for the management of gross lees in a winery environment.

Acid Lactic Bacteria as a Bio-Preservant for Grape Pomace Beverage

A probiotized juice may be an advantage as it provides an alternative to probiotic dairy products. In addition, the use of agricultural residue to supplement a probiotic juice may be a solution for overproduction of this organic material. Many studies have been developed with fruit residues; however a definitive solution to this environmental problem has not yet been established. Therefore the objective of this study was to propose a probiotized juice using lactic bacteria that, besides functioning as starter culture, has a potential biopreservative action and provide suitable stability for the final product. A fermented beverage was formulated using commercial grape juice, Vitis vinifera Pinot noir grape pomace and lactic bacteria. Pathogenic strains were used to simulate a microbial contamination. The procedures were carried out according to the American Public Health Association and the results were expressed in media with standard deviation using statistical analyses performed by Prism. Lactic bacteria showed a cell growth around 4 log CFU/ml. There was a significant decrease in pH values (p < 0.05) when pure grape juice was fermented. The grape juice supplemented with grape pomace from white winemaking was able to induce a higher growth of lactic bacteria population during fermentation, around 1 log cycle CFU/mL, comparing to juice without supplementation. The beverage containing grape juice, water and pomace also presented growth on lactic bacteria population but Lactobacillus rhamnosus reached a higher concentration, of approximately 108 CFU/ml after 12 hour of fermentation. This was also observed when beverages were stored, only L. rhamnosus remained viable for ten days at 10oC. For all beverage samples contaminated with pathogens, the lactic bacteria population remained around 2 log CFU/g above the added pathogen population, and the final probiotic population was above 108 CFU/mL, but L. rhamnosus wasn`t able to reduce significantly pathogenic strains, however a bacteriostatic effect was observed. A probiotic grape juice supplemented with pomace was produced with viable probiotic cell during 12 hours fermentation and stored for 10 days under refrigeration temperature. And a potential bacteriostatic effect against food pathogens was observed.

Metabolism of Schizosaccharomyces pombe under reduced osmotic stress conditions afforded by fed-batch alcoholic fermentation of white grape must

Strains of Schizosaccharomyces pombe are being increasingly investigated with regards to their grape winemaking potential either in combination with the typical production yeast, Saccharomyces cerevisiae, or in monoseptic fermentations. Their ethanol tolerance and ability to degrade L-malic acid is oenologically convenient but contrasts with the comparatively high acetic acid and acetaldehyde formation potential which is considered undesirable, especially in white winemaking. The purpose of this work was to investigate the performance of a selected S. pombe strain in monoseptic femerntations of white grape must. Traditional batch fermentations were compared with an innovative and automated fed-batch fermentation technique were sugar concentrations are kept low during fermentations to decrease sugar induced osmotic stress. Because of its known effect on growth and ethanol tolerance, the effect of Mg was also tested. While Mg supplementation was not shown to significantly influence residual values of sugars, ethanol, glycerol, organic acids and acetaldehyde, the application of the fed-batch technique led to a fundamental change in yeast physiology. While glycerol values were only slightly reduced, the fed-batch approach allowed obtaining wines devoid of acetic acid whose levels were considerable in wines produced by the traditional batch technique (0.6 g/L). The work demonstrates that the acetic acid metabolism of S. pombe is associated to sugar induced osmotic stress such as for S. cerevisiae, too, and may be controlled by application of suitable fermentation techniques for winemaking.