Wine Faults

Lesson #1 – From the Vineyard to the Winery: Defects Caused by the Surrounding Environment

Fabio Mencarelli | University of Pisa

The grapevine is one of the plants most actively involved in exchange with the external environment: through its stomata and lenticels, it absorbs not only water vapor but also volatile organic compounds (VOCs) present in the surrounding air, which can travel all the way to the grape and influence the quality of the resulting wine.
Among the most significant defects are the volatile phenols responsible for “smoke taint”—the smoky aroma produced by fires—and compounds derived from vehicle emissions in vineyards located near major roadways. On the other hand, certain tree species such as eucalyptus, pine, or broom can impart balsamic aromatic compounds to the grapes that enrich the wine’s sensory profile.
This lecture explores the mechanisms of absorption and transport of these compounds within the plant, the influence of leaf morphology on these processes, strategies for preventing or removing unwanted VOCs, and methods for preserving the beneficial ones during winemaking.

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Speaker Bio
Full Professor in the Department of Agricultural, Food, and Agro-Environmental Sciences at the University of Pisa, where he teaches Enology and Food Preservation and Processing. His research has focused on post-harvest technologies for wine grapes, with an emphasis on drying processes, temperature and gas management during fermentation, and the application of non-destructive analytical technologies. He contributes to the leading national trade publications in the sector: *L’Enologo*, *VQ&Q*, and *Il Corriere Vinicolo*.

Lesson #2 – Defects from the arrival of the grapes at the winery to bottling

Marco Li Calzi | Trainer, consultant, and general manager of Enolfactive

From the moment the grapes arrive at the winery until bottling, wine is exposed to a series of potentially defective compounds that originate at different stages of the production process. This lecture offers a systematic overview of the main off-flavors and the molecules responsible for them, with a practical approach focused on prevention and correction.
Topics covered include: plant-derived compounds from the grapes, such as cis-3-hexenol and IBMP, which cause herbaceous and bell pepper notes; earthy and musty defects linked to Ottenone, MIB, and Geosmin; and Sotolone, associated with Botrytis infections and premature aging. The session will also examine sulfur compounds, including methanethiol (which can be removed via a contact membrane) and 2-acetyltetrahydropyridine (ACTPY), which imparts a “mouse-like” taste. During aging, the session will address DMS, whose sensory impact (which can be either positive or negative) varies significantly depending on concentration, and finally TDN (a petroleum-like odor in aged Rieslings). A technical and practical session to understand the chemical origins of defects and the available intervention strategies.

Speaker Bio
Marco Li Calzi, PhD, has taught Oenology and Sensory Sciences at the University of Missouri (USA) and the École d’Ingénieurs de PURPAN in Toulouse (France). He is currently a trainer, consultant, and Chief Operating Officer (COO) of the company Enolfactive.

Lesson #3 – Microbiologically Caused Defects in Winemaking

Tiziana Nardi | CREA Researcher, Viticulture and Oenology Research Center

The microorganisms present during winemaking—yeasts, bacteria, and contaminants—are among the main sources of olfactory and taste defects in wines. This lecture provides an up-to-date overview of defects of microbiological origin, with a focus on the biochemical mechanisms that lead to the production of the molecules responsible.
Topics covered include: volatile acidity—an old defect (almost) under control—when it can be produced and by whom (non-Saccharomyces at the start of fermentation, Saccharomyces in sluggish fermentations, acetic bacteria, and Brettanomyces if there is oxygen in the wine); FA and off-flavors resulting from nitrogen or sulfur imbalances, including H₂S and overproduction of SO₂; defects related to MLF and yeast-bacteria interactions, with a focus on biogenic amines—including putrescine and cadaverine—and ethyl carbamate; microbial contaminants and associated volatile phenols, primarily Brettanomyces (ethyl phenol, ethyl guaiacol, and the differences with vinyl derivatives); Defects related to microbial consortia (mousy taint—tetrahydropyridines). The course emphasizes the chemical and biological understanding of these processes, complementing the other modules in the program.

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Speaker Bio
Tiziana Nardi holds a degree in Biotechnology and earned her Ph.D. in Viticulture and Enology with the distinction of “Doctor Europaeus” (University of Padua and INRA Montpellier). She completed a postdoctoral fellowship at the University of Burgundy. She is a researcher at CREA-VE and an adjunct professor of Oenological Microbiology at the University of Verona. Since 2021, she has been a member of the OIV’s Microbiology Expert Group. Her research interests include yeasts and lactic acid bacteria, bioprotection of grapes, and the valorization of winemaking byproducts.

Lesson #4 – From the Vineyard to the Consumer: Emerging Factors That Contribute to the Development of Defects

Maria Tiziana Lisanti | University of Naples

Climate change and new market trends are redefining wine production conditions, with direct implications for wine stability and sensory profile. Higher temperatures, water stress, and changes in grape ripening alter the composition of musts, increasing the risk of olfactory defects. At the same time, the reduction in the use of sulfites and the growing demand for low-alcohol wines make wines more susceptible to undesirable sensory deviations.
This session analyzes the main emerging olfactory defects in light of these new production and climatic scenarios, discussing practical prevention and management strategies throughout the entire supply chain. An essential in-depth analysis for anyone who wants to anticipate the challenges of a constantly evolving sector and adapt their winemaking practices to an increasingly complex production environment.

Speaker Bio
Maria Tiziana Lisanti is an Associate Professor of Enology at the University of Naples Federico II. Her research integrates the chemical analysis of odorous compounds with sensory evaluation to study the aromatic profile of wines in relation to production and preservation technologies. Since 2008, she has been a member of the OIV’s “Technology” expert group (Commission II – Oenology), appointed by the Ministry of Agriculture, Food Sovereignty, and Forests.

Lesson #5 – Wine Defects: Bottling and Storage

Maurizio Ugliano | University of Verona

The sensory quality of wine is not limited to the cellar: the bottle is a complex environment in which defects can emerge that compromise the aromatic profile over time. This lecture examines the main issues related to storage, analyzing their chemical, physical, and biological origins as well as possible prevention and correction strategies.
Topics covered include: the mechanisms that trigger wine oxidation; microbiological deviations in the bottle; the appearance of reductive aromatic compounds such as H₂S and mercaptans; atypical aging (UTA) and its impact on the sensory profile; the “light-struck defect” and the conditions that favor its development; TBA and TCA. A concluding module that rounds out the course, offering practical tools to ensure wine quality all the way to the end consumer.

Speaker Bio
Maurizio Ugliano is a Full Professor in the Department of Biotechnology at the University of Verona, where he teaches Oenological Technologies and Processes and Wine Identity and Typicality. His research focuses on the aromatic typicality of wines, stability during storage, and the development of sustainable winemaking techniques. With over one hundred technical and scientific publications, he is included in Stanford University’s list of the Top 2% most influential scientists.

These recordings use AI voice dubbing of the speakers’ original presentations (originals available here: I Difetti dei Vini), used with each speaker’s consent. Some translation discrepancies may occur — the original recordings remain authoritative. Questions? francesca.walmsley@vinidea.it