Phenolics and spectroscopy: challenges and successful stories in the grape and wine industry.

Phenolic compounds are considered to have a major role in the quality of grapes and wine. These compounds contribute to the sensory perception of red wine as they are involved in astringency and bitterness as well as in determining the colour intensity of grapes and wine (e.g., anthocyanins content). Several techniques are used to characterise and quantify these compounds in grapes and wine samples such as ultraviolet-visible spectroscopy or high-performance liquid chromatography. More recently, different applications and reports have shown the value of vibrational spectroscopy techniques to monitor and measure phenolic compounds along the grape and wine value chain. This article summarises as well as discusses challenges and successful stories in relation to the utilisation of vibrational spectroscopy techniques to measure phenolic compounds in grapes and wine. Specifically, content presented at the workshop 'Outstanding sensors challenge beverage and food future' organised by the Italian Society of Food Science and Technology and the University of Pisa (Pisa, Italy) is summarised. Although vibrational spectroscopy techniques have been proven to be of importance to measure composition across the grape and wine value chain, the adoption of these technologies has been compromised by the accessibility and price of instruments. Understanding the basic principles of the different vibrational spectroscopy methods (e.g., characteristics, limit of detection) as well as how to effectively use the data generated are still main barriers facing the incorporation of these techniques into the grape and wine industry. Furthermore, is still not clear for many users of these technologies how they will contribute to the sustainability of the wine industry as well as to preserve the identity of the wine making process. © 2023 Society of Chemical Industry.