# Pairing Red Wine and Closure: New Achievements from Short-to-Medium Storage Time Assays
## 1 Introduction  
Wine is a relevant beverage across many regions of the world [1], and its sensory characteristics have been the focus of extensive research over time. Sensory attributes are pivotal for determining consumer acceptance, assessing quality, and ensuring authenticity. The study of wine's sensory and physicochemical properties has gained interest in recent years, driven by growing interest from researchers and companies who wish to explore, improve, and adapt wines to align with market trends and innovation demands. The unique physicochemical and sensory profile of wines emerges from a complex interplay of factors, beginning in the vineyard and extending through every stage of winemaking. After bottling, the wine undergoes a period of storage under varying conditions that can significantlyinfluence its characteristics. During this phase, several factors play a role, including the size and material of the closure, the dimensions of the bottleneck and closure, the storage temperature and duration, and the storage positioning of the bottle, among others [2]. Red wines, in particular, undergo notable changes during storage, and their quality is often expected to improve over time. The evolution of red wines is primarily driven by transformations in their phenolic composition, which affect their color, mouthfeel, and oxidation levels. Additionally, wine's volatile composition evolves depending on several factors, with exposure to oxygen being a critical factor. While controlled oxygen levels can contribute positively to the development of aromas and complexity, excessive oxygen can lead to oxidative spoilage [3]. The permeability of closures to oxygen levels plays an important role in modulating wine's sensory properties during storage, influencing its evolution and overall quality [1; 4], with high oxygen transfer rate (OTR) levels accelerating oxidative processes, and low-OTR closures, such as screw caps, creating a reductive environment [5; 6]. Moreover, successful headspace oxygen management at and post-bottling is possible when in-depth knowledge of the impact of bottling and storage on oxygen levels and wine quality is achieved [7]. Most modern bottling lines can achieve displacement of approximately 60-80% of the oxygen from the headspace, resulting in reasonably low headspace oxygen values of around 0.8-1.5 mg/L [8]. There are several types of closures commonly used in winemaking, including natural and micro-agglomerated cork stoppers, and screw cap closures, which represent the focus of the present study. Natural cork stoppers, sourced from the cork oak bark (_Quercus suber_ L), allow moderate oxygen ingress, supporting gradual maturation of the wine and the development of complex sensory attributes [1; 4]. Micro-agglomerated cork stoppers, made from granulated cork particles bonded with food-grade resins, provide a more uniform structure than natural cork [4; 9]. Screw caps, which are typically made of aluminum with an inert liner, create an almost airtight seal, effectively minimizing oxygen ingress, but their prolonged use can sometimes result in reductive conditions, altering the wine's aroma and flavor over time [1; 4; 10]. Previous studies suggest that the type of closure used might play a key role in preserving the quality, shelf life, and evolution of wines, with volatile organic and phenolic compounds being of particular importance [1; 11]. Natural cork stoppers have been shown to better preserve ethyl esters--compounds associated with fruits and sweet aromas--especially over long storage periods. These notes are commonly appreciated by consumers [12; 13; 14; 15]. Conversely, the presence of high amounts of sulfur compounds has been reported more frequently in wines sealed with screw caps, which may explain the reductive aromas (off-flavors) [16; 17; 18]. Some studies, however, suggest that aroma perception is not significantly influenced by the type of closure used [19; 20].