Monitoring gas-phase CO2 in the headspace of champagne glasses through combined diode laser spectrometry and micro-gas chromatography analysis

Understanding the tasting of champagne and other sparkling wines from a scientific perspective

From uncorking the bottle to the bursting of bubbles in the glass, the science behind the tasting of champagne and other sparkling wine is both traditional and at the forefront of modern developments. The strong interaction between the various parameters at play in a bottle and in a glass of sparkling wine has been the subject of study for around two decades. Indeed, sparkling wine tasting is often seen as the pinnacle of glamor and frivolity for most people, but it should also be considered as a fantastic playground for chemists and physicists to explore the subtle science behind this centuries-old drink, whose prestige today goes well beyond the borders of Champagne and France. This article offers an overview of the physicochemical processes that mark a tasting of champagne or sparkling wine in the broad sense, from the cork popping out of the bottleneck to the formation and bursting of bubbles in your glass, including the choice of the glass and how to serve and drink the wine correctly.

An Infrared Laser Sensor for Monitoring Gas-Phase CO2 in the Headspace of Champagne Glasses under Wine Swirling Conditions

In wine tasting, tasters commonly swirl their glasses before inhaling the headspace above the wine. However, the consequences of wine swirling on the chemical gaseous headspace inhaled by tasters are barely known. In champagne or sparkling wine tasting, starting from the pouring step, gas-phase carbon dioxide (CO2) is the main gaseous species that progressively invades the glass headspace. We report the development of a homemade orbital shaker to replicate wine swirling and the upgrade of a diode laser sensor (DLS) dedicated to monitoring gas-phase CO2 in the headspace of champagne glasses under swirling conditions. We conduct a first overview of gas-phase CO2 monitoring in the headspace of a champagne glass, starting from the pouring step and continuing for the next 5 min, with several 5 s swirling steps to replicate the natural orbital movement of champagne tasters. The first results show a sudden drop in the CO2 concentration in the glass headspace, probably triggered by the liquid wave traveling along the glass wall following the action of swirling the glass.

The Effect of Carbonation Level on the Acceptability and Purchase Intent of Muscadine and Fruit Wines

Carbonation is a value-added process that can affect the mouthfeel, perception of volatile compounds, perception of sweetness, and ultimately if a consumer likes a wine. While much work has been completed on traditional varieties of sparkling wine, little research has been completed on niche market wines such as muscadine and fruit wines, which make up a large percentage of wines produced in the Southeastern USA. The objective of this research was to create and evaluate force-carbonated sparkling wine at five carbonation levels. Five finished wines from Florida wineries were obtained, then assessed for the sugar and alcohol content. Each wine was carbonated and then presented to consumers for sensory evaluation (n = 68–89 per evaluation). The questionnaire assessed the perceived sweetness, preference, liking, purchase intent, and comments of each sample. The data illustrated participants consistently preferred the carbonated samples over the noncarbonated sample. The data indicates a roughly even distribution of preference between the four carbonation levels. The data also showed statistically significant differences between the original wine and the carbonated varieties with respect to liking, preference, and purchase intent, which was supported by the consumer’s comments for the most preferred and least preferred samples. Overall, this research serves to impact the wine industry by identifying how carbonation levels affect the acceptability of niche wine varieties, and allows winemakers to successfully expand, diversify, and increase the product portfolio for wineries.

A Portable Micro-Gas Chromatography with Integrated Photonic Crystal Slab Sensors on Chip

The miniaturization of gas chromatography (GC) systems has made it possible to utilize the analytical technique in various on-site applications to rapidly analyze complex gas samples. Various types of miniaturized sensors have been developed for micro-gas chromatography (µGC). However, the integration of an appropriate detector in µGC systems still faces a significant challenge. We present a solution to the problem through integration of µGC with photonic crystal slab (PCS) sensors using transfer printing technology. This integration offers an opportunity to utilize the advantages of optical sensors, such as high sensitivity and rapid response time, and at the same time, compensate for the lack of detection specificity from which label-free optical sensors suffer. We transfer printed a 2D defect free PCS on a borofloat glass, bonded it to a silicon microfluidic gas cell or directly to a microfabricated GC column, and then coated it with a gas responsive polymer. Realtime spectral shift in Fano resonance of the PCS sensor was used to quantitatively detect analytes over a mass range of three orders. The integrated µGC–PCS system was used to demonstrate separation and detection of a complex mixture of 10 chemicals. Fast separation and detection (4 min) and a low detection limit (ng) was demonstrated.

Recent Progress in the Analytical Chemistry of Champagne and Sparkling Wines

The strong interplay between the various parameters at play in a bottle and in a glass of champagne or sparkling wine has been the subject of study for about two decades. After a brief overview of the history of champagne and sparkling wines, this article presents the key steps involved in the traditional method leading to the production of premium modern-day sparkling wines, with a specific focus on quantification of the dissolved CO₂ found in the sealed bottles and in a glass. Moreover, a review of the literature on the various chemical and instrumental approaches used in the analysis of dissolved and gaseous CO₂, effervescence, foam, and volatile organic compounds is reported.

Unveiling Carbon Dioxide and Ethanol Diffusion in Carbonated Water-Ethanol Mixtures by Molecular Dynamics Simulations

The diffusion of carbon dioxide (CO2) and ethanol (EtOH) is a fundamental transport process behind the formation and growth of CO2 bubbles in sparkling beverages and the release of organoleptic compounds at the liquid free surface. In the present study, CO2 and EtOH diffusion coefficients are computed from molecular dynamics (MD) simulations and compared with experimental values derived from the Stokes-Einstein (SE) relation on the basis of viscometry experiments and hydrodynamic radii deduced from former nuclear magnetic resonance (NMR) measurements. These diffusion coefficients steadily increase with temperature and decrease as the concentration of ethanol rises. The agreement between theory and experiment is suitable for CO2. Theoretical EtOH diffusion coefficients tend to overestimate slightly experimental values, although the agreement can be improved by changing the hydrodynamic radius used to evaluate experimental diffusion coefficients. This apparent disagreement should not rely on limitations of the MD simulations nor on the approximations made to evaluate theoretical diffusion coefficients. Improvement of the molecular models, as well as additional NMR measurements on sparkling beverages at several temperatures and ethanol concentrations, would help solve this issue.

Nanostructured metal oxide semiconductor-based sensors for greenhouse gas detection: progress and challenges

Climate change and global warming have been two massive concerns for the scientific community during the last few decades. Anthropogenic emissions of greenhouse gases (GHGs) have greatly amplified the level of greenhouse gases in the Earth's atmosphere which results in the gradual heating of the atmosphere. The precise measurement and reliable quantification of GHGs emission in the environment are of the utmost priority for the study of climate change. The detection of GHGs such as carbon dioxide, methane, nitrous oxide and ozone is the first and foremost step in finding the solution to manage and reduce the concentration of these gases in the Earth's atmosphere. The nanostructured metal oxide semiconductor (NMOS) based technologies for sensing GHGs emission have been found most reliable and accurate. Owing to their fascinating structural and morphological properties metal oxide semiconductors become an important class of materials for GHGs emission sensing technology. In this review article, the current concentration of GHGs in the Earth's environment, dominant sources of anthropogenic emissions of these gases and consequently their possible impacts on human life have been described briefly. Further, the different available technologies for GHG sensors along with their principle of operation have been largely discussed. The advantages and disadvantages of each sensor technology have also been highlighted. In particular, this article presents a comprehensive study on the development of various NMOS-based GHGs sensors and their performance analysis in order to establish a strong detection technology for the anthropogenic GHGs. In the last, the scope for improved sensitivity, selectivity and response time for these sensors, their future trends and outlook for researchers are suggested in the conclusion of this article.

How Does Gas-Phase CO2 Evolve in the Headspace of Champagne Glasses?

The chemical space perceived by a consumer of champagne or other sparkling wines is progressively modified all along tasting. Real-time monitoring of gas-phase CO₂ concentration was performed, through a CO₂-diode laser sensor, along a two-dimensional array of nine points in the headspace of three types of glasses poured with champagne. Two original glasses with distinct headspace volumes were compared with the standard INAO tasting glass. For each of the three glass types, a kind of temperature-dependent CO₂ fingerprint was revealed and discussed as a function of the glass geometry and headspace volume. Moreover, a simple model was developed, which considers the rate of decrease of the concentration of gas-phase CO₂ in the headspace of a glass after the pouring process as being mainly ruled by natural air convection in ambient air. The timescale which controls the rate of decrease of gas-phase CO₂ was found to highly depend on the ratio of the headspace volume to the open aperture of the glass.

Computational Fluid Dynamics (CFD) as a Tool for Investigating Self-Organized Ascending Bubble-Driven Flow Patterns in Champagne Glasses

Champagne glasses are subjected to complex ascending bubble-driven flow patterns, which are believed to enhance the release of volatile organic compounds in the headspace above the glasses. Based on the Eulerian–Lagrangian approach, computational fluid dynamics (CFD) was used in order to examine how a column of ascending bubbles nucleated at the bottom of a classical champagne glass can drive self-organized flow patterns in the champagne bulk and at the air/champagne interface. Firstly, results from two-dimensional (2D) axisymmetric simulations were compared with a set of experimental data conducted through particle image velocimetry (PIV). Secondly, a three-dimensional (3D) model was developed by using the conventional volume-of-fluid (VOF) multiphase method to resolve the interface between the mixture’s phases (wine–air). In complete accordance with several experimental observations conducted through laser tomography and PIV techniques, CFD revealed a very complex flow composed of surface eddies interacting with a toroidal flow that develops around the ascending bubble column.