Grapevine & Wine 06/02/2012

What is the wine body?

Wine body plays an important role in the overall mouthfeel of wine along with other mouthfeel sensations such as astringency, warming and carbonation. A new research shows key coistituents

Several, sometimes overlapping, sensory and physical measures have been identified to describe wine body.
Much research work characterizing the “body” aspect of mouthfeel has focused on correlating the viscosity of the liquid to a combination of sensory attributes used to describe this property.
Specific experiments studying the relationship between the rheological properties of wine and its body style have led to a partial understanding of how a few chemical constituents influence this sensory quality. Noble and Bursick estimated that the viscosity threshold difference, the minimum difference in viscosity between two wines so that at least 75% of a trained tasting panel can correctly determine which one has the higher viscosity, was 0.141 mPa s at 20C.
Noble and Bursick also showed that glycerol additions of approximately 25 g/L, which are in excess of that typically observed in table wine, can lead to statistically significant differences in perceived viscosity. Sucrose has also been shown to modify the viscosity of a wine.
Amerine and Roessler suggested that ethanol played a role in influencing wine body, typically increasing body with increasing alcohol content.
The last research on this argument is by Ronnebaum and takes a different approach by hypothesizing that the wine body sensation could be influenced by a combination of both chemosensory and mechanosensory attributes that are a result of multiple physical and chemical properties of the wine. This exploratory research has been structured to measure two key macroscopic chemosensory and mechanosensory variables (e.g., osmotic potential and viscosity, respectively), as well as 23 additional chemical constituents and physical properties of the wines, and to model the results. The chemical constituents were chosen to be those often measured in wines but whose role in wine body style has yet to be determined. Hypotheses relating the connection between these compounds and wine body exist in a few instances, but the majority of the compounds were measured and analyzed for exploratory purposes to correlate them with wine mouthfeel property. The intended result is to generate new ideas as to which wine constituents might be influencing wine body, and thus spur future research into this important area of wine appreciation.
Multivariate statistical modeling was used to identify significant correlations between several chemical constituents and physical properties of wine and its perceived body or viscous mouthfeel. Seventeen white wines that span an anecdotal range of perceived viscous mouthfeel, including Chardonnay, Viognier, Pinot gris, Riesling and Sauvignon blanc, were assessed using a descriptive analysis technique to determine quantitative ratings of viscous mouthfeel. These wines were also submitted to a wide range of chemical constituents and physical property analyses, including viscosity, density and concentrations of ethanol, total phenolics, organic acids (lactate, citrate, tartrate, malate, succinate), glycerol, sugars (fructose and glucose), total extract, and several inorganic anions and cations.
The multivariate statistical model shows that the viscous mouthfeel of these white wines is significantly correlated with physical properties, such as viscosity and osmotic potential, chemical properties, such as lactate and total extract. This work is also consistent with previously published results from other researchers indicating that ethanol and glycerol do not significantly contribute to viscous mouthfeel.

di Aliona Avduhova