All still wines contain dissolved carbon dioxide CO2, and in fact, if levels are too low a wine can taste ‘flat’ and appear to lack ‘freshness’.
Recent work at the AWRI has delved deeper into the role of CO2 in still wines – exploring if specific tastes and textures are influenced by CO2 and investigating how other wine components interact with dissolved CO2.
Chardonnay, Viognier, Shiraz and Cabernet Sauvignon wines were prepared with a range of CO2 levels. The pH, alcohol and (in the case of red wines) tannin levels of the wines were also varied in combination with dissolved CO2. The wines were then tasted under conditions that reflected typical wine consumption, with tasters rating a range of flavour and mouth-feel attributes.
Dissolved CO2 concentrations of the wine in the glass were simultaneously measured using a modified Orbisphere system that took ‘parallel’ measurements of dissolved CO2 from replicate wine glasses at the moment the wines were being tasted. This attention to detail was necessary as wine temperature, glass shape, pouring, and the time between pouring and tasting can all affect dissolved CO2 at the moment of tasting, which could in turn influence the taste and mouth-feel.
The trial has been completed and the results to be published shortly will include details of the dynamics of dissolved CO2 losses during pouring and before they are tasted. It will also describe the interactions between dissolved CO2 and the wine matrix on the tastes and textures of white and red wine.