Identifying the key compounds in grapes that contribute to wine flavour and aroma has been an elusive challenge. CSIRO and our partners have uncovered the genetic and biochemical basis of grape characteristics, and the sensory properties they lend to wines.
Predicting wine style from grape berry measurements
There is a gap in the wine industry’s knowledge of why parcels of grapes from the same variety can result in very different wine sensory outcomes. This means there are no objective measures of grape quality available for grading fruit. Understanding how grape components influence wine style is the first step in developing quality measures - and growing grapes to meet market demand.
Models to predict wine sensory attributes
Science has long played a major role in wine making, and our scientists are investigating the aroma and flavour compounds of wine using sophisticated tools to understand what makes a good wine. By separating the chemicals in a wine or the grapes used for wine making and then identifying what the chemicals are, we can more accurately measure vital compounds in winegrapes.
However, the aroma chemistry in isolation does not explain how fruit composition influences the sensory experience of a consumer.
In collaboration with the University of Adelaide, we are matching metabolomic profiles of grapes with sensory properties of the equivalent wines. From this we have developed models which predict individual wine sensory attributes using five or less grape measures with strong correlations.
We are also exploring the reasons why wines from different varieties can taste so different. For example, methoxypyrazines are compounds responsible for the herbaceous, green, vegetable aromas found in Cabernet Sauvignon or Sauvignon Blanc. By comparing the genetic maps of grape varieties that do not produce these compounds with those which do, our scientists were able to pin down the gene responsible for this character.
Identifying these compounds, and understanding how they are made in the grape berry and how they make it into wine, opens the door to new ways of managing flavour in the vineyard. By objectively measuring grape flavour attributes in the vineyard it’s possible to predict and optimise wine flavour and aroma before the grapes are harvested, improving the efficiency of growing grapes to suit desired wine styles.
This research is carried out by CSIRO and the University of Adelaide with support from Wine Australia.