Trends in the composition of Australian wine 1984-2014

Abstract

Data for wines from the 2004-2014 vintages were collated from the database of analytical results of The Australian Wine Research Institute's Commercial Services Group and are reviewed in the context of historical trends in wine composition. Data for those 11 vintages were generated from 24 066 commercially bottled Australian table wines (8384 white and rosé wines, and 15 682 red wines), which were submitted to The Australian Wine Research Institute for analysis required to comply with the export/import requirements of destination countries. The wines include multiple vintages of a broad cross-section of Australian wines from commodity to icon status, and producers of all sizes. The wines represent a broad geographical and cultivar spread, with the proportion of wines of each cultivar strongly correlating with the planted vineyard area. The data relate to the compositional variables: alcohol, glucose plus fructose, total dry extract excluding alcohol, sugar and volatile acidity (TDE), titratable acidity at pH 8.2, pH, free sulfur dioxide (SO2), total SO2, bound SO2, and the ratio of free to total SO2. Certain previously identified year-on-year trends have continued, and in some cases appear to have accelerated in the most recent vintages, particularly with increasing glucose plus fructose concentration and pH in red wines. In other cases, previously identified trends appear to have gone into reverse, notably the rise in alcohol concentration in red wines, and for a period, rising TDE in red wines, and one new trend in red wines is apparent, namely decreasing titrable acidity. There is some indication that new trends are also apparent with white and rosé wines, namely decreasing alcohol, increasing glucose plus fructose, increasing pH and an apparent downward shift in TDE, although ANOVA indicates little statistical significance in those trends. Data related to the concentration of SO2 demonstrate upward trends in free SO2 for white and rosé, and red wines. This has occurred with a concurrent decrease in the concentration of total SO2 in red wines for the most recent vintages, leading to a consequent rise in the ratio of free to total SO2. A rise in the ratio of free to total SO2 is also seen in white and rosé wines due to increasing free SO2 concentration. Overall white and rosé wines display fewer upward or downward trends compared with that of red wines, but greater year-on-year variability in the data.

Resveratrol, phenolic antioxidants, and saccharides in South American red wines

“…High values of fructose, as observed in some wines, possibly indicate an early halting of the fermentation, or possibly, a late dosage of grape juice or pure saccharose. We noticed that an increasing trend in remaining saccharides in red wines has been observed in Australian wines, 30 from an average of 0.5 g/L in 1984 to about 2 g/L in 2014 (counted as glucose plus fructose). However, individual wines scatter up to about 35 g/L.…”

Post‐veraison trimming slow down sugar accumulation without modifying phenolic ripening in Sangiovese vines

“…This results in earlier harvest dates, 9 fast grape ripening, excessive sugar accumulation in berries, and resulting high-alcohol wines. 3,10,11,[12][13][14][15] Keller 16 shows that, in many cases, these phenomena have also been coupled to faster depletion of organic acids, high pH, and atypical green flavors in the grape because of the shortening ripening period and the shift towards the hotter part of the season.…”

Manipulation of ripening via antitranspirants in cv. Barbera (Vitis vinifera L.)

“…Over the last decade a trend towards earlier grape ripening marked by excessive and/or overly fast berry TSS accumulation and detrimentally high alcohol concentration in the resulting wine has been reported in several countries (Duchene and Schneider , Godden and Gishen , Keller , Schultz and Jones , Jones ). In many instances, and regardless of cultivar, these phenomena have also been coupled with unacceptably low total acidity (TA), high pH and atypical grape flavours shifting towards overripe and jammy attributes (Keller ).…”

“…Growers in warm areas observe that although optimum grape alcohol is already present by mid‐August in many seasons, full colour and desirable typical attributes continue to lag. Yet delaying harvest to allow for full colour development appears to be a self‐defeating strategy because a further increase in alcohol concentration will likely ensue (Godden and Gishen , Sadras and Petrie ). Such a postponement will also increase the risk of incomplete or sluggish malolactic fermentation (Graca da Silveira et al.…”