Comparison of consecutive harvests versus blending treatments to produce lower alcohol wines from Cabernet Sauvignon grapes: Impact on wine volatile composition and sensory properties

Comparison of water addition and early‐harvest strategies to decrease alcohol concentration inVitis viniferacv. Shiraz wine: impact on wine phenolics, tannin composition and colour properties

“…This study compared two strategies for alcohol reduction in red winemaking, early‐harvest and water addition to must, using phenolic outcomes in the wine as a potential indicator of quality loss or gain. Previous studies using a juice substitution approach to dilute Cabernet Sauvignon and Merlot, in which no change in the grape solids (seeds, pulp and skin) to must volume ratio occurred during fermentation, showed that alcohol could be effectively reduced by water addition with no adverse effect on wine phenolics (Casassa et al , Schelezki et al ,b). Given that Shiraz is a key red grape cultivar produced in Australia, it was of relevance to observe whether a similar outcome could be achieved.…”

“…Given that Shiraz is a key red grape cultivar produced in Australia, it was of relevance to observe whether a similar outcome could be achieved. To build on previous work (Harbertson et al , Casassa et al , Schelezki et al ,b) the mode of water addition was also compared, including both a direct addition, and a standard juice substitution approach. The results of the current study indicated that the concentration of phenolics and tannin was significantly lowered relative to that of the H‐3 Control by all the water addition treatments both at the end of fermentation (Table ) and after losses of phenolic material had occurred at the end of MLF (Table ).…”

“…In light of this, lowering wine alcohol by using either early harvest or water addition might be considered relevant to the preservation of a desirable wine hue. Considering that the ‘early harvest’ treatments applied in the current study would constitute ‘ideal’ commercial harvests points in Australia for wine alcohol targets, it is also important to assess the potential benefit of delaying harvest as a means to increase the phenolic potential (extractable tannin and anthocyanin) of the grapes, against possible losses associated with overripe fruit, such as yield losses, disease incidence or negative sensory attributes (Nair et al , Coombe and McCarthy , Schelezki et al ,b). In terms of yield loss, the small berry mass loss from H‐2 to H‐3 (Table ) observed for the Shiraz vineyard studied could result in up to 13% potential wine volume loss, based on a 66% extraction rate.…”

“…A clear alternative to lower wine alcohol is simply to harvest the fruit earlier. This tends to be avoided for grape cultivars where ‘vegetative’ or ‘green’ characters are often attributed to the wines produced from grapes harvested earlier, and where delaying harvest results in increased ‘dark fruit’ attributes (Bindon et al , Schelezki et al ). This is because after veraison, the concentration of some less desirable compounds such as methoxypyrazine decrease during ripening, while compounds positively associated with desirable grape attributes such as anthocyanin and tannin, as well as important volatile compounds (and their precursors), may continue to increase (Coombe and McCarthy , Bindon et al ).…”

“…Several unknowns exist for the water addition process following changes in Australian regulations (Food Standards Australia New Zealand ) which allow water to be added to must. Studies have been conducted for Vitis vinifera cultivars Cabernet Sauvignon and Merlot, whereby must was runoff after crushing and an equivalent volume of water added (juice substitution) to decrease the alcohol concentration of finished wines, with no significant change to wine tannin concentration or colour (Casassa et al , Schelezki et al ,b). These results indicated potential benefits of water addition to reduce alcohol but needed to be confirmed for Shiraz, the principal grape cultivar grown in Australia.…”