Aeration ofVitis viniferaShiraz fermentation and its effect on wine chemical composition and sensory attributes

Abstract

Background and Aims Aeration during fermentation of red wines has the potential to enhance positive red fruit attributes and suppress less desirable reductive characteristics. The implementation of aeration in commercial winemaking, however, is impeded by the lack of a clear understanding of both the major benefits of its use and the nature of the aeration regimes required to modify the finished product. This work aimed to evaluate the impact of different modes of aeration, varying in their timing, duration and intensity, on fermentation duration, chemical composition and sensory properties of Shiraz wine. Methods and Results Forty‐eight pilot‐scale fermentations (450 kg) were treated with different aeration modalities and compared to non‐aerated fermentations across four vintages. This work demonstrated the reproducible effects of aeration, resulting in an enhancement of fruit‐related attributes, decreases in colour intensity and a lowering of astringent mouthfeel and bitterness. The development of attributes describing possible oxidation or undesirable volatility were not observed in this work. These effects on wine sensory attributes were correlated with an increase in the concentration of relevant short and branched‐chain esters and acetates, and a decrease in the concentration of phenolic substances. No enhancement of fermentation performance was observed in any of the trials. Overall, this work revealed the robustness of red wine fermentations to aeration. Conclusions This work provides strong evidence that aeration does not alter the duration of either alcoholic or malolactic fermentation of red musts. Although there was no impact on fermentation performance, aeration did result in the production of wines with increased red fruit characters, and decreased astringency and reductive off‐odours. Significance of the Study This work demonstrates aeration to be a useful oenological tool for the production of red wine and indicates that stylistic impact, rather than fermentation performance, is likely to be more pertinent to the adoption of red wine aeration.

Modulation of Volatile Thiol Release during Fermentation of Red Musts by Wine Yeast

“…A post-hoc Tukey test was calculated at a 95% confidence level for attributes showing statistical evidence to have differed across strain effect using the judge by treatment error term. To explore and model the relationships between wine composition and sensory data of the treatment fermentation replicates, Partial Least Squares Regression (PLS-R) was conducted similarly to that described in Day, et al [40]. Briefly, chemical variables (x's) and sensory responses (y's) were standardised, full cross-validation was performed, and the NIPALS algorithm was used with 30,000 iterations calculated.…”

Effect of Aeration on Yeast Community Structure and Volatile Composition in Uninoculated Chardonnay Wines

“…Oxygen management, which includes oxygen exclusion or air addition, is an important tool in winemaking, where it can be used to modify wine aroma, flavor and mouthfeel, and influence wine style [54,55]. Air addition has been shown to increase yeast viability and improve fermentation efficiency [22][23][24][25], at least in white wine production.…”

Mechanisms of the initial stage of non‐enzymatic oxidation of wine: A mini review

“…The concentration of acetate acid was only found to reach 0.84 g/L in the long, higher intensity aerations (total oxygen exposure 20.4 and 49.3 mg L −1 h −1 ). In the same trial, ethyl acetate reached 81 and 102 mg/L compared to Control trial (48 mg/L for no oxygen exposure treatment) (Day et al., 2021).…”

“…Increasing the redox potential by introducing air during Cabernet Sauvignon wine fermentation at different scales (100‐10,000 L) seems to alleviate the negative sensory characteristics of wines caused by too low reduction potentials, such as hydrogen sulfide (Nelson et al., 2023). In a fermentation study of Shiraz wines, it was found that within the aeration scope studied, not only reductive odors were reduced, but red fruit characteristics were also increased (Day et al., 2021). When the wine is exposed to air, the oxygen concentration is about ∼8 mg/L at room temperature.…”