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This work investigated Syrah producers' conceptualisation of peppery wines from two different wine regions. For the study, a long-term memory approach was used; in addition, the effects of the region of origin, as well as the sensitivity of the participants to detect rotundone, were evaluated. A total of 101 winemakers from the Northern Rhone Valley (NRV) and Languedoc-Roussillon (LR) were interviewed face-to-face after they had participated in two 3-alternative forced tests to assess their ability to detect rotundone. As part of the interview, participants were asked to remember the last peppery red wine they had tasted, to provide technical information about that wine and, more generally, about practices enhancing this character in wine, and to give their overall appreciation of such peppery notes. Only minor differences were observed between participants with either low or high sensitivity to rotundone; in contrast, an important regional effect on the conceptualisation of peppery notes was observed. Experts from the NRV recognised this character as a marker of wines made from under-ripe grapes. Overall, they perceived this flavour as a positive attribute, notably at a moderate level, but some experts also perceived it negatively. For LR participants, peppery notes were associated with powerful, full-bodied wines from very ripe grapes produced in the South of France and were notably perceived as a positive character. Our results are particularly relevant for the wine community as they show that the conceptualisation of a given wine aroma characteristic by winemakers can strongly differ according to their region of origin.

Smoke taint in grapes and wine is complicated. If a vineyard is exposed to smoke, there are a whole range of factors that determine whether or not the wine eventually made from those grapes will be smoke-affected and to what degree. While many of those factors are now quite well understood (Coulter, 2022; Parker et al., 2023), questions still remain about what consumers think. Do they notice smoke characters in wine? Do they like or dislike them? How strong do smoke characters need to be to cause a reaction in consumers? And are all consumers the same when it comes to smoky wines? Three recent consumer sensory studies at the AWRI aimed to learn more about the answers to these questions. This article presents a summary of the results and conclusions of this work. Full details were recently published by Bilogrevic et al. (2023) as an open access article in the peer-reviewed journal, OENO One (https://doi.org/10.20870/oeno-one.2023.57.2.7261).

When vineyards and grapes are exposed to smoke from wildfires or controlled burns, this can result in wines with smoky, burnt or ashy attributes that have been linked to the presence of elevated concentrations of volatile phenols and phenolic glycosides. These smoky flavours are considered undesirable by winemakers, but there is little information about how consumers respond to smoke-affected wines. To investigate whether consumers respond negatively to smoky attributes when wine is tasted blind, three studies assessing sets of Pinot noir rosé, Chardonnay and unoaked Shiraz wines with varied smoke flavour were conducted. Overall, wines rated high in smoke flavour were less liked compared to non-smoke-affected wines. Independent of wine type, there was a strong negative correlation between smoky flavour and overall consumer liking. Detailed data analysis revealed that consumers who are wine drinkers fell into one of three categories: highly responsive to smoke, moderately responsive, or a smaller group of non-responders. This consumer-based information is essential for guiding the assessment of risk from smoke exposure of grapes and potential for quality defects in wine, as well as identifying and benchmarking management options for wine producers, not only in Australia, but globally.

Background and Aims. A wide range of Chardonnay styles exist on the market, from fruit-forward examples to wines displaying “empyreumatic” aromas such as flint, smoky, mineral, and struck-match. The thiols 2-furylmethanethiol and phenylmethanethiol have been linked to these aromas, and this study aimed to determine the contribution of these compounds to specific sensory properties in Chardonnay wines, as well as the consumer acceptance of wine displaying “empyreumatic” aromas. Methods and Results. Twenty-four Australian and New Zealand Chardonnay wines were selected for volatile analysis and quantitative sensory descriptive analysis. Consumer liking of a subset of six wines was also determined, and a further sensory study involving additions of the thiols to a base wine was conducted. Partial least squares regression showed that flint/struck-match/mineral aromas were related to 2-furylmethanethiol concentration with phenylmethanethiol less well associated. The odorant addition study confirmed that 2-furylmethanethiol directed flint/struck-match/mineral aromas and exerted strong suppression of other aromas while phenylmethanethiol played a lesser role. Consumer acceptance (n = 92) was overall lower for wines displaying high flint/struck-match/mineral aromas, although cluster analysis of the liking scores identified a sizeable consumer group (33%) who preferred wines with this attribute. Conclusions. The potent thiol 2-furylmethanethiol was indicated to be the primary contributor to flint/struck-match/mineral aromas in Chardonnay wines, with phenylmethanethiol playing a subordinate role. Significance of the Study. Increased concentration of 2-furylmethanethiol and the conferred “empyreumatic” odours should be carefully considered when producing wine styles to appeal to consumers.

Wine grapes exposed to smoke and wine made from grapes exposed to smoke can robustly be identified through their elevated concentrations of volatile phenols and phenolic glycosides serving as smoke markers, compared to concentrations typically found in non-smoke-exposed samples. Smoke-affected wines with high concentrations of volatile phenols and glycosides can have smoky flavours, but the relationship between concentrations of specific smoke markers in grapes and the intensity of smoky sensory attributes in the resulting wine has not been established. This study sought to determine whether volatile phenols and glycoside concentration in grapes and wine are suited to predict smoke flavour, to identify the key drivers of smoke flavour in both matrices. The study aimed to determine what concentrations of volatiles and glycosides in grapes impart an unacceptable smoke flavour in the resulting wine, to provide a guide for producers assessing suitability of smoke-exposed grapes for wine production. During vintage 2020, a total of 65 grape samples were collected from vineyards exposed to bushfire smoke, as well as unaffected vineyards. Chardonnay, Pinot Noir, and Shiraz grapes were harvested from vineyards in New South Wales, South Australia, and Victoria. Unoaked wines (50 kg scale) were produced under controlled conditions. The wines had a wide range of smoke flavour intensities rated by a trained sensory panel. Statistical models based on guaiacol, o-cresol, m-cresol, p-cresol, and some glycosides gave good predictions of smoke flavour intensity, with a slightly different optimal model for each cultivar. Subsequently, critical concentrations for quality defects were estimated to provide a guide for producers. A subset of smoke exposure markers in wine grapes affected by smoke from bushfires can be used to predict the degree of smoke flavour in wine. This information provides a first guide for assessing the risk of producing smoke tainted wine from smoke-exposed grapes.

Photoselective shading is a process that modulates the radiation intensity in specific regions of the electromagnetic spectrum. It is a common practice in horticulture to manipulate specific plant physiological responses, but to date has only received minimal attention in viticulture. The potent odorant 1,1,6-trimethyl-1,2-dihydronaphthalene (TDN) is of particular relevance for aged Riesling wine, which are also known to be impacted by the magnitude of bunch zone light exposure during berry development. Hence, in this study, the effect of photoselective bunch zone shading on the formation of TDN in wine was investigated across two consecutive growing seasons. Applying red, black or green shade cloth (SC) to the bunch zone provided unique bunch zone light environments and yielded distinct differences in grape and wine composition compared with the unshaded control. Overall, bunch zone shading through shade cloth was effective in reducing overall photosynthetically active radiation compared to the control and the photoselectivity of the SC treatments differently affected a number of grape and wine measures. Fruit yield was somewhat but not significantly lower under black SC treatments, while juice pH was increased in grapes grown under green and black SC across both vintages compared to the control. Both grape sugar accumulation (P = 0.035) and ammonia nitrogen (P = 0.043) showed evidence of treatment effects, although with low F-statistics (4 and 3, respectively). Measures of hydrolytically released TDN in juice and free TDN concentrations in wine were lower in SC treatments. Unexpectedly, sensory descriptive analysis of the wines demonstrated that increased ‘kerosene-like’ aroma was not consistently associated with free TDN concentrations in wine. In summary, photoselective bunch shading was demonstrated to be an effective method for manipulating grape and wine outcomes and may aid in overcoming viticultural obstacles and quality impacts associated with climate change.