WINETECH Technical Yearbook 2019

Most interestingly, further statistical analysis made it possible to demonstrate that for each cultivar and regardless of the initial wine sensory profiles, the storage conditions had similar effects on the evolution of the wines (with one exception). In other words, even if the wines were described differently, they changed in a similar pattern. with storage, how much they changed (higher or lower), and how the samples are similar based on these attribute changes. ost interestingly, further statistical analysis made it possible to demonstrate that for ach cultivar and regardless of the initial wine sensory profiles, the storage onditions had similar effects on the evolution of the wines (with one exception). In ther words, even if the wines were described differently, they changed in a similar attern. patt rn.

during storage, regardless of the storage temperature. The study demonstrated the applicability of the rapid sensory method (Pivot © Profile) for this type of experiments (comparison to an initial/reference stage/ sample). Moreover, this method was never before used in the evaluation of time-related experiments. Statistical analysis showed that all control (T0) wi es w re very different from the wines after storage, regardless of the initial wine profile. Similar to the chemistry results presented in Part 1, the sensory evolution of the wines was not generally affected by the initial wine profile for all six Sauvignon blanc and six Chenin blanc wine sets included in the project. In other words, in almost all cases the changes ob erved were similar, regardless of how the time 0 wine was perceived. Based on the sensory results, wines stored at higher temperatures for longer were perceived as more ‘toasty’, ‘woody’, ‘oak’ and ‘honey’, while those stored at lower temperature for shorter period were perceived as ‘floral’ and ‘tropical’ in comparison to the initial wine. SUMMARY Wine aroma is susceptible to change during storage, especially at high temperatures. In a recent study at the Department of

Viticulture and Oenology of Stellenbosch University, we investigated changes in South African Sauvignon blanc and Chenin blanc wine sensory profile, volatile composition and antioxidant-related parameters resulting from storage of unwooded wines under different temperatures (room temperature, 15°C and 25°C) and durations (0, 3 and 9 months). Statistical data analysis was used to assess the correlations in the sensory and chemical evolution of the wines relative to the control (time 0). REFERENCES Thuillier, B., Valentin, D., Marchal, R. & Dacremont, C., 2015. Pivot © Profile: A new descriptive method based on free description. Food Quality and Preference 42: 66-77. DOI: 10.1016/j.foodqual.2015.01.012. Makhotkina, O., Pineau, B. & Kilmartin, P.A., 2012. Effect of storage temperature on the chemical composition and sensory profile of Sauvignon blanc wines. Australian Journal of Grape and Wine Research 18(1): 91-99. DOI: 10.1111/j.1755-0238.2011.00175.x. Pérez-Coello, M.S., González-Viñas, M.A., Garcia-Romero, E., Diaz-Maroto, M.C. & Cabezudo, M.D., 2003. Influence of storage temperature on the volatile compounds of young white wines. Food Control 14(5): 301- 306. DOI: 10.1016/S0956-7135(02)00094-4.

FIGURE 3. General changes in the aroma attributes with storage.

Spanish study found significant increases in buttery, ripe and spicy attributes and decreases in fruity, fresh and floral attributes with higher storage temperatures. In our study, only one winery’s SB sample set was an exception as the control had particularly higher ‘pineapple’, ‘green’ and less ‘fruity’ notes compared to the other wineries. ‘Fresh’ remained relatively unchanged, with only some wineries’ sample sets showing a slight decrease with higher temperature and longer storage times. Most interestingly, further statistical analysis made it possible to demonstrate that for each cultivar and regardless of the initial wine sensory profiles, the storage conditions had similar effects on the evolution of the FIGURE 3. General changes in the aroma attributes with storage. The exception ca possibly be explained by the fact that the thiol and colour parameters for that sample set were also different from the other wineries. In other words, the chemical composition of the wines influenced 1) how the wines were perceived and 2) how the wines changed during storage. Take home message T is is the fi st time that a pa all l stud was one on S uvignon blanc and Chenin blanc storage effects. The results showed that time played the most important role during storage, regardless of the storage temperature. The study demonstrated the applicability of the rapid sensory method (Pivot © Profile) for this type of experiments (comparison to an initial/reference stage/sample). Moreover, this method was never before used in the evaluation of time-related xperiments. Statistical analysis showed that all control (T0) wines were very different from the wines after storage, gardless f he initial wine profile. Simi ar to the chemistry results presented in Part 1, the sensory evolution of the wines was not generally FIGURE 3. Gener l changes in the aroma attributes with storage. he exception can possibly be explained by the fact that the thiol and colour arameters for that sample set were also different from the other winer es. I ords, the chemical composition of the wines influ nced 1) how the win s w re erceived and 2) how the wines changed during storage. ake home message his is the first time that a parallel study was done on Sauvign n blanc and Chenin lanc storage effects. The results showed that time played the most important role uring storage, regardless of the storage temperature. The study demonstrated the pplicability of the rapid sensory method (Pivot © Prof le) for this type of xperime ts comparison to an initial/reference stage/sample). Mor over, this method was never efore used in the evaluation of time-related experiments. tatistical analysis showed that all control (T0) wines were very different from the ines after storage, regardless of the initial wine profile. Similar to the ch mistry esults presented in Part 1, the sensory evolution of the wines was not generally FIGURE 3. General changes in the aroma attributes with stor ge. The exception can possibly be explained by the fact that the thiol and colour parameters for that sample set were also different from the other wineries. In other words, the chemical composition of the wines influenced 1) how the wines were perceived and 2) how the wines changed during storage. Take hom message This is the first time th t a parallel study was done on Sauvignon blanc and Chenin blanc storage effects. The results showed that time played the most important role during storage, reg rdl ss of the storage temperature. The study demonstrated the applicability of the rapid sensory method (Pivot © Profile) for this type of experiments (comparison to an initial/reference stage/sample). Moreover, this method was never before used in the evaluation of time-related experiments. Statistical analysis showed that all control (T0) wines were very different from the wines after storage, regardless of the initial wine profile. Similar to the chemistry results presented in Part 1, the sensory evolution of the wines was not generally wines (with one exception). In other words, even if the wines were described differently, they changed in a similar pattern. The exception can possibly be explained by the fact that the thiol and colour parameters for that sample set were also different from the other wineries. In other words, the chemical composition of these wines influenced 1) how the wines were perceived and 2) how the wines changed during storage. TAKE-HOME MESSAGE This is the first time that a parallel study was done on Sauvignon blanc and Chenin blanc wine storage effects. The results showed that time played the most important role

– For more information, contact Astrid Buica at abuica@sun.ac.za.