## 3 Results
### Frontenac Gris White Wine Aroma Analysis by SPME-GC-MS-O  
White wines from Frontenac gris grapes had 35 recorded aroma events across all samples. Aromas of \"honey, caramel, butterscott\" and \"strawberry, honey\" had no variation in odor dilution (OD, defined in Methods) and were not used in the multivariate analysis. The aromas with the highest intensity in the Frontenac gris wines were \"banana\", \"fruity 2\", \"honey\", and \"unknown neutral 1\". Cluster summary analysis of OD showed that \"rotten eggs, sulfury\" and \"unknown neutral 1\" were the most representative aromas in these Frontenac gris wine. A \"rotten eggs\" smell in wine is considered a wine fault due to the winemaking process and therefore not considered a characteristic aroma of the grape. A chromatographic peak was not present at the corresponding retention time for \"unknown neutral 1\". As pH and sugar accumulation in the berry increased, key odor-active compounds in these Frontenac gris wines developed from \"unknown neutral 2\" and \"fruity 1\" to \"rose 1\" (Figure 3). These correspond to mass spectral matches of \"unknown neutral 2\" to decanoic acid (CAS 334-48-5) and \"fruity 1\" to ethyl methylbutyrate (CAS 7452-79-1). A suitable mass spectral match \begin{table}
\begin{tabular}{c c c c} \hline \hline
**Cultivar** & **Berry \({}^{\circ}\)Brix** & **Berry pH** & **Aroma Descriptors (Weighted Intensity \({}^{1}\))** \\ \hline \multirow{3}{*}{Frontenac gris} & \multirow{3}{*}{19.5} & \multirow{3}{*}{3.00} & unknown pleasant (19), floral/fruity (11), floral (5), overripe \\  & & & (3), butterscott (2), tomato (1), unknown pleasant 1 (0), \\  & & & unknown neutral 2 (0) \\ \hline \multirow{3}{*}{Frontenac gris} & \multirow{3}{*}{23.1} & \multirow{3}{*}{3.06} & honey/caramel/butterscott (431), fruity (419), cut \\  & & & grass/fruity (417), alcoholic (391), banana (382), body odor \\  & & & (359), fruity 1 (345), solvent (337), unknown pleasant (324), \\  & & & rose 2 (321), garlic (207), carrots/woody (178), cereal (152), \\  & & & honey (122), vinegar (57), woody 1 (55) \\ \hline \multirow{3}{*}{Frontenac gris} & \multirow{3}{*}{23.6} & \multirow{3}{*}{3.18} & strawberry (524), strawberry/honey (395), sweaty (384), \\  & & & fruity 2 (244), match/sulfur (183), rose 1 (132), fecal (117), \\  & & & woody 2 (102), rotten eggs/sulfury (78), mushroom (63), \\ \hline \multirow{3}{*}{Brianna} & \multirow{3}{*}{15.4} & \multirow{3}{*}{3.09} & rose (158), body odor (123), barnyard (122), butterscott 2 \\  & & & (115), unknown pleasant (111), unknown neutral 2 (98), \\  & & & matchstick (92), mint (67), cotton candy (13) \\ \hline \multirow{3}{*}{Brianna} & \multirow{3}{*}{17.6} & \multirow{3}{*}{3.19} & alcoholic (420), overripe fruit 2 (373), rotten eggs (106) \\  & & & strawberry 2 (579), fruity 3 (506), cut grass (500), floral/fruity (472), honey/caramel (468), banana (467), overripe fruit 1 \\ \multirow{3}{*}{Brianna} & \multirow{3}{*}{18.6} & \multirow{3}{*}{3.29} & (455), solvent (425), strawberry 1 (382), unknown neutral 3 \\  & & & (363), fruity 2 (316), garlic (239), unknown pleasant (193), \\  & & & fruity 1 (21), floral (5) \\ \hline \multirow{3}{*}{Brianna} & \multirow{3}{*}{19.6} & \multirow{3}{*}{3.45} & tomato 2 (196), unknown neutral 4 (194), unknown neutral 5 \\  & & & (180), tomato 1 (179), unknown neutral 1 (59), fruity 4 (45), \\ \cline{1-1}  & & & butterscotch 1 (3) \\ \hline \hline \end{tabular} \({}^{1}\) Defined in the Materials and Methods (Section 2.6).  
\end{table} 
Table 3: Summary of the ranked weighted intensity of aromas (recorded by olfactometry) in wine made from Frontenac gris and Brianna grapes harvested at different stages of ripening. All juice was brought to 24 \({}^{\circ}\)Brix for Frontenac gris and 20 \({}^{\circ}\)Brix for Brianna prior to fermentation to ensure similar alcohol content in the wines from the different time points.