Managing Rose Thiol Character with Fermentation Temperature (2017)

This study examined the impact of increasing fermentation temperature on the chemical, sensory, and thiol attributes of Merlot rose. Merlot grapes were harvested, destemmed, and cold soaked for 1 day, then pressed off into tank. Juice was stabulated in tank for 3-5 days before racking into two separate tanks. The NTU of the juice was adjusted to 200 prior to fermentation. All treatments between the juices and wines were equal, except that the control was fermented at 14°C for the whole fermentation whereas the treatment was fermented at 20°C for the first 4 days, then dropped to 14°C for the rest of fermentation. Wine chemistry was not much affected by the treatments. Hydrogen sulfide and 3-MH were slightly lower in the higher temperature fermentation. 71% of judges were able to distinguish the wines in triangle testing, suggesting a statistically significant difference between the wines (p<0.001). This may have been due to turbidity differences from lees being disrupted in the bottles during pouring. In general, the control wine was preferred. There were no strong trends for the descriptors used in this study. There was a slight tendency for Fruit Intensity, Thiol Aromas, and Overall Aromatic Intensity to be increased by Low Temperature. The High Temperature wine may have had slight reduction relative to the low temperature wine.

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