This study examines the impact of cold soaking vs extended maceration on Petit Verdot wine, with maceration time being equal between treatments. The goal was to have on treatment spend more time exposed to an aqueous phase, with the other treatment having more time exposed to an alcoholic phase. Petit Verdot grapes from the same vineyard block were harvested on the same day and destemmed into two separate T Bins. One T Bin underwent a 4 day cold soak prior to inoculation, whereas the other was immediately inoculated without cold soak. Both treatments underwent a 25 day maceration before being pressed off on the same day: thus, the cold soak received less time in contact with must in an alcoholic phase. All other treatments between wines were identical. Wine chemistry and ester profiles were not much different between treatments. The extended maceration treatment had higher levels of color, epicatechin, and tannin, but other phenolic compounds were not much different. The wines were not found to be significantly different via triangle testing. However, there was a strong trend for the cold soak wine to have higher Astringency than the extended maceration wine. There was a slight tendency for this wine to have increased Bitterness and lower Body as well. The total maceration time for these wines was long in both cases, and as such the differences seen here may be greater if smaller overall maceration times are used. In the future, this should be performed, and more microbial analysis should be performed as well.
Cabernet Franc was fermented in three separate ways. The control received no cold soak nor extended maceration. One wine was fermented in the Maceration a Chaud du Marc style, where fermenting juice was racked into another tank where the temperature was kept around 20C (70F), the skin was left in the Tbin and temperature was brought up to 42C (107F) until the juice reached a specific gravity of 1.020 and was blended back with the skin. The third wine received both a cold soak and extended maceration. No chemical differences were observed between wines, except that the wine with cold soak and extended maceration had higher pH, lower TA, and lower ethanol. Maceration a Chaud du Marc slightly increased polymeric pigment and color, and slightly decreased hue. People tended to prefer the Maceration a Chaud du Marc, in spite of being described of having some typical Brettanomyces aromas.
Two different Merlot clones (181 and 343) were evaluated for chemical and sensory differences due to cold soaking. Not much color difference was observed between wines that had undergone cold soak compared to controls. However, significant sensory differences existed between wines, with most people preferring cold soaked wines.