Climate and variety impact cold soak effectiveness

Page last updated: Monday, 14 September 2020 - 10:26am

Results

Colour

Table 1 shows the colour analysis of the wines at two time periods; two months after bottling (T1) and nine months after bottling (T2). A percentage of difference is used to indicate the degree of influence the cold soak treatment has when compared to the control.

Hot Shiraz

Control

Cold Soak

% difference

Colour density T1

7.75

6.76

-12.77

Colour density T2

7.86

6.72

-14.45

Colour  hue T1

0.72

0.77

7.91

Colour  hue T2

0.69

0.75

7.97

Total phenolics (a.u.) T1

42.43

37.48

-11.67

Total phenolics (a.u.) T2

41.25

36.00

-12.74

Total anthocyanins (mg/L) T1

265.32

210.92

-20.5

Total anthocyanins (mg/L) T2

197.89

158.75

-19.78

Cool Shiraz

Control

Cold Soak

% difference

Colour density T1

9.11

9.67

6.22

Colour density T2

8.35

8.84

5.87

Colour  hue T1

0.56

0.58

3.57

Colour  hue T2

0.60

0.62

2.5

Total phenolics (a.u.) T1

39.93

41.08

2.87

Total phenolics (a.u.) T2

35.85

36.70

2.39

Total anthocyanins (mg/L) T1

494.64

491.56

-0.62

Total anthocyanins (mg/L) T2

342.53

341.57

-0.28

Hot Cabernet

Control

Cold Soak

% difference

Colour density T1

4.41

5.68

28.9

Colour density T2

3.95

5.72

44.81

Colour  hue T1

0.82

0.73

-10.2

Colour  hue T2

0.69

0.74

6.52

Total phenolics (a.u.) T1

32.06

31.01

-3.25

Total phenolics (a.u.) T2

28.67

29.89

4.24

Total anthocyanins (mg/L) T1

255.99

246.73

-3.62

Total anthocyanins (mg/L) T2

171.50

188.82

10.1

Cool Cabernet

Control

Cold Soak

% difference

Colour density T1

8.64

8.95

3.59

Colour density T2

8.77

8.07

-8.04

Colour  hue T1

0.63

0.61

-3.7

Colour  hue T2

0.67

0.65

-2.26

Total phenolics (a.u.) T1

34.92

36.20

3.68

Total phenolics (a.u.) T2

32.37

32.31

-0.17

Total anthocyanins (mg/L) T1

429.55

432.45

0.68

Total anthocyanins (mg/L) T2

297.55

295.76

-0.6

Hot Merlot

Control

Cold Soak

% difference

Colour density T1

6.74

7.30

8.31

Colour density T2

6.66

7.41

11.34

Colour  hue T1

0.74

0.74

0

Colour  hue T2

0.73

0.75

2.76

Total phenolics (a.u.) T1

39.06

37.48

-4.05

Total phenolics (a.u.) T2

36.96

37.46

1.37

Total anthocyanins (mg/L) T1

310.06

249.07

-19.67

Total anthocyanins (mg/L) T2

263.22

210.19

-20.15

Cool Merlot

Control

Cold Soak

% difference

Colour density T1

7.91

7.36

-6.95

Colour density T2

7.05

6.79

-3.76

Colour  hue T1

0.58

0.60

2.29

Colour  hue T2

0.63

0.65

3.2

Total phenolics (a.u.) T1

33.54

33.24

-0.9

Total phenolics (a.u.) T2

29.84

29.94

0.35

Total anthocyanins (mg/L) T1

418.74

416.70

-0.49

Total anthocyanins (mg/L) T2

280.34

266.08

-5.09

Observing a 10% difference between treatments as notable, only differences in hot climate wines were found. Results show cold soaking hot climate Cabernet dramatically increased colour density by 44.81% after nine months in bottle.

Cold soak reduced total anthocyanins in hot climate Merlot but colour density was increased. Cool climate Shiraz, Cabernet and Merlot showed little difference between treatments suggesting the influence of climate to be greater than variety when considering colour.

Contact information

Richard Fennessy
+61 (0)8 9780 6219

Author

Richard Fennessy