Influence of climate and variety on the effectiveness of cold maceration. Richard Fennessy Research officer

Transcription

1 Influence of climate and variety on the effectiveness of cold maceration Richard Fennessy Research officer

2 What is pre-fermentative cold maceration ( cold soak ) and what are the benefits? Introduction Crush destem Ferment Press MLF Mature Bottle Aqueous extraction This study aims to investigate if climate and variety influence the effectiveness of cold soak

3 Materials & method 24.9 C MJT (hot) 19.7 C MJT (cool)

4 Materials & method Vineyard and harvest specifications Variety Climate Vine age (years) Trellis Yield (t/ha) Baume ( Be) Shiraz Hot 12 VSP Cool 15 VSP Cabernet Hot 20 Sprawl Cool 25 VSP Merlot Hot 14 VSP Cool 15 VSP

5 Materials & method Small scale winemaking process 20 C, equal time on skins for both Be 30kg parcels 5 4 C

6 Analyses What was measured? Descriptive sensory analysis Colour (Modified Somers Assay) Qualitative volatile profiling Quantitative analysis of Rotundone (cool climate Shiraz only)

7 Descriptive sensory analysis Conducted on two occasions with a panel of winemakers Two replicates per treatment Wines completely randomised Grouped by variety and climatic region 0-9 numerical scale to rate intensity 2 months after bottling 9 months after bottling

8 Results Hot climate Shiraz 2 months post bottling 9 months post bottling Length** Colour depth Hue Length Colour depth Hue Flavour Herbacious Flavour Herbacious Sweetness Confectionery Sweetness Confectionery Astringency Red berry Astringency Red berry Texture Dark berry** Texture Dark berry Tannin** Dried fruits Tannin Dried fruits Weight Spice Weight Spice Leather Earthy Chocolate Leather Earthy Chocolate Red line control Blue line cold soak

9 Results Cool climate Shiraz 2 months post bottling 9 months post bottling Length Colour depth Hue Length Colour depth Hue Flavour Herbaceous Flavour Herbaceous Sweetness Confectionery Sweetness Confectionery Astringency Texture Red berry Astringency No significant differences Dark berry Texture Red berry Dark berry Tannin Dried fruits Tannin Dried fruits Weight Spice Weight Spice Leather Earthy Chocolate Leather Earthy Chocolate Red line control Blue line cold soak

10 Results Hot climate Cabernet 2 months post bottling 9 months post bottling Length** Colour depth** Hue** Length** Colour depth** Hue** Flavour Herbaceous Flavour** Herbaceous Sweetness** Confectionery Sweetness Confectionery Astringency Red berry Astringency Red berry Texture** Dark berry Texture** Dark berry** Tannin Dried fruits Tannin** Dried fruits Weight** Spice Weight** Spice Leather Earthy Chocolate** Leather Earthy Chocolate** Red line control Blue line cold soak

11 Results Cool climate Cabernet 2 months post bottling 9 months post bottling Length Colour depth Hue Length Colour depth Hue** Flavour Herbaceous Flavour Herbaceous Sweetness Confectionery Sweetness Confectionery Astringency Redberry Astringency Redberry Texture Dark berry Texture Dark berry Tannin Dried fruits Tannin Dried fruits Weight Spice Weight Spice Leather Earthy Chocolate Leather Earthy Chocolate Red line control Blue line cold soak

12 Results Hot climate Merlot 2 months post bottling 9 months post bottling Flavour Length Colour depth Hue** Herbaceous Flavour Length Colour depth Hue** Herbaceous Sweetness Confectionery Sweetness Confectionery Astringency Red berry Astringency Red berry Texture Dark berry Texture Dark berry Tannin Dried fruits Tannin Dried fruits Weight Spice Weight Spice Leather Earthy Chocolate Leather Earthy Chocolate Red line control Blue line cold soak

13 Results Cool climate Merlot 2 months post bottling 9 months post bottling Length Colour depth Hue Length Colour depth Hue Flavour** Herbaceous Flavour Herbaceous Sweetness Confectionery** Sweetness Confectionery Astringency Red berry** Astringency Red berry Texture** Dark berry Texture Dark berry Tannin Dried fruits Tannin Dried fruits Weight Spice Weight Spice Leather Earthy Chocolate Leather Earthy Chocolate Red line control Blue line cold soak

14 Colour Only observed differences in hot climate wines Post bottling 2 months 9 months Shiraz Ctrl CS % diff Ctrl CS % diff Colour density (a.u.) Total phenolics (a.u.) Total anthocyanins (mg/l) Cabernet Ctrl CS % diff Ctrl CS % diff Colour density (a.u.) Merlot Ctrl CS % diff Ctrl CS % diff Colour density (a.u.) Total anthocyanins (mg/l)

15 Qualitative analysis of volatile compounds Performed by gas chromatography / mass spectrometry (GC/MS) Non-targeted profiling based on metabolic profile specific to a range of 18 volatile fermentation derived compounds Range of compounds - ethyl esters, acetates and alcohols

16 Results Qualitative volatile profiling Hot climate Shiraz Cool climate Shiraz No significant differences

17 Results Qualitative volatile profiling Hot climate Cabernet Cool climate Cabernet Sweet/perfume Spiritous Banana/fruity Berry Sweet fruit Banana/fruity Nail polish

18 Results Qualitative volatile profiling Hot climate Merlot Cool climate Merlot Sweet/soapy Sweet/perfume Spiritous Banana/fruity No significant differences Berry Sweet fruit Banana/fruity Nail polish

19 Results Rotundone in cool climate Shiraz Analysis showed the control and cold soak wines contained 27 and 32 ng/l respectively (16ng/L threshold) Statistically no difference was observed between treatments Sensory panels did not find differences in spice attribute between treatments

20 Discussion Shiraz Hot climate Negative impact on colour No difference in volatile profile Initial negative impact on sensory No difference after a further 7mths Cool climate No difference in colour No difference in volatile profile No difference in sensory analysis Rotundone was not influenced

21 Discussion Cabernet Sauvignon Hot climate Positive impact on colour Differences in volatile profile Positive impact on sensory analysis Overall quality was improved Cool climate No difference in colour Differences in volatile profile Little difference in sensory analysis

22 Discussion Merlot Hot climate Impact on colour analysis Large differences in volatile profile Little difference in sensory analysis Cool climate No difference in colour No difference in volatile profile Initial differences in sensory analysis No difference after a further 7mths

23 Conclusion Cold soak is not a one size fits all technique Is influenced by climate and variety Winemakers should consider these variables when planning their maceration regimes

24 Acknowledgments DAFWA staff Andrew Taylor Glynn Ward Kristen Brodison Karyn Reeves Rebecca O Leary Funding

25 Thank you Visit agric.wa.gov.au