Cold, soak, whole cluster and stem additions in Pinot noir

by | Feb 19, 2019 | South Africa Wine Scan

The aim of the study was to investigate the chemical and sensory effects of cold soaking and the addition of whole clusters and stems to Pinot noir musts.

Project layout:

  • Own rooted Pinot noir grapes from Mendoza were harvested in two consecutive vintages, 2014 and 2015, at 22.8°Brix and 25.2°Brix respectively. The 2014 vintage was much cooler than the 2015 vintage.
  • In 2014 the experimental design consisted of four treatments: control (C), control + 20% whole clusters (C + WC), cold soak (CS) and cold soak + 20% whole clusters (CS + WC).
  • In 2015 two extra treatments were added namely: 3% stems were added to control (C + S) and cold soak wines (CS + S), making it six treatments in total for 2015.
  • Cold soaking was done for five days at 6.7°C on average.
  • Control wines and controls plus either WC or S were all macerated for 10 days in total at 25.5°C on average.
  • Cold soak wines, with and without additions, were macerated for 15 days in total.
  • Wines were all fermented with EC 1118 and MLF was conducted with VP41 (inoculation 48 hours after the onset of fermentation).
  • Whole berries from WC wines were recovered after fermentation and not pressed and added to the free run wines.
  • Wines were stabilised, bottled and analysed chemically and sensorially (descriptive analysis).

Main results:

  • The basic chemistry of the wines were not affected by the different treatments.
  • Addition of 20% whole clusters did not affect anthocyanin and tannin content. It is possible that 20% addition is too low and that higher concentrations of whole cluster addition may lead to higher tannin content.
  • In the 2015 wines the stem additions did increase tannin content.
  • In 2014 cold soaking increased tannin extraction (37%) from the unripe fruit, but had no effect on the 2015 ripe fruit.
  • Cold soaking on its own had no effect on colour saturation in the 2014 vintage but decreased colour in the 2015 vintage. When combined with other treatments (WC or S) cold soaking did not decrease colour.
  • In 2015 stem addition increased both colour and tannin.
  • Control wines were fruitier (higher beta-demascenone concentrations) and less astringent and bitter than treated wines. They were also less aromatically diverse.
  • 2014 cold soak wines had higher astringency but no increase on astringency was found for 2015 cold soak wines, most probably since tannin extraction did not increase.
  • Additions of whole clusters reduced fruitiness but enhance floral (2014 and 2015) and bitter almond aromas (only 2014).

Significance of the study:
In this study cold soaking overall had very little effect on the Pinot noir sensory properties. Whole cluster additions and stem additions produced wines with distinctive sensory properties. The effects (positive or negative) of these treatments were greatly affected by vintage variation.


Image: Wikimedia

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