As we know, during making of a red wine, the grapes picked from the vines are crushed to form a ‘Must’. This is followed by addition of Yeast to make wine by the process called as Fermentation. Often winemakers add a pre-fermantation stage too by means of a “Cold Soak”. Pioneered by the famed innovator Henri Jayer, in this technique winemakers delay the fermentation by a few days by lowering the temperature of the Must to around 5 – 10°C. This is done by adding dry ice in fermentation barrels/tanks.
It is thought that while grape skins are in contact with juice prior to fermentation and alcohol formation, overall extraction of aroma and flavour compounds is enhanced due to slow, soft extraction of colour and flavours from red grape skins. This is considered to improve the overall quality of the wine produced.