Cold soak or pre-fermentation maceration. The wine is kept in an aqueous liquid at low temperature (10C) to avoid both fermentation and spoilage. The period can be between a few and as much as 20 days. The aim is to achieve less harshness and higher colour extraction, i.e: extraction of anthocyanins pre-alcohol from skins and stems.
To recap colour is obtained mostly during the first few days (anthocyanins) hence why cap management is critical. Battonage consists on pushing down the gross lees which float to the top of the tank/container to maximise colour and skin/stem extraction and it´s therefore critical for those first 5-7 days.
Cold soak gives a head start to achieving maximum extraction of phenolics including colour from skins and stems. Wine at this point would reach its maximum colour, from here on anthocyanins and tannins react (polymerise) and form polymers. In colour terms, the wine moves from its strongest point of red/blue/black towards the brown/orange that comes with wine aging.