Wine Production : Vine to Bottle - Vinum Vine

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labour is cheap, the cost of staffing a selection table can easily be
justified, but in France, for example, many producers of inexpensive
wines simply cannot afford such a ‘luxury’.
16.4.3 Problems with crushing, destemming or
pressing
If the crusher–destemmer or press is old, out of adjustment or not
operated carefully, several problems can ensue. For example, it is
important that if a destemmer is used the equipment should remove
and eject the entire stems. Poor equipment may break up the stems,
giving a wine which is very stalky and harsh as a result of the presence
of stem tannins. If the rollers of the crusher are out of adjustment,
the pressure may be too great, crushing the grape pips and releasing
bitter oils into the must.
CHAPTER 16
16.4.4 Lack of control of fermentations
It is important that the temperature is controlled throughout the
fermentation period. Winemakers dread a fermentation ‘sticking’ –
stopping before all the sugar has fermented out. This can happen
for several reasons: the temperature may have exceeded that at which
yeasts will work (approximately 35° to 38 °C), or the juice may be
deficient in oxygen or nutrients.
16.4.5 Delays in post-fermentation racking
If, due to delays in racking, the lees start to decompose, then off
flavours will be imparted to the wine.
16.4.6 Lack of attention to barrels
Barrels must be clean and sterilised. Sulphur is the traditional means
of sterilisation. The belief that wines must be topped up regularly
during the first year of maturation is now challenged, but all would
accept that oxidation is the great enemy. Fig. 16.1 shows topping
up taking place at Château d’Yquem.