Fermentation

Grape juice is transformed into wine through the process of fermentation.  During primary fermentation, yeast cells feed on sugars in the grape juice and multiply producing carbon dioxide and alcohol.  Natural or wild yeasts are present on all grapes; however fermentation using these yeasts can give unpredictable results.  Winemakers  generally use sulfur dioxide to eliminate unwanted wild yeasts, molds and bacteria and innoculate with cultured yeasts.

In white wine production, only the grape juice itself is fermented and there is minimal contact with the grape skins and grapeseeds.  Chilled juice from the press is pumped into cooled stainless tanks (minus 2 degrees Celsius) for 'cold settling'.  Over a period of up to 3 days, the solids settle to the bottom of the tank after which the 'clear' juice is pumped to a new  stainless tank in perparation for fermentation.  The juice is blanketed with carbon dioxide while warming to 14-16 degrees Celsius.  The pH and TA (total titrable acidity) are adjusted and the juice is innoculated with yeast.  Fermentation takes place in stainless steel tanks fitted with temperature control mechanisms to maintain the temperature of the ferment  between 15-20 degrees Celsius.  The progress of the fermentation is monitored on a daily basis measuring the sugar content and the temperature.

Once fermentation has completed the wine is 'racked' or pumped off of the lees (dead yeast cells) into a clean stainless steel tank where the pH and TA is adjusted awaiting cold and heat stabilization.

In red wine production, the colour  is derived from the grape skins.  After destemming and crushing, the juice is pumped to stainless red fermenters or bins and left in contact with the skins throughout the fermentation.  The pH and TA (total titratable acidity) of the must are adjusted and the yeast  added.  The temperature is maintained at less than 30 degrees Celsius.

As fermentation proceeds the skins and pulp rise to the surface.  To prevent the 'cap' from drying out the skins are plunged 2-3 times per day.

The fermentation process is monitored daily measuring the temperature and sugar content.  Tannin additions are made as required.  Once the 'must' has reached approximately 1 Baume usually after 5 - 7 days, the must is pumped to the press.