The major white wine varieties produced at Jane Brook are Chardonnay, Chenin Blanc, Verdelho and Sauvignon Blanc.  White wines require very careful handling from the juice, through to the finished product to avoid oxidation (browning), hence the addition of the anti- oxidants, sulphur dioxide (220/223) and ascorbic acid (300). 

The grapes are crushed in a destemmer-crusher which functions to break the skins to liberate the juice and discards the stalks.  The "must" (crushed grapes and juice) is pumped via the must pump into a refrigerated stainless steel draining tank from which the "free run" juice is drained off via an internal screen and pumped into a refrigerated stainless steel tank.  

 

The remaining must in the drainer is then "pressed", here the balance of the juice is extracted and added to the free run.  This juice is cloudy due to the suspended particles of grape flesh being held in suspension by pectins (important for keeping cells in a structured position).  Thus pectin splitting enzymes are added both at the crusher and to the juice to quicken the process of juice settling and clarification.  

 

From juice separation the juice is allowed to settle at 1-2 degrees Celsius for two to four days before being racked (pumping the clear liquid from the settled sediment) and/or filtered, before being inoculated with a selected freeze dried specially selected yeast strain - Saccharomyces cerevisiae or Saccharomyces bayanus.  Yeasts used at Jane Brook are constantly under review to ensure that the style of wines produced truly reflect varietal characters.

Fermentation takes place in refrigerated stainless tanks at temperatures between 11 degrees and 15 degrees Celsius, over a period of 4 - 8 weeks.  Daily baume` and temperatures are taken to carefully monitor the rate and temperature of the fermentation.

At the completion of fermentation, when all the grape sugars have been converted into ethanol by the yeasts, the wine is chilled down and allowed to settle before being racked off primary/gross lees.  The wines are regularly tasted and analysed to allow accurate adjustment and measurement of sulphur dioxide, ph and titratable acidity.  Laboratory trials are used to determine the minimum additions required.

Prior to bottling, the wine must be both cold and protein (heat) stable to avoid potential instability in the bottle.  Cold stabilising involves freezing the wine to approximately -2 degrees Celsius for two to three weeks to ensure the precipitation of potassium bitartrate crystals.

Protein stability is effected by the addition of bentonite, a siliceous clay which removes heat and cold unstable protein.  If a wine is not protein stable there is the possibility of the wine becoming cloudy in normal or warm conditions.

The different wine styles influence how the wine is made.  Chardonnay is both fermented and matured in French oak barrels, in contrast to Sauvignon Blanc which is fermented in stainless steel at 12 degrees Celsius.  Hence Chardonnay has the complexity and flavour of oak ageing, whereas Sauvignon Blanc has the fresh fruit characters of the grape dominant in the bouquet and palate.

 

To view a diagram of the white winemaking process click here