White Grape Wine

Location of production - White grape wines are made in many African, Asian and Latin American countries including Algeria, Morocco and South Africa.

Product description - White grape wine is an alcoholic fruit drink of between 10 and 14% alcoholic strength. It is prepared from the fruit of the grape plant (Vitis vinifera), and is pale yellow in color. There are many varieties used including Airen, Chardonnay, Palomino, Sauvignon Blanc and Ugni Blanc (Ranken, Kill and Baker, 1997). The main difference between red and white wines is the early removal of grape skins in white wine production. The distinctive flavour of grape wine originates from the grapes as raw material and subsequent processing operations. The grapes contribute trace elements of many volatile substances (mainly terpenes) which give the final product the distinctive fruity character.

  • Selection of grapes
  • Mature and undamaged grapes
  • Crushing
  • Traditionally manual but now usually by crushers
  • Removal of skins
  •  
  • Clarification
  • By standing, filtration or centrifugation
  • Fermentation
  •  
  • Ageing
  •  

    Preparation of raw materials - Ripe and undamaged grapes should be used. The grapes are crushed to yield the juice and the skins are removed and separated out. Sometimes the juice is clarified by allowing it to stand for 24 to 48 hours at 5 to 10 C, by filtering or centrifugation. Pectolytic enzymes may be added to accelerate the breakdown of cell wall tissue and to improve the clarity of juice. Excessive clarification removes many of the natural yeasts and flora. This is beneficial if a tightly controlled induced fermentation is desired, but less so if the fermentation is a natural one. Long periods of settling out however, encourage the growth of natural flora, which can contribute to the fermentation.

    Processing - The clarified juice is transferred to a fermentation tank where fermentation either begins spontaneously or is induced by the addition of a starter culture. Traditionally, fermentation was carried out in large wooden barrels or concrete tanks. Modern wineries now use stainless steel tanks as these are more hygienic and provide better temperature control. White wines are fermented at 10 to 18 C for about seven to fourteen days. The low temperature and slow fermentation favours the retention of volatile compounds (Fleet, 1998).

    The fermentation can be from naturally occurring yeasts on the skin of the grape or using a starter culture of Saccharomyces cerevisiae. This approach produces a wine of generally expected taste and quality. If the fermentation is allowed to proceed naturally, utilising the yeasts present on the surface of the fruits, the end result is less controllable, but produces wines having a range of flavour characteristics. It is likely that natural fermentations are practised widely around the world, especially for home production of wine.

    During storage, wines are prone to non-desirable microbial changes. Yeasts, lactic acid bacteria, acetic acid bacteria and fungi can all spoil or taint wines after the fermentation process is completed.

    Packaging and storage

    Traditionally wine was delivered to the point of sale in casks. The product is traditionally packaged in glass bottles with corks, made from the bark of the cork oak (Quercus suber). The bottles should be kept out of direct sunlight. During storage, wines are prone to non-desirable microbial changes. Yeasts, lactic acid bacteria, acetic acid bacteria and fungi can all spoil or taint wines after the fermentation process is completed.

    Caution - Homemade coffees, wines and liqueurs do not have the shelf life of commercial brands! In many instances the use of extracts is preffered instead of cooking and breaking down fruits - to expedite the ageing process and prevent acidity or fruit sedimentation (this also sometimes prevents the natural flavours to permeate the liqueur)! Sugars, coffee, chocolates, and fruits added with water can introduce contaminants to liqueurs so refrigerate upon opening, serve and enjoy as soon as possible!

     

    Return to the Main Index to Elkin Vanaeons Website fro the Mysts of Time
     


    Idaho Web Design Tools
     Idaho Web Design Tools