Wednesday, 14 December 2011
Wine is the product of grapes which can be obtained after alcoholic fermentation by yeast. Technically it is the transformation of sugars of grapes by yeast under anaerobic conditions into carbon dioxide, ethanol and some by products. Wine can also be produced by the fermentation of the fruit juices, honey and berries.
a) Wine from Grapes: Basically two types of grapes: Red and white ones are used for production of 2 different types of wines; namely RED WINE AND WHITE WINE. Grapes with a sugar content of 15- 20% are appropriate for extraction after harvesting. Whole process involves stemming, cleaning, crushing followed by addition of sodium or potassium meta-bisulphite to check the growth of undesirable organisms. Crushed grapes so obtained are known as MUST.
b)Fermentation: Fermentation is carried out by adding 2-5% of wine yeast namely: Saccharomyces crevisiae in the MUST. The contents should be mixed twice a day by punching the cap of floating grapes so as to allow the profuse growth of yeast due to increase in aeration. This step helps in extraction of colour. Thereafter mixing should be stopped and anaerobic fermentation is carried out by maintaining temperature at 24-270C for about 3-6days (in case of red wine) and around 10 – 200C for about 4-12 days (in case of white wine).
c)Recovery: Once the fermentation is completed the fermented juice is drawn off and stored under the atmosphere of CO2 for further fermentation for about 7 – 12 days temperature of 21-290C.
Thereafter wine is pasteurized before aging. During pasteurization the protein is precipitated and removed. After filtering the wine is transferred in the wooden tanks. It is believed that aging is important for imparting flavour, aroma, sanctity and colour to the wine. After aging wine is ready to clarify and then it is bottled.