WINE MAKING

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WINE MAKING:

WINE MAKING BY, Stephy Maria Sebastian S 4 FST MACFAST

Wine :

Wine Wine is a drink made by the partial or complete fermentation of the juice of fresh grapes. And it is a natural process. Grapes are the only fruit with a high level of sugar and with the proper balance of acid and nutrients to sustain a natural fermentation to dryness with stable results.

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Other fruits or berries may be fermented, but without additions of sugar, acid or various yeast nutrients, they may readily spoil. Fermentation is a spontaneous act of nature and it is a set of basic process by man. Grapes were crushed to release the juice (must) int a fermentation vessel. When fermentation was complete, the wine was pressed by mechanical means to separate the the liquid from stems, skins,pips and pulp. It was then stored to age and clarify until it was drunk.

Fermentation :

Fermentation It is a natural process. Grape would ripen until the skin broke and the juice fermented. Intervention of man is only necessary to increase the clarity and stability of the end product. Yeast ( sacchromyces cerevisiea ) helps in fermentation process.

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They comes in contact with the grape juice, it begins to feed on it grow and reproduce. There are approximately 6000 yeast cells per ounce of actively fermenting must by budding. An enzyme zymase within the yeast converts sugar in the grape juice into alcohol and Co 2 and also release energy in the form of heat. When the alcohol level reaches 14% to 15% the fermentation process will be stop.

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Unfermented must contains perphaps 24% sugar together with malic acid, tartaric acid, cream of tartar, protein,tanin and colouring matter. After fermentation the fermented must contains typically 11% alcohol and .2% sugar together with co 2 , malic acid, cream of tartar, protein, tannin, colouring matter and glycerol. The acohol formed in wine production is ethyl alcohol or ethanol.

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Fermentation may takes from a week to a month depending on temperature and climatic conditions. The average time is 2 weeks. Traditionally must is put into fermenting vats made of wood but nowadays corrosion resistant stainless steel vats are used.

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White wines are fermented in a closed container at a temperature 45 F – 65 F and this a slow fermentation. Red winefermentation takes place in an open container and its temp range is 70 – 90 F. “ cuvaison ” is fermentation process for red wine which gives color by extractacting grapes skin.

Racking :

Racking Means filtering or fining. Transfer of wine from one container to another by using gravity rather than a pump and leaving the lees (impurities) behind. Wine is racked into fresh casks several times to remove the lees to obtain a clear bright wine.  A racking tube is used and can be attached to a racking cane to make the task easier. The racking process is repeated several times during the  aging of wine .

fining:

fining Fining consists of “adding wine to a clarifying agent capable of coagulating and forming flakes , which settle causing particles to precipitate thus having a clarifying effect” Finings used are; Egg albumin   isinglass  obtained from the  bladders of fish .  Egg white They combines with part of wine and forms an insoluble tannate film, they slowly precipitate and acting as a filter.

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4. Bentonite , a collodial clay helps to precipitate unstable albumin. Too much albumen takes the colour out of red wine. In a process known as  blue fining ,  potassium ferrocyanide  is sometimes used to remove any  copper zinc and  iron  particles that have entered the wine from bentonite . After a few hrs fining settels as a bluish sludge which is removed by filtaration or racking.

Filtration :

Filtration The key role of filtration in wine-making is to provide stabilization It can remove more suspended solids than several rackings . Usually asbestos sheet filters are used which are available in various grades. filtration works by passing the wine through a filter medium that captures particles larger than the medium's holes. Which are capable of removing the bacteria and sterilizing the wine.

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Most filtration in a winery can be classified as either the coarser  depth filtration  or the finer  surface filtration In depth filtration, often done after fermentation, the wine is pushed through a thick layer of pads made from  cellulose  fibers,  diatomaceous earth   or perlite . The finest surface filtration,  microfiltration , can sterilize the wine by trapping all yeast and, optionally, bacteria, and so is often done immediately prior to bottling. 

Maturing :

Maturing After fermentation wine is exposed to air,due to oxidation of wine, will turn acetic acid or vinegar. It is stored in casks, bottles or other vessels filled and leaving little air space. However the wooden casks and bottle corks allow a small amt of o 2 to pass through make biochemical changes that donot destory the wine but mature it improving the flavour and texture.

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The quality of red wines will improved by aging. The better the quality of wines, the longer it takes to mature. White wine donot need to be matured as long as red wines. During maturation the color of red wine will changes to purplish bluish to garnet shade and white wines to golden colour .

Blending :

Blending Most vintage wines are not blended. They are usually the individual wines from vineyards. But some vintage wines such as port, champagne etc..are wines of 1 year, And they produced by many wineyards blended together. And a standard acceptable wine is developed with right amt of acidity, tannin content etc.

Bottling :

Bottling Bottling depends on type of wine. Bottles are sterlized with sulphur dioxide and corks are washed in warm water. Then wine filled into bottles, after corking the corks are wiped carefully to remove any dirt. And cork is protected by covering with metal foil or by dipping in sealing wax. Originally lead alloy was used for foil, but nowadays aluminium is used. The cork used are made of oak, fire board oak, plastic etc…

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Thank you