Wine making

The processes involved in wine making including

•red, white and rosé•fermentation•fortified

Wine making

• 4 stages:

• Pressing

• Fermentation

• Casking

• Bottling

Stage 1: Pressing

• Grapes ferment naturally because they contain glucose, fructose ,water and yeast

• The yeast is naturally present on the skins of the grapes (bloom)

• The bloom contains a mixture of wine yeasts and wild yeasts

• Juice is extracted from grapes by crushing them in a press and sulphites are added to destroy undesirable wild yeasts

Stage 2: Fermentation

• Glucose and fructose are converted to alcohol.

• If fermentation continues until all the available sugar is used up, the resulting wine is dry.

• If some sugars remain , it is sweet.• Yeasts cease fermenting when the alcohol

content exceeds 15- 16%.• Sometimes benzoates are added to stop further

fermentation

Stage 3: Casking

• After fermentation the wine is racked to separate the wine from the sediment

• Wine is transferred to wooden casks or stainless steel containers.

• Some wines remain in the cask for many years whilst secondary fermentation takes place.

• A few live yeast cells remain from the fermentation stage.

• The wine slowly matures in the cask

Stage 4: Bottling

• Wine once bottled , continues to mature. The longer the maturity , the richer the flavour and the more expensive the wine.

Classification of wine

Red Rosé White

Red wine• Produced from black grapes, which are pulped

and fermented along with the skins.• The blue/black pigments of the anthocyanins

turn red in the presence of the acids in the grape juice

• The longer the skins remain in the fermentation, the darker the colour.

Rosé wine

• Rosé wines are produced in a similar way to red, but the skins only remain for about 24 hours before straining

White wines

• These can be made from most grapes, even black ones.

• The wine is only made from the grape juice, not the skins.

• “White wines” often have a yellow tinge and may even be brown ( if it has been aged in a wood barrel)

Quality and characteristics of wine

• Variety of grape- produce different colours and flavours

• Climate-sufficient rainfall and warmth is needed for grapes to ripen

• Soil- water holding capacity, drainage, nutrients• Method of manufacture- modern v traditional• Maturation- in bottle or cask. Flavour

compounds develop over time

Flavour of wine

• Acids from the grape juice

• Tannins from the skins, stalks and wood of the barrel

• Small amounts of esters are formed - a reaction between the acid and alcohol. These give a fragrant, floral aroma

Fortified wines

• Wines such as port ,sherry ,Madeira and Marsala are said to be fortified

• These have an alcohol content of 17-21%. To achieve this, spirit, usually brandy of lower quality is added to fortify a normal wine.

• The advantage is that these keep well because the alcohol content is sufficiently high to kill micro organisms

What happens to alcohol in the body?

Alcohol is absorbed from the stomach and the small

intestine. This occurs more slowly if alcohol is drunk

with food. It is soluble in water and carried around the

body in the bloodstream.

Alcohol is removed from the blood by the liver over a

period of several hours. The rate at which this happens

depends on age, sex, body weight, liver size and how

much alcohol was consumed.

How does alcohol affect the body?

As the level of alcohol in the bloodstream increases it has an affect on a person’s behaviour.

Short term:Reaction times are slower.Increased risk taking.Judgement becomes blurred.Co-ordination is poor. This is why it is dangerous to drink alcohol before driving a car.

Long term:Can lead to liver damage such as cirrhosis and livercancer and the vitamin B deficiency disease beri-beri.