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WinePRESENTED BY:- SUMNEET KAUR

ROLL NO:-51

B.TECH (HONS)BIOTECH

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Wine production

Wine is fine

Produced from the fermentation of

fruit juice, usually from grapes

Wine production started in ancient

times, probably when the natural

yeasts accidentally contaminated grapejuice

Pasteur also discovered the

microbes responsible for wine spoilage

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Fermentative organisms

Starters are not always added but

sometimes S. cerevisiae or S. bayanus

are to give a more consistent product

Native grape yeasts are mostly

Kloeckera and Hansenia spp.

(Candida, Pichia, and Hansenula spp.

are also found

All of these yeasts are present inlow numbers on immature fruit, but

increase exponentially as the grapes

ripen

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FermentationThe must undergoes primary fermentation

Natural yeasts on the skins of the grapesmay be used, but in commercialproduction cultured yeast is often used to

give more predictable resultsThe amount of sugar in the must duringfermentation is measured with asaccharometer (a calibrated hydrometer)

Malolactic fermentation by bacteria inthe must converts malic acid into lacticacid

After primary fermentation, the must ispressed (red wines) and transferred todifferent containers for secondaryfermentation

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FermentationSecondary fermentation and

aging

Takes 3 6 months

Done in either stainless steelvessels or in oaken barrels

The vessel is kept airtight to

prevent oxidation

Proteins are broken down, &

particles settle

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Wine flavour depend upon

sugar-to-acid ratio

climate

soil

vine age

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Types of wine

White wines

Red wines

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White wines

The juice is drained awayfrom the skins immediatelyafter crushing

The juice is then clarifiedand sent to the fermentation

White wine fermentation isusually complete in 1 2

weeks at 10 18o C

The low temperature helpsretain important volatileflavors

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Red winesAfter fermentation has

started, the liquid is

pressed through the skins

into a fermentation tankFermentation usually

lasts about 7 days at 20

30o C to extract the red

colorFermentation ends

when glucose and

fructose are completely

utilized

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Products ofFermentationEthanol and CO2 are the

main products of fermentation

Glycerol is sometimes

produced and it can smoothen

the taste and impart viscosity

Higher-alcohol esters and

aldehydes can be produced asflavor compounds

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Post-fermentationRed wines are stored in oak

barrels for 1 2 years for flavor

development

Barrels may be made with

smoked woods, resins, or other

flavor-induced mechanisms

White wines are usually notaged

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Post-fermentation

Potassium sorbate

can be added to red

or white wine tocontrol yeast

spoilage

Wine is then

filtered to clarity and

bottled

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Thanks.