wine=roll no 51
TRANSCRIPT
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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.