WINE PRODUCTION INTRODUCTION - PowerPoint Presentation

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WINE PRODUCTION

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INTRODUCTION

Winemaking, or vinification, is the production of wine.Although most wine is made from grapes.Mead is a wine that is made with honey being the primary ingredient after water.

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Wine

Production

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Red & White Wine Production

One of the first things they realized was that 

red wine production

 required that the grapes be fermented in contact with their skins. This gives the wine color and body. In contrast, most 

white wine production

does not occur in contact with the grape skins. Whites are valued for their fresh fruit characteristics, and skin contact would impart unwanted bitter tannins.

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Wine Production : Main

Steps

Viticulture

Harvesting

Stemming/Crushing

Fermentation

Draining

Pressing

Mixing

Clarification

Aging

Bottleing

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Wine Production: Process

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Wine Production

Factors which

inflence

grape’s flavor:

climate of the vineyard’s region

drainage around the vines

humidity of the region

sun exposure.

soil quality

1.

Viticulture

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Wine Production

2. Harvesting

Grappes are

picked

up by hand or mechanically

Descision of harvest informed by level of sugar and acid

weather forecasts

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Wine Production

3. Stemming/Crushing

Stemming

is the separation of the stems and grapes (which are sends to the press)

Crushing:

A horizontal press squeezes the broken grapes, separating the fresh juice (must) from the skins (marc)

After crushing starts the fermentation process.

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Wine Production

4. Fermentation

sugar and acids that naturally react with wild yeasts

Vineyard adding their own yeasts

fermentation can take from 10 to 30 days to convert natural sugar to alcohol.

5. Draining

Liquid wine is drained from the vat without being pressed and go into barrels (

free-run wine

). The remaining pulp retains about 20% of the wine.

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Wine Production

6. Pressing

The remaing pulp, after draining, is pressed to squeeze out the

press wine

. The press wine tends to be dark, harsh and unpalatable, and is mixed with free-run wine to produce something decent.

7. Mixing

The free-run wine and press wine, always from the same source, are mixed together in appropriate ratios to obtain the desired balance.

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Wine Production

8. Clarification

Clarification is the step of stabilisation of fermentation.

During clarification all remaining solids are removed from the fermented liquid.

Clarification done in numerous ways:

fining, a process that calls for the addition of substances that cause the solids in the liquid to adhere to one another and sink to the bottom of the vat

running the liquid through coarse and fine filters

siphoning the liquid off the top of the fermenting vats after the solids have settled to the bottom

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Wine Production

9. Aging

The final stage in vinification is aging the wine. At this point, the clarified wine is transferred into either wooden barrels or metal vats in which the wine is allowed to further mature and develop flavors. If a winemaker chooses to age the wine in wooden casks, he will be allowing the wine to pick up flavors from the wood, adding greater depth to its flavors. While this can add body to some wines, keep in mind that the “woody” flavor isn’t suited to all types of wine, hence the use of metal vats.

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Wine Production

10.

Bottling

The

final step of wine production.

A dose of sulfite is added to help preserve the wine and prevent unwanted fermentation in the bottle.

The wine bottles then are traditionally sealed with a cork, although alternative wine clossure such as synthetic corks and screwcaps, which are less subject to cork taint, are becoming increasingly popular.

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Crushing and primary (alcoholic) fermentation

Crushing is the process when gently squeezing the berries and breaking the skins to start to liberate the contents of the berries.

the harvested grapes are sometimes crushed by trampling them barefoot or by the use of inexpensive small scale crushers.larger wineries, a mechanical crusher/destemmer is used.

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Secondary (malolactic) fermentation and bulk aging

During the secondary fermentation and aging process, which takes three to six months, the fermentation continues very slowly.

The wine is kept under an airlock to protect the wine from oxidation.Proteins from the grape are broken down and the remaining yeast cells and other fine particles from the grapes are allowed to settle.The secondary fermentation usually takes place in either large stainless steel vessels with a volume of several cubic meters, or oak barrels, depending on the goals of the winemakers.

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Malolactic fermentation

Malolactic fermentation occurs when lactic acid bacteria metabolize malic acid and produce lactic acid and carbon dioxide.

Malolactic fermentation can improve the taste of wine that has high levels of malic acid, because malic acid, in higher concentration.White wines vary in the use of malolactic fermentation during their making.

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Preservatives

The most common preservative used in winemaking is sulfur dioxide.It added in one of the following forms: liquid sulfur dioxide, sodium or potassium metabisulphite. Another useful Sulfur dioxide has two primary actions, firstly it is an anti microbial agent and secondly an anti oxidant. In the making of white wine it can be added prior to fermentation and immediately after alcoholic fermentation is complete.

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If added after alcoholic ferment it will have the effect of preventing or stopping malolactic fermentation, bacterial spoilage and help protect against the damaging effects of

oxygen.preservative

is potassium sorbate.

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Bottling

A final dose of sulfite is added to help preserve the wine and prevent unwanted fermentation in the bott

Then filled in the bottel.

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21

spirits

The word distillation comes (from the

Latin

destillare

meaning to drip) which is the extraction of higher alcohols from fermented drinks by using the action of heat to

vapourize

them. Basically what distillation is the

concentration or increasing of alcohol strength

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A 

distilled beverage, spirit, or liquor is an alcoholic

beverage  containing ethanol  that is produced by distilling  (i.e., concentrating by distillation

) ethanol produced by means of fermenting  grain, fruit, or vegetables. This excludes undistilled fermented beverages such as beer, wine, and cider

.

 Vodka, 

gin,

rakı,

 baijiu, tequila, rum, whisky, brandy,

Singani

 and 

soju

are examples of distilled beveragesDefinition

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The term 

spirit refers to a distilled beverage that contains no added sugar and has at least 20% alcohol by volume (ABV).

Beer and wine, which are not distilled beverages, are limited to a maximum alcohol content of about 20% ABV, as most yeasts cannot reproduce when the concentration of alcohol is above this level; as a consequence, 

fermentation ceases at that point.Hard liquor is used in North America and India to distinguish distilled beverages from undistilled ones

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Raw materials of Distilled Spirits

The availability of this base ingredient and the uniqueness of the land which is it grown all play an integral part in the different complexities and qualities found in these distilled spirits.

Anything that can be fermented can be used as a raw material for spirits – whether fruit, grain or vegetable. Where sugar is present in the primary material, as in molasses or fruit, the fermentation can be started directly.

Some spirits can be made from one particular material only, (i.e. whiskey, vodka, genever), some schnapps and akvavit from grain. Other, such as Vodka, can be made from a broad range of raw materials, including various grains, potatoes, and even sugar cane and grapes

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Methods

of Alcohol Separation

Two distinctively different methods to separate alcohol: Congelation method (freeze distillation) and the boiling method or (heat distillation)

which is commonly referred to as the distillation method. Congelation (cold extraction): separation by freezing below zero degrees Celsius or 31F degrees;

only problem with this method is that this is a dangerous method of separation,

most International countries do not officially recognize this method of alcohol separation and have banned its use making the method of alcohol separation illegal,

less than 2% of the worlds distilled spirits are made using this method.

Distillation (heat extraction):

separation by

vaporization

of the fermentable liquid at

78.5

degrees Celsius or 172

Degrees Fahrenheit to create alcohol’. scientifically the best separation method and research figures indicate that this method accounts for 98% of the worlds spirits produced, the most widely method officially recognized by International governments to separate alcohol for creating spirits which taxes and duties are levied.

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Distillation

Water – boils at 100 C (212 F)

Ethanol – boils at 78.5 C (173.3 F)

Mixture is heated; ethanol gas is driven off at lower temperature; gathered in condenser – note, various devices added to minimize water vapor from escaping

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Distilled Alcoholic Beverages - Whiskeys

Whiskey: made from malted barley, or malted barley + other grain

proof = twice concentration of alcohol (90 proof = 45% alcohol)

Scotch: made from barley malt; aged in charred casks

Bourbon: from Bourbon Co., Kentucky – 51+% corn

Tennessee sour mash: similar to bourbon; filtered through charcoal

Rye: 51% rye grain

Straight whiskey: <80 proof; aged 2+ years in new charred barrels

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Principles of Distillation

Pot Still: (alembic or alambic)

This looks like a large copper kettle and is heated by direct heat. The vapours collect in the head and are led off through a narrow tube at the top, called the swan’s neck from where they go to the condenser. Here they are liquefied. Such a still is not very heat-efficient, but it produces spirits with character

.

Pot still distillation is a

small batch process,

This redistilling often several times is necessary to achieve the appropriate alcohol level.

Most spirits made with a pot still are double distilled, but sometimes it is done in three or even four stages (i.e. Irish whiskey, distilled three times).

Several spirits are produced using the Pot still: Cognac, brandy, Scotch malt whisky, Irish whiskey, American Bourbon whiskey, some rums (usually the darker ones) and some other spirits.

Pot Still: (alembic or

alambic

)

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Principles

of Distillation

The Still man: separates the poisonous parts (methanol, propandl, butanol), from the required spirit (ethanol). The still

man identifies all these separations and parts by (a) tell by nose and (b) the rising hydrometer, the first and the last parts will not be included in the final spirit as they contain toxic compounds.

Continuous still:

(referred to as the Patent, Column or Coffey Still):

invented by Robert Stein in 1820, developed by

Aeneas

Coffey.C

onsists

of two tall columns, each about sixty feet in height, called the analyzer and the rectifier.

The

alcoholic wash is broken down into its constituent vapours, or analysed, in the analyzer, and the vapours are selectively condensed, or rectified, in the rectifier. Large coffey still (exterior view).Coffey still diagram. Small coffey still (interior view)

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Maturing

and Oxidation

The barrel: most common vessel used for maturing spirits, usually 500-litre size (although smaller sizes can also be used

which restricts the oxygen intake and changes the character of the final spirit) wooden barrel help the chemical reactions, extraction of taste, extraction of bouquet and extraction of colour.

Evaporation

loss of spirit (like

angels share

contains dangerous fusel oils this

vaporises

first.

In summary the wooden barrel helps the spirit to;

change as the

congeners (fusels) interact with air filtering through the porous wooden barrels new congeners are absorbed from the wood itself, adding flavouring agents to the final spirit (flavours are married, blended). Not all spirits are aged. Wood finishes: More and more, some distilleries are producing whisky with various finishes, achieved by the last 6 months to 2 years of maturationbeing in ex-Sherry, ex-Port, ex-Madeira, Maturation periods: can differ (a minimum of 3 years before it can be legally called Irish or Scotch whiskey).

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Used Bourbon cask

American white oak.

French oak cask

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Brandies are distilled wines.

The most famous come from France. Cognac is one type.The fermented juices of many other fruits are also distilled.Liquers differ from brandy in that various flavoring agents are added. They have sugar and syrups added.

Brandies

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By the 15th century, the English and Scots had begun distilling barley beer and, in the 16th century, cognac was prepared in France. Whiskeys were made in a similar way.

Once distilled, the mixture is diluted back to about 50% alcohol in general. Whiskeys are aged in (usually oak) barrels.

The inside of these barrels is often charred. The barrel provides some of the flavoring materials.

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Scotch whiskeys have a characteristic taste because of the smoking process (over peat) used to dry the malt.

Bourbon whiskey is made from corn as the primary grain (

Zea mays, Poaceae) and was developed by the early Scottish (many of whom are called Scots-Irish) immigrants in Pennsylvania.These whiskies are aged for at least two years in new, charred oak barrels.

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Aging of whiskey in charred white oak barrels

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Other distilled beverages

Gin and vodka are distilled to a high percentage of alcohol and in the case of gin,

Juniperus communis, Cupressaceae, "berries" are added.These beverages can be distilled from almost any fermented mixture including potatoes, grains, etc.

Rum is made from fermented molasses or sugar cane juice.

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Tequila and mescal

Tequila and mescal are distilled from

pulque made from various Agave species.

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38

Fig:-Distillation process

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USES:

Used as beverage

Burn it - as fossil fuels

Wear it - in perfumes

Wash with it – for cleaning

Dissolve in it - extracts

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Production

of Rum

2

kinds

of

Rum

:

The

industrial

: the

alcohol

resulting

from

distillery

of molasses

The agricultural

:

alcohol obtained by distilling the fresh, fermented cane juice

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PRODUCTION LINE

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reaped

during the drying period

cut into short logs and bundled for transport crushed as soon as possible to avoid drying and deterioration of the sugar

THE CANE CUTTING

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weighed, controlled and discharged.

millings stages: to separate the cane juice (vesou) from the fibbers (the

bagasse)The bagasse serves as combustion for the furnaces

The

vesou

is gathered in a drainage

system for filtering and pumped on

to the fermenting vats

CRUSHING

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Process

of transforming the sugars into alcohol :

optimal temperature 30 C°yeast (private of oxygen) 72 hours after…Cane wine is obtained:

moût (7% of alcohol)Moût is quickly sent for distillation

THE FERMENTATION

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THE DISTILLATION

Definition

: The method consist in heating the wine to vaporize the volatile components, mainly the alcohol, and then to condense them

The column give to the Rhum its own characteristics.

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THE AGEING

White Agricultural Rhum

:

stored in huge wooden tuns to be "rounded out“ (before bottling)

Spring water is crossed to have the degrees desired for commercialisation (40° to 62°)

Golden agricultural Rhum or amber agricultural Rhum :

stored for at least 12 months in wooden containers.

golden colour: due to its short period spent in an oak tun

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Other

distilleted beverages

Rakı

 is an

unsweetened

, 

anise-flavored

Turkish

alcoholic

 

drink

 that

is

produced

by

grape

.

is an unsweetened, anise-flavored Turkish alcoholic 

drin

k.

Brandy

 

is

a spirit produced by 

distilling

wine

. Brandy generally contains 35–60% alcohol by

volum

e.

Gin

 is a spirit which derives its predominant

flavour

from juniper

berries

(

Juniperus

communis

)

Vodka

 

is

a distilled

beverage

composed

primarily of water and 

ethanol

,

sometimes with traces of impurities and flavorings. Traditionally, vodka is made by the distillation of 

fermented

cereal grains

or

 

potatoes

,

though some modern brands use other substances, such as fruits or

sugar.

40

% alcohol by

volume

ABV

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Production of vinegar

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What is vinegar?

Vinegar is a product resulting from the conversion of alcohol to acetic acid by acetic acid bacteria,

Acetobacter spp.The name is derived from French (Vin = wine; Aigre-sour or sharp).

When alcoholic fermentation occurs and later during acidifications many other compounds are produced.Depending mostly on the nature of the material fermented and some of these find their way into vinegar.

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Reactions also occur between these fermentation products

Ethyl acetate, for example, is formed from the reaction between acetic acid and ethanol.

It is these other compounds which give the various vinegars their organoleptic properties.The other compounds include:

non-volatile organic acids such as malic, citric, succinic and lactic acids; unfermented and unfermentable sugars; oxidized alcohol and acetaldelyde, acetoin, phosphate, chloride, and other ions.

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Uses of vinegar

Ancient uses:

Food condiment

Treatment of WoundsWide variety of illnesses such as plague, ringworms, burns, lamenessCleansing agent

It was used as a cosmetic aid.

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Modern uses:

Food condiment, sprinkled on certain foods such as fish at the table.(b) For pickling and preserving meats and vegetables; it can reduce the pH of food below that which even spore formers may not survive.

(c) Manufacture of sauces, salad dressings, mayonnaise, tomato productions, cheese dressings, mustard, and soft drinks.

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TYPES OF VINEGAR

The composition and specifications of various types of vinegars are defined by regulations set up by the governments of different countries .

In the United States, for example, vinegar should not contain less than 4.0% (w/v) acetic acid and not more than 0.5% ethanol (v/v).

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There are many different types of vinegars. The classification is usually based on the raw material used for its production. Malt vinegar, Wine vinegar, Apple cider vinegar, Balsamic vinegar, Fruit vinegar and many other types of vinegar exist in today’s global market. The most common types of vinegars and their origin are discussed

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Wine

Vinegar

Wine vinegar is made from red or white wine and is the most commonly used vinegar in Mediterranean countries and Central Europe. As with wine, there is a considerable range in quality. Better quality wine vinegars are matured in wood for up to two years and exhibit a complex, mellow flavor. Wine vinegar tends to have a lower acidity than that of white or cider vinegars. Germany, Austria, and the Netherlands. Although its flavor depends on the particular type of beer from which it is made, it is often described as having a malty taste. That produced in Bavaria, is a light golden color with a very sharp and not-overly-complex flavor. In Beer vinegar and Wine vinegar production only one type of fermentation takes place; for the conversion of ethanol in to acetic acid

.Fruit vinegars are made from fruit wines, usually without any additional flavoring. Common flavors of fruit vinegar include apple, black currant, raspberry, quince, and tomato. Typically, the flavors of the original fruits remain in the final product. Most fruit vinegars are produced in Europe, where there is a growing market for high-priced vinegars made solely from specific fruits (as opposed to non-fruit vinegars which are infused with fruits or fruit flavors).

Beer

Vinegar

Fruit

Vinegars

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Balsamic

Vinegar

Balsamic vinegar is an aromatic, aged type of vinegar traditionally crafted in the Modena and Reggio Emilia provinces of Italy from the concentrated juice, or must, of white grapes .It is very dark brown in color and its flavor is rich, sweet, and complex, with the finest grades being the product of years of aging in a successive number of casks made of various types of wood (including oak, mulberry, chestnut, cherry, juniper, ash, and acacia). Originally a product available only to the Italian upper classes, a cheaper form of balsamic vinegar became widely known and available around the world in the late twentieth century. True balsamic vinegar (which has Protected Designation of Origin) is aged for 12 to 25 years. Balsamic vinegars that have been aged for up to 100 years are available, though they are usually very expensive.

Malt vinegar is made by malting barley, causing the starch in the grain to turn to maltose. Then ale is brewed from the maltose and allowed to turn into vinegar, which is then aged. It is typically light brown in color.

Malt

Vinegar

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Rice

VinegarRice vinegar is most popular in the cuisines of East and Southeast Asia. It is available in “white” (light yellow), red, and black varieties. The Japanese prefer light rice vinegar for the preparation of sushi rice and salad dressings. Red rice vinegar traditionally is colored with red yeast rice. Black rice vinegar (made with black glutinous rice) is most popular in China, and it is also widely used in other East Asian countries. White rice vinegar has a mild acidity and a somewhat “flat”,

uncomplex flavor.

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ORGANISMS INVOLVED

The bacteria converting alcohol to acetic acid under natural conditions are film forming organisms on the surface of wine and beer.

The film was known as ‘mother of vinegar’ before its bacteriological nature became known.The bacteria were first described as

Mycoderma (viscous film) in 1822.Later other workers classified them in M. vini (forming film on wine) an M. acetic (forming film on beer).Pasteur confirmed that acetic acid is produced only in the presence of the bacteria, but he did not identify them.

The genus name

Acetobacter was put forward by Beijerinck in 1900.

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Although

Acetobacter spp are responsible for vinegar production, pure cultures are hardly

used, except in submerged fermentation because of the difficulty of isolating and maintaining the organisms. The only member of the genus which is not useful, if not positively harmful in vinegar production is Acetobacter xylinum which tends to produce slime

Recently a new species, Acetobacter europaeus, was described. Its distinguishing features are its strong tolerance of acetic acid of 4 to 8% in agar, and its absolute requirement of acetic acid for growth.

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Strains of acetic acid bacteria to be used in industrial production should:

a) tolerate high concentrations of acetic acid

b) require small amounts of nutrientc) not overoxidize the acetic acid formed

d) be high yielding in terms of the acetic acid produced.

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The biochemical processes for vinegar production

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1 gm of alcohol should yield 1.304 gm of acetic acid but this is hardly achieved and only in unusual cases is a yield of 1.1 attained.

From the reactions one mole of ethanol will yield one mole of acetic acid and mole of water.

It can be calculated that 1 gallon of 12% alcohol will yield 1 gal. of 12.4% acetic acid.Over-oxidation can occur and it is undesirable.

In over-oxidation acetic acid is converted to CO2 and H2O. It occurs when there is a lack or low level of alcohol. It occurs more frequently in submerged fermentations than in the trickle processes.

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Common production flowsheet of vinegar

Fruit juice

Fruits

Yeast

Alcohol Fermentation

Acetic Acid Fermentation

Ripening

Filtration

Pasterization

Bottling

Mother of vinegar

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MANUFACTURE OF VINEGAR

Three methods used for the production of vinegar are :

The Orleans Method (also known as the slow method).The Trickling (or quick) Method

Submerged Fermentation.

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The Orleans Method (also known as the slow method).

Slow process.

manufacture of high- quality vinegars.

also called continuous method.

T

his method, made famous by the French, was named after a small town in France named Orleans, known as the city of vinegars.

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1.The Orleans (or Slow) Method

The oldest method of vinegar production is the ‘let alone’ method in which wine left in open vats became converted to vinegar by acetic acid bacteria entering it from the atmosphere.

Later the wine was put in casks and left in the open field in the ‘fielding process’.A small amount of vinegar was introduced into a cask of wine to help initiate fermentation.

The introduced vinegar not only lowered the pH to the disadvantage of many other organisms but also introduced an inoculum of acetic acid bacteria.A thick film of acetic acid bacteria formed on the wine and converted it into vinegar in about five weeks.

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The process had a number of disadvantages

(a) It was slow in comparison with later methods (slow method).

(b) It was inefficient, yielding 75-85% of the theoretical amount.(c) The ‘mother of vinegar’ usually gradually filled the cask and effectively killed the process.

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2 .The Trickling Generators (Quick) Method

The Dutch Boerhaave who in 1732 devised the first trickling generator in which he used branches of vines, and grape stems as packing.

Improvements were made by a number of other people from time to time.Later ventilation holes were drilled at the bottom of the generator and provided a mechanical means for the repeated distribution of the alcohol acetic acid mixture over the packing.

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The heat generated by the exothermic reaction in the generator caused a draft which provided oxygen for the aerobic conversion of alcohol to acetic acid.

This latter model of the quick method (sometimes called the German method) enabled the production of vinegar in days instead of in weeks.

It remained in vogue unmodified for just over a century when several modifications were introduced in the Frings method, including: (a) forced aeration (b) temperature control

(c) semicontinuous operation.

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The modern vinegar generator consists of a tank constructed usually of wood preferably of cypress and occasionally of stainless steel.

A false bottom supports the coils of birchwood shavings and separates them from the collection chamber which occupies about one fifth of the total capacity of the generator (Fig. 14.1).

A pump circulates the alcohol-acetic acid mixture from the reservoir through a heat exchanger to the top of the generator where a spray mechanism distributes it over the packing.Air is forced through the false bottom up through the set-up.

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The cooling water in the heat exchanger is used to regulate the temperature in the generator so that it is between 29°C and 35°C; this is determined with thermometers placed at different levels of the generator.

The top of the generator is covered but provision exists for exhaust air to be let out.

Meters measure three parameters:(a) the circulation of the mash(b) the flow of cooling water through the heat exchange

(c) the amount of air delivered through the system.If the air flow rate is too high alcohol and vinegar are lost in effluent air.

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Operation of the generator:

The trickling or circulating Frings generator is reasonably efficient, achieving, when operating maximally, an efficiency of 91-92% and it is capable of producing 500–1000 gallons of 100-grain (i.e. 10%) vinegar every 24 hours.

Although the wood shavings soften with age, well-maintained generators can proceed without much attention for twenty to thirty years.

They are easy to maintain once airflow and recirculation rates as well as temperatures are maintained at the required level. The level of ethyl alcohol must be maintained so that it does not fall below 0.3-0.5% at any time.

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Complete exhaustion of the alcohol will lead to the death of the bacteria.

When wine and cider vinegar are made no nutrients need be added to the charge (i.e., the alcohol-containing material).

However, when white vinegar (produced from synthetic alcohol is used) nutrients e.g. simple low concentration sugar-mineral salts solution sometimes containing a little yeast extraction may be added.

Growth of the slime-forming Acetobacter xylinum is less with white vinegar (from pure alcohol) than with wine and cider vinegar.

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Generators for producing white vinegar therefore become blocked by slime much less quickly than those used for wine and cider vinegar, and can last far in excess of 20 to 30 years before the wood shavings are changed.

The finished acidity of the vinegar is about 12%; when it is higher, production drops off.

In order not to exceed this level of acidity, when drawing off vinegar, the amount of alcohol in the replacement should be such that the total amount of alcohol is less than 5%.

videohttps://www.youtube.com/watch?v=ZZJSpTIoHH8

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3. Submerged Generators

The common feature in all submerged vinegar production is that the aeration must be very vigorous as shortage of oxygen because of the highly acid conditions of submerged production, would result in the death of the bacteria within 30 seconds.

Furthermore, because a lot of heat is released (over 30,000 calories are released per gallon of ethanol) an efficient cooling system must be provided. All submerged vinegar is turbid because of the high bacterial content and have to be filtered.

Some submerged generators will be discussed below.

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3.1 Frings acetator

Most of the world’s vinegar is now produced with this

fermentor.

It consists of a stainless steel tank fitted with internal cooling coils and a high-speed agitator fitted through the bottom. Air is sucked in through an air-meter located at the top. It is then finely dispersed by the agitator and distributed throughout the liquid.

Temperature is maintained at 30°C, although some strains can grow at a higher temperature.

Foaming is interrupted with an automatic foam breaker. Essentially it is shaped like the typical aerated stirred tank

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It is operated batchwise and the cycle time for producing 12% vinegar is about 35 hours.

It is self aspirating, no compressed air being needed. The hollow rotor is installed on the shaft of a motor mounted under the fermentor, connected to an air suction pipe and surrounded by a stator.

It pumps liquid that enters the rotor from above outward through the channels of the stator that are formed by the wedges, thereby sucking air through the openings of the rotor and creating an air–liquid emulsion that is ejected outward at a given speed.This speed must be chosen adequately so that the turbulence of the stream causes a uniform distribution of the air over the whole cross section of the fermentor.

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Advantages

(a) The efficiency of the acetator is much higher than that of the trickling generator; the production rate of the acetator may be 10-fold higher than a trickling unit.

Values of 94% and 85% of the theoretical have been recorded for both the acetator and the trickling filter.

(b) The quality is more uniform and the inexplicable variability in quality noted for the trickling generator is absent.(c) A much smaller space is occupied (about one-sixth) in comparison with the trickling generator.(d) It is easy and cheap to change from one type of vinegar to another.

(e) Continuous production and automation can take place more easily with Frings acetator than with trickling.

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Disadvantages

(a) A risk exists of complete stoppage following death of bacteria from power failure even for a short time. Automatic stand-by generators have helped to solve this problem.

(b) It has a high rate of power consumption. Some authors have however argued that in fact in terms of power consumed per gallon of acetic produced the acetator is less power consuming.

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3.2 The cavitators

The cavitator was originally designed to treat sewage: it was then modified for vinegar production.

In many ways it resembled the acetator. However, the agitator was fixed to the top and finely dispersed air bubbles are introduced into the liquid. It operated on a continuous basis and was quite successful in producing cider and other vinegars as long as the grain strength was low.

It was not successful with high grain vinegar and the manufacture of the ‘cavitator’ was discontinued in 1969. Although some are still being used in Japan and the US.

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3.3 The tower fermentor

The tubular (tower) fermentor developed in the UK has been used on a commercial scale for the production of beer, vinegar, and citric acid.

The fermentor is two feet in diameter, about 20 feet tall in the tubular section with an expansion chamber of about four feet in diameter and six feet high.

It has a working volume of 3,000 liters and aeration is achieved by a stainless steel perforated plate covering the cross section of the tower and holding up the liquid. The charging wort is fed at the bottom. The unit can produce up to 1 million gallons (450,000 liters) of 5% acetic acid per annum. The system can be batch, semi or fully-continuous.

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PROCESSING OF VINEGAR

(a)

Clarification and bottling: Irrespective of the method of manufacture, vinegar for retailing is clarified by careful filtration using a filter aid such as diatomaceous earth.

Vinegar from trickling generators are however less turbid than those from submerged fermentations because a high proportion of the bacterial population responsible for the acetification is held back on the shavings. After clarification it is pasteurized at 60-65°C for 30 minutes.

Slide86

(b)

Concentration of vinegar:

Vinegar can be concentrated by freezing; thereafter the resulting slurry is centrifuged to separate the ice and produce the concentrate.With this method 200° grain (i.e., 20% w/v) acetic acid can be produced.

Concentration is necessitated by two considerations. One is the consequent reduction in transportation costs. The other is the need to prevent loss of activity of the vinegar when cucumbers were pickled in it after first being soaked in brine.

a grain (% acetic acid X 10)(analyzed by

volume)

1

grain

=64.79891

milligrams

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FERMENTED VEGETABLES

Slide88

FERMENTED VEGETABLES

Vegetable fermentation originated in the early years of human civilization and, even now, is widely used by many cultures.

Almost all vegetables can be fermented through natural processes because they harbor many types of lactic acid bacteria.Worldwide, most of the vegetable fermentation is done domestically.

The fermentation process for vegetables can result in nutritious foods that may be stored for extended periods, 1 year or more, without refrigeration. Examples of some fermented products and vegetables used currently for fermentation are sauerkraut and kimchi,(from cabbage), olives, cucumbers, carrots, celery, beans, peas, corn, okra, tomatoes, cauliflower, peppers, onions, citron, beets, turnips, radishes, chard, Brussels sprouts, and their blends.

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SAUERKRAUT

Country: Germany

Major Ingredients: Cabbage, SaltUsage: Salad, Side DishProduct Description: Fermented shredded cabbage. The product has a sour taste with a clean acid flavor.Microorganisms: L. mesenteroides

, Lactobacillus brevis, Pediococcus cerevisiae and Lb. plantarum,Starter Culture: Natural Microflora, commercial starter cultures are available. Sometimes backslopping.

Slide90

SAUERKRAUT

Slide91

SAUERKRAUT

Salting

The level of salting is critical to obtaining a satisfactory product, it must be within the range 2–3% w/w and is normally about 2.25%. Too little salt (<2%) and the product softens unacceptably, too much salt (>3%) and the correct microbial sequence is not obtained.The salt serves a number of purposes:

(i) it extracts moisture from the shredded cabbage by osmosis to form the brine in which the fermentation will take place; (ii) it helps to inhibit some of the natural microflora of the cabbage such as pseudomonads which would otherwise cause spoilage and helps to select for the lactic acid bacteria; (iii) it helps maintain the crisp texture of the cabbage by withdrawing water and inhibiting endogenous pectolytic enzymes which cause the product to soften;

(

iv) finally, salt contributes to the

flavour

of the product.

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SAUERKRAUT

Fermentation

The starter for sauerkraut production is usually the normal mixed flora of cabbage.The raw material has a large number of undesirable organisms and a small population of lactic acid bacteria (<1%)Among the lactic acid bacteria, most are Lactococcus spp. and Leuconostoc

spp., and a small fraction is Lactobacillus spp. and Pediococcus spp. During fermentation, sequential growth of these lactic acid bacteria occurs. The presence of 2.25% salt, large amounts of fermentable sugars (sucrose, hexoses, pentoses), an absence of oxygen, and a low fermentation temperature facilitate Leuconostoc spp., primarily

Leu

.

mesenteroides

, to grow rapidly

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SAUERKRAUT

Fermentation

When the acidity has reached approximately 1% (as lactic acid), growth of Leu. mesenteroides slows down. Then Lab. brevis starts growing rapidly until acid production reaches approximately 1.5%. Then

Ped. pentosaceus takes over and increases the acidity to approximately 1.8%. Finally, Lab. plantarum starts growing and brings the acid level to approximately 2%.

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SAUERKRAUT

Biochemistry

Leuconostoc spp. metabolize sucrose, hexoses, and some pentoses in the raw material to lactate, acetate, ethanol, CO2, and diacetyl. Lab. brevis (obligatory heterofermentative, such as Leuconostoc

spp.) ferments sucrose, hexoses, and pentoses to products similar to those by Leuconostoc spp. Ped. pentosaceus metabolizes hexoses to form mainly lactic acid and some pentoses to lactic acid, acetate, and ethanol.

Lab.

plantarum

also produces products from sucrose, hexoses, and

pentoses

similar to those by Ped.

pentosaceus

.

The characteristic flavor of sauerkraut is the result of the combined effects of lactate, acetate, ethanol, CO2, and diacetyl in proper amounts.

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KIMCHI

Region

: KoreaMajor Ingredients: Chinese Cabbage, Asian Radish, Red Pepper, Ginger, Garlic, SaltUsage: Salad, Side DishProduct Description: Fermented shredded cabbage. The product has a sour taste with a clean acid flavor.

Microorganisms: L. mesenteroides, Lactobacillus brevis, Pediococcus cerevisiae and Lb. plantarum,Starter Culture: Natural Microflora, commercial starter cultures are available.

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KIMCHI

Slide97

KIMCHI

Slide98

KIMCHI

Biochemistry and fermentation aspects of Kimchi are similar to sauerkraut.

The best taste is claimed after 3 days at 20C when the acidity is 0.6% and the pH around 4.2. Leuconostoc mesenteroides is the principal organism responsible for the fermentation D

ominance of Lactobacillus plantarum is regarded as a defect which results in an excessively sour product.

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DIFFERENCE BETWEEN KIMCHI AND SAUERKRAUT

Sauerkraut

ParameterKimchi

2%Acid content0.6%2-3%

Salt Content

3-3.5%

Min 7 days

Fermentation Time

3-4

days

Only Cabbage and Salt

Ingredients

Contains added ingredients for flavor

Finely ShreddedCabbageLarge Chunks

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OLIVES

Region

: MediterraneanMajor Ingredients: Olives, BrineUsage: Salad, Side DishMicroorganisms: L.mesenteroides, Lactobacillus brevis,

Pediococcus cerevisiae and Lb. plantarum,Starter Culture: Natural Microflora, commercial starter cultures are available.

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OLIVES

Slide102

OLIVES

Fermentation

The initial pH of the fermentation can be above 7 depending on how much washing was done after the NaOH treatment. As a consequence, the initial microflora during fermentation can include a variety of gram-positive bacilli (Bacillus species) and gram-negative enteric bacteria (Enterobacter, Citrobacter,

Klebsiella, and Escherichia). As organic acids accumulate and the pH decreases below 6, the LAB, principally Lb. plantarum, dominate the fermentation to the exclusion of the other gram-positive and gram-negative microbes. Yeast species may also be present (Candida, Pichia, Saccharomyces, and others) and

contribute desirable flavor characteristics to the brined olives.

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PICKLES

Region

: North America, GermanyMajor Ingredients: Cucumber, Spices, Dill etcUsage: Salad, Side DishMicroorganisms:

Lactobacillus brevis, Pediococcus cerevisiae and Lb. plantarum,Starter Culture: Natural Microflora, commercial starter cultures are available. Sometimes backslopping.

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PICKLES

Slide105

Definition:

“It is the process of preserving food by anaerobic fermentation in brine to produce lactic acid, or marinating and storing it in an acid solution, usually vinegar (acetic acid). The resulting food is called a PICKLE”.

The term pickle is derived from the Dutch word pekel

, Canada, the word pickle alone almost always refers to a pickled cucumber. Other types of pickles will be described as "pickled onion," "pickled cauliflower," etc.

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SALIENT FEATURES:

Brining or Corning.

Food salty or sour taste. PH less than 4.6. 

Preserve perishable foods Antimicrobial herbs and spices.

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Pickling Equipment:

Utensils made of zinc, iron, brass, copper, or galvanized metal should not be used.

For fresh-pack pickling large container made of stainless steel, glassware.For fermenting and brining, a crock or stone jar, an un chipped enamel-lined pan, a glass jar, a bowl, used for small quantities.

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Pickles with Salt Content:

Fresh-pack pickles may be prepared safely with reduced or no salt; they are acidified quickly with vinegar.

salt used in making brine pickles and fermented sauerkraut .The function of salt in fermented foods is to encourage the growth of desirable bacteria

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Key ingredients in

pickling

I

ngredient

Why used???

Salt

Acts as a preservative by encouraging the growth of desirable bacteria (and inhibiting undesirable bacteria) which in turn produce lactic acid, a preservative.

Helps draw juices and sugar from the produce to make a brine.

Adds flavor and crispness.

Vinegar

Gives pickles a tart taste.

Acts as a preservative due to the acidity of vinegar.

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Sugar

Sweetens taste; counteracts vinegar.

Spices/Herbs

Adds flavor

Water

Makes liquid portion of brine.

Alum

Improves pickle firmness for fermented pickles; does not

improved

firmness of quick-process pickles.

Lime

Improves pickle firmness.

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Trouble-shooting pickles

NOTE: These pickles are safe to eat even though they may not look

too good.

This happened:

Because of this:

Shriveled pickles

Vinegar or salt solution too strong.

Overcooking or over processing.

Hollow pickles

Poory

developed cucumbers.

Cucumbers too ripe.

Cucumbers held too long before pickling.

Fermentation too rapid.

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SHALGAM

Shalgam

is a traditional Turkish fermented beverage in which mainly lactic acid bacteria play an important role. It is a red colored, turbid and sour soft beverage produced by mixing of turnip, purple carrot, sourdough, salt, water and fermenting for 10-12 days. Red beet can also be used as a raw-material.

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Microorganisms

The microorganisms influenced in the fermentation obtained from sourdough. These are L.

sanfranciscensis, L. pontis, L. brevis, L. plantarum, L. alimentarius,L. fructivorans, L. reuteri

, L. fermentum and Saccharomyces cerevisiae and to less extent Saccharomyces exiguous, Candida krusei and Candida milleri.

Slide114

Definition

and production

According to the Turkish Standards Institution, shalgam is defined as a beverage produced by lactic acid fermentation of black carrot (Daucus carota L.), turnip (Brassica rapa L.), salt and extract of sourdough and bulgur flour. For

shalgam production, no standard manufacturing technique is available and many different methods can be used in production.

Slide115

Production

Slide116

Production