January 2009
ARCHIVES.
January 2009
 
VINEGAR PRODUCTION
It is likely that the first vinegar used by ancient peoples was simply spoiled wine. In fact the word vinegar comes from the French words “vin” (“wine”) and “aigre” (“sour”). Wine making dates back at least 10,000 years and it can be assumed that vinegar making goes back just as far. Evidence exists indicating that most ancient peoples who used vinegar derived it from wines made from the numerous fermentable materials available in the areas where they lived such as Grapes, Apples, Dates…..Vinegar is a solution of which acetic acid is the essential ingredient. The others being water and various impurities By F.D.A standards. Vinegar must contain at least 4% acetic acid. The acetic acid is produced from ethanol by micro organisms. The conversion of ethanol to acetic acid is relatively simple compared to other biological processes. It is a two-step reaction.
Ethanol is converted to acetaldehyde and water EQU 1 and 2. The resulting hydrated acetaldehyde is than dehydrogenated to acetic acid as shown in EQU 3. The conversion of ethanol to acetic acid is exothermic. One gram of ethanol theoretically produces1.304gm of acetic acid and 0.391gm of water

Acetic acid organisms

For Thousands of years, people who produced vinegar were making use of acetic acid producing organisms, although the microbiological nature of the vinegar process was not suspected until F.T.KUTZING theorized in 1837 that microorganisms converted ethanol to acetic acid. His theory was confirmed by Pasteur in 1868 although the acetic acid producing organisms or acetobacter were among the first bacteria to be studied.      
Commercial Vinegar Production

A-Trickling generators
B-Submerged culture generators

A-Trickling generators:
The most widely used submerged culture vinegar generator is based on acetator. It is a fully engineered stainless steel fermentor that is equipped with a high speed bottom-entering agitator, temperature control and a foam breaker. The unique feature of this equipment is it is highly efficient method of supplying air. This is accomplished by means of a high-velocity self-aspirating rotor on the bottom of the tank that pulls air in through a pipe that is connected to a rotameter and control value on the out side.
Comparison of trickling submerged operations. The desirable feature and advantages of the acetator over the trickling generator are numerous:-


1. About one-sixth the amount of space is required to produce an equal quantity of vinegar.

2. Invested capital as compared with productive capacity is much lower than for packed generator operations.

3. The efficiency is greater and yields are 5-8% higher.

4. It is easy to switch from one type of vinegar to another and to start up to full production

5. Generator can be highly automated.
C/ Other vinegar generators

1-Yeomans cavitator:-
It is a submerged culture type system very similar to the acetator but differing in the manner in which air is supplied.

2-Bourgeois process:-
It is a submerged culture system used in Spain and Italy in which compressed air is distributed to the tanks through a rotor. It is a two-generator system where one is used to supply inoculums. The other batches are finished when all alcohol has been converted to acetic acid then the entire contents of the tank are withdrawn. Since vinegar bouquet and flavor are attributed to ester some alcohol is subsequently added to the finished product to enhance its quality through esterification. The bourgeois process is satisfactory only where low acidities and slow production rate can be tolerated.

3-Fardon process:- It is generators are also of the submerged culture type. Liquid is pumped from the tank through a venture nozzle for aeration and returned like the bourgeois process used mainly in Africa for making malt vinegar. 

4-The tower fermentor:- It is relatively recent development in aeration systems patented in England. It is a continuous trickling type generator. 

Popular types of vinegar

1-White distilled vinegar (Ethanol used as the raw material that has been distilled)

2-Cider vinegar (Made from the fermented juice of apple containing 11-12% soluble solids)

3-Date vinegar (Made from the fermented juice of date)

4-Wine vinegar:-Lower quality grape wines are commonly used for acetous fermentation to wine vinegar.

5-Malt vinegar:-It is made by the alcoholic and acetous fermentation of a malt mash or mash containing corn and barley in addition to the malt.

Processing of vinegar

Fermentation the juice --->Acidification
                                          (Used acetic acid organisms)
---->Filtration and clarification
---->Bottling ----->Concentration of vinegar
 
Diagram