Vinegar
Vinegar is a liquid consisting of about 5–20% acetic acid (CH3COOH), water, and other trace chemicals, which may include flavorings. The acetic acid is produced by the fermentation of ethanol by acetic acid bacteria. Vinegar is now mainly used as a cooking ingredient, or in pickling. As the most easily manufactured mild acid, it has historically had a great variety of industrial, medical, and domestic uses, some of which (such as its use as a general household cleaner) are still commonly practiced today.
Commercial vinegar is produced either by a fast or a slow fermentation processes. In general, slow methods are used in traditional vinegars where fermentation proceeds slowly over the course of a few months or up to a year. The longer fermentation period allows for the accumulation of a non-toxic slime composed of acetic acid bacteria. Fast methods add mother of vinegar (bacterial culture) to the source liquid before adding air to oxygenate and promote the fastest fermentation. In fast production processes, vinegar may be produced between 20 hours to three days.
The conversion of ethanol (CH3CH2OH) and oxygen (O2) to acetic acid (CH3COOH) takes place by the following reaction:
Vinegar has been made and used by people for thousands of years. Traces of it have been found in Egyptian urns from around 3000 BC.
Apple cider vinegar is made from cider or apple must, and has a brownish-gold color. It is sometimes sold unfiltered and unpasteurized with the mother of vinegar present, as a natural product. It can be diluted with fruit juice or water or sweetened (usually with honey) for consumption as a health beverage.
Balsamic vinegar is an aromatic aged vinegar produced in the Modena and Reggio Emilia provinces of Italy. The original product—Traditional Balsamic Vinegar—is made from the concentrated juice, or must, of white Trebbiano grapes. It is very dark brown, rich, sweet, and complex, with the finest grades being aged in successive casks made variously of oak, mulberry, chestnut, cherry, juniper, and ash wood. Originally a costly product available to only the Italian upper classes, traditional balsamic vinegar is marked "tradizionale" or "DOC" to denote its Protected Designation of Origin status, and is aged for 12 to 25 years. A cheaper non-DOC commercial form described as "aceto balsamico di Modena" (balsamic vinegar of Modena) became widely known and available around the world in the late 20th century, typically made with concentrated grape juice mixed with a strong vinegar, then coloured and slightly sweetened with caramel and sugar.
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