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Volatile Acidity
A wine fault or defect is an unpleasant characteristic of a wine often resulting from poor winemaking practices or storage conditions, and leading to wine spoilage. Many of the compounds that cause wine faults are already naturally present in wine but at insufficient concentrations to be of issue. In fact, depending on perception, these concentrations may impart positive characters to the wine. However, when the concentration of these compounds greatly exceeds the sensory threshold, they replace or obscure the flavors and aromas that the wine should be expressing (or that the winemaker wants the wine to express). Ultimately the quality of the wine is reduced, making it less appealing and sometimes undrinkable.M. Baldy: ''"The University Wine Course", Third Edition, pp. 37-39, 69-80, 134-140. The Wine Appreciation Guild 2009 . There are many causes for the perception in wine faults, including poor hygiene at the winery, excessive or insufficient exposure of the wine to oxygen, exce ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Wine
Wine is an alcoholic drink typically made from fermented grapes. Yeast consumes the sugar in the grapes and converts it to ethanol and carbon dioxide, releasing heat in the process. Different varieties of grapes and strains of yeasts are major factors in different styles of wine. These differences result from the complex interactions between the biochemical development of the grape, the reactions involved in fermentation, the grape's growing environment (terroir), and the wine production process. Many countries enact legal appellations intended to define styles and qualities of wine. These typically restrict the geographical origin and permitted varieties of grapes, as well as other aspects of wine production. Wines not made from grapes involve fermentation of other crops including rice wine and other fruit wines such as plum, cherry, pomegranate, currant and elderberry. Wine has been produced for thousands of years. The earliest evidence of wine is from the Caucasus ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Sulfur Dioxide
Sulfur dioxide (IUPAC-recommended spelling) or sulphur dioxide (traditional Commonwealth English) is the chemical compound with the formula . It is a toxic gas responsible for the odor of burnt matches. It is released naturally by volcanic activity and is produced as a by-product of copper extraction and the burning of sulfur- bearing fossil fuels. Structure and bonding SO2 is a bent molecule with ''C''2v symmetry point group. A valence bond theory approach considering just ''s'' and ''p'' orbitals would describe the bonding in terms of resonance between two resonance structures. The sulfur–oxygen bond has a bond order of 1.5. There is support for this simple approach that does not invoke ''d'' orbital participation. In terms of electron-counting formalism, the sulfur atom has an oxidation state of +4 and a formal charge of +1. Occurrence Sulfur dioxide is found on Earth and exists in very small concentrations and in the atmosphere at about 1 ppm. On other planets, ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Malolactic Fermentation
Malolactic conversion (also known as malolactic fermentation or MLF) is a process in winemaking in which tart-tasting malic acid, naturally present in grape must, is converted to softer-tasting lactic acid. Malolactic fermentation is most often performed as a secondary fermentation shortly after the end of the primary fermentation, but can sometimes run concurrently with it. The process is standard for most red wine production and common for some white grape varieties such as Chardonnay, where it can impart a "buttery" flavor from diacetyl, a byproduct of the reaction. The fermentation reaction is undertaken by the family of lactic acid bacteria (LAB); ''Oenococcus oeni'', and various species of ''Lactobacillus'' and ''Pediococcus''. Chemically, malolactic fermentation is a decarboxylation, which means carbon dioxide is liberated in the process.K. Fugelsang, C. Edwards ''Wine Microbiology'' Second Edition pgs 29-44, 88-91, 130-135, 168-179 Springer Science and Business Media, New ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Sparkling (wine)
Sparkling wine is a wine with significant levels of carbon dioxide in it, making it fizzy. While the phrase commonly refers to champagne, European Union countries legally reserve that term for products exclusively produced in the Champagne region of France. Sparkling wine is usually either white or rosé, but there are examples of red sparkling wines such as the Italian Brachetto, Bonarda and Lambrusco, and the Australian sparkling Shiraz. The sweetness of sparkling wine can range from very dry ''brut'' styles to sweeter ''doux'' varieties (French for 'hard' and 'soft', respectively).J. Robinson (ed) ''"The Oxford Companion to Wine"'' Third Edition pp 656–660, Oxford University Press 2006 . The sparkling quality of these wines comes from its carbon dioxide content and may be the result of natural fermentation, either in a bottle, as with the traditional method, in a large tank designed to withstand the pressures involved (as in the Charmat process), or as a result of simple ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Wine's Color
The color of wine is one of the most easily recognizable characteristics of wines. Color is also an element in wine tasting since heavy wines generally have a deeper color. The accessory traditionally used to judge the wine color was the tastevin, a shallow cup allowing one to see the color of the liquid in the dim light of a cellar. The color is an element in the classification of wines. Color origins The color of the wine mainly depends on the color of the drupe of the grape variety. Since pigments are localized in the center of the grape drupe, not in the juice, the color of the wine depends on the method of vinification and the time the must is in contact with those skins, a process called maceration. The Teinturier grape is an exception in that it also has a pigmented pulp. The blending of two or more varieties of grapes can explain the color of certain wines, like the addition of Rubired to intensify redness. Red drupe grapes can produce white wine if they are quickly ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Browning In Red Wine
Oxidation and reduction in red wines can lead to a particularly undesirable brick red color in red wines (or an "orangey" color in white wines). This process is sometimes referred to as browning. In chemical terms, this is called a redox reaction because first the color of the wine deepens after fermentation through oxidation, and then the color begins to brown after bottling through reduction. Browning is not strictly considered a bad thing in every wine that is produced, as sometimes the oxidation process can contribute to the style of the wine in a positive and desirable way. Generally speaking, however, browning is a sign of the wine going stale from too much exposure to oxygen. Although wine that has gone bad is typically associated with the smell and taste of vinegar or unwanted effervescence, oxidation itself can actually lead to "nutty", "applesauce", and "burnt marshmallow" aromas. The sharp vinegar component comes from acetic acid formed through bacterial processes ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Cork Taint
Cork taint is a broad term referring to a wine fault characterized by a set of undesirable smells or tastes found in a bottle of wine, especially spoilage that can only be detected after bottling, aging and opening. Though modern studies have shown that other factors can also be responsible for taint – including wooden barrels, storage conditions and the transport of corks and wine – the cork stopper is normally considered to be responsible, and a wine found to be tainted on opening is said to be corked or "corky". Cork taint can affect wines irrespective of price and quality level. The chief cause of cork taint is the presence of the chemical compounds 2,4,6-trichloroanisole (TCA) or 2,4,6-tribromoanisole (TBA) in the wine, which in many cases will have been transferred from the cork, but which also can have been transferred through the cork rather than from it. TCA is a compound which does not occur naturally. It is created when some fungi are treated with chlor ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Ethyl Acetate
Ethyl acetate ( systematically ethyl ethanoate, commonly abbreviated EtOAc, ETAC or EA) is the organic compound with the formula , simplified to . This colorless liquid has a characteristic sweet smell (similar to pear drops) and is used in glues, nail polish removers, and in the decaffeination process of tea and coffee. Ethyl acetate is the ester of ethanol and acetic acid; it is manufactured on a large scale for use as a solvent. Production and synthesis Ethyl acetate was first synthesized by the Count de Lauraguais in 1759 by distilling a mixture of ethanol and acetic acid. In 2004, an estimated 1.3 million tonnes were produced worldwide. The combined annual production in 1985 of Japan, North America, and Europe was about 400,000 tonnes. The global ethyl acetate market was valued at $3.3 billion in 2018. Ethyl acetate is synthesized in industry mainly via the classic Fischer esterification reaction of ethanol and acetic acid. This mixture converts to the ester in ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Rancio
This glossary of winemaking terms lists some of terms and definitions involved in making wine, fruit wine, and mead. A ;Acetaldehyde : The main aldehyde found in wines, most notably Sherry. ;Acetic acid : One of the primary volatile acids in wine. ;Acetification : The process through which acetic acid is produced in wine. ;Acetobacter : A bacterium found in wine that causes acetification resulting in the conversion of wine to vinegar. ;Acidity : The quality of wine that gives it its crispiness and vitality. A proper balance of acidity must be struck with the other elements of a wine, or else the wine may be said to be too sharp – having disproportionately high levels of acidity – or too flat – having disproportionately low levels of acidity. The three main acids found in wine are tartaric acid, malic acid and lactic acid. The first two come from the grapes and the third from Malolactic fermentation which often occurs in the winemaking process. ; Active acidity :The concentr ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Sherry
Sherry ( es, jerez ) is a fortified wine made from white grapes that are grown near the city of Jerez de la Frontera in Andalusia, Spain. Sherry is produced in a variety of styles made primarily from the Palomino grape, ranging from light versions similar to white table wines, such as Manzanilla and fino, to darker and heavier versions that have been allowed to oxidise as they age in barrel, such as Amontillado and oloroso. Sweet dessert wines are also made from Pedro Ximénez or Moscatel grapes, and are sometimes blended with Palomino-based sherries. Under the official name of Jerez-Xérès-Sherry, it is one of Spain's wine regions, a Denominación de Origen Protegida (DOP). The word ''sherry'' is an anglicisation of Xérès (Jerez). Sherry was previously known as '' sack'', from the Spanish ''saca'', meaning "extraction" from the solera. In Europe, "sherry" has protected designation of origin status, and under Spanish law, all wine labelled as "sherry" must legally come fro ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Acetaldehyde
Acetaldehyde (IUPAC systematic name ethanal) is an organic chemical compound with the formula CH3 CHO, sometimes abbreviated by chemists as MeCHO (Me = methyl). It is a colorless liquid or gas, boiling near room temperature. It is one of the most important aldehydes, occurring widely in nature and being produced on a large scale in industry. Acetaldehyde occurs naturally in coffee, bread, and ripe fruit, and is produced by plants. It is also produced by the partial oxidation of ethanol by the liver enzyme alcohol dehydrogenase and is a contributing cause of hangover after alcohol consumption. Pathways of exposure include air, water, land, or groundwater, as well as drink and smoke. Consumption of disulfiram inhibits acetaldehyde dehydrogenase, the enzyme responsible for the metabolism of acetaldehyde, thereby causing it to build up in the body. The International Agency for Research on Cancer (IARC) has listed acetaldehyde as a Group 1 carcinogen. Acetaldehyde is "one of the mos ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Recognition Threshold
Recognition may refer to: *Award, something given in recognition of an achievement Machine learning *Pattern recognition, a branch of machine learning which encompasses the meanings below Biometric *Recognition of human individuals, or biometrics, used as a form of identification and access control **Facial recognition system, a system to identify individuals by their facial characteristics **Fingerprint recognition, automated method of verifying a match between two human fingerprints **Handwritten biometric recognition, identifies the author of specific handwriting, offline (static) or in real-time (dynamic) **Iris recognition, a method of biometric identification Linguistic *Language identification, the problem of identifying which natural language given content is in *Natural language understanding, the parsing of the meaning of text *Speech recognition, the conversion of spoken words into text *Speaker recognition, the recognition of a speaker from their voice Textual ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
