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Microoxygenation
Micro-oxygenation is a process used in winemaking to introduce oxygen into wine in a controlled manner. Developed in 1991 by Patrick DuCournau, working with the exceptionally tannic grape Tannat in Madiran, the process gained usage in modern winemaking following the 1996 authorization by the European Commission. Today, the technique is widely employed in Bordeaux, as well as at least 11 different countries, including the United States and Chile. J. Robinson (ed) ''"The Oxford Companion to Wine"'' Third Edition pg 442-443 Oxford University Press 2006 Process The process of micro-oxygenation involves a large two-chamber device with valves interconnected to a tank of oxygen. In the first chamber, the oxygen is calibrated to match the volume of the wine. In the second chamber, the oxygen is injected into the wine through a porous ceramic stone located at the bottom of the chamber. The dosage is controlled and can range anywhere from .75 to 3 cubic centimetres per liter of wine. Th ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Wine Colour
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] |
Tannin (wine)
The phenolic content in wine refers to the phenolic compounds— natural phenol and polyphenols—in wine, which include a large group of several hundred chemical compounds that affect the taste, color and mouthfeel of wine. These compounds include phenolic acids, stilbenoids, flavonols, dihydroflavonols, anthocyanins, flavanol monomers (catechins) and flavanol polymers (proanthocyanidins). This large group of natural phenols can be broadly separated into two categories, flavonoids and non-flavonoids. Flavonoids include the anthocyanins and tannins which contribute to the color and mouthfeel of the wine. The non-flavonoids include the stilbenoids such as resveratrol and phenolic acids such as benzoic, caffeic and cinnamic acids. Origin of the phenolic compounds The natural phenols are not evenly distributed within the fruit. Phenolic acids are largely present in the pulp, anthocyanins and stilbenoids in the skin, and other phenols (catechins, proanthocyanidins and flavonols) ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Carboxypyranoanthocyanidin
The pyranoanthocyanins are a type of pyranoflavonoids. They are chemical compounds formed in red wines by yeast during fermentation processes or during controlled oxygenation processes during the aging of wine. The different classes of pyranoanthocyanins are carboxypyranoanthocyanins, methylpyranoanthocyanins, pyranoanthocyanin-flavanols, pyranoanthocyanin-phenols, portisins, oxovitisins and pyranoanthocyanin dimers; their general structure includes an additional ring (formed between the OH group at C-5 and the C-4 of the anthocyanin pyranic ring) that may have different substituents linked directly at C-10. Examples * Carboxypyranoanthocyanidins, can be considered markers of microoxygenation techniques * Hydroxyphenyl-pyranoanthocyanins * Vitisin A and B * Pinotins * Portosins (vinylpyranoanthocyanins) Vitisin A type * Cyanidin-3-O-glucoside-pyruvic acid (m/z of +H ion:517, λmax 506 nm) * Cyanidin-3-O-acetylglucoside-pyruvic acid (559 - 507) * Cyanidin-coumar ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Phenolic Content In Wine
The phenolic content in wine refers to the phenolic compounds—natural phenol and polyphenols—in wine, which include a large group of several hundred chemical compounds that affect the taste, color and mouthfeel of wine. These compounds include phenolic acids, stilbenoids, flavonols, dihydroflavonols, anthocyanins, flavanol monomers (catechins) and flavanol polymers (proanthocyanidins). This large group of natural phenols can be broadly separated into two categories, flavonoids and non-flavonoids. Flavonoids include the anthocyanins and tannins which contribute to the color and mouthfeel of the wine. The non-flavonoids include the stilbenoids such as resveratrol and phenolic acids such as benzoic, caffeic and cinnamic acids. Origin of the phenolic compounds The natural phenols are not evenly distributed within the fruit. Phenolic acids are largely present in the pulp, anthocyanins and stilbenoids in the skin, and other phenols (catechins, proanthocyanidins and flavonols) in ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Aroma Of Wine
The aromas of wine are more diverse than its flavours. The human tongue is limited to the primary tastes perceived by taste receptors on the tongue – sourness, bitterness, saltiness, sweetness and savouriness. The wide array of fruit, earthy, leathery, floral, herbal, mineral, and woodsy flavour present in wine are derived from aroma notes sensed by the olfactory bulb.J. Robinson (ed) ''"The Oxford Companion to Wine"'' Third Edition p. 683 Oxford University Press 2006 In wine tasting, wine is sometimes smelled before taking a sip in order to identify some components of the wine that may be present. Different terms are used to describe what is being smelled. The most basic term is aroma which generally refers to a "pleasant" smell as opposed to odour which refers to an unpleasant smell or possible wine fault. The term aroma may be further distinguished from bouquet which generally refers to the smells that arise from the chemical reactions of fermentation and aging o ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Winemaking
Winemaking or vinification is the production of wine, starting with the selection of the fruit, its fermentation into alcohol, and the bottling of the finished liquid. The history of wine-making stretches over millennia. The science of wine and winemaking is known as oenology. A winemaker may also be called a vintner. The growing of grapes is viticulture and there are many varieties of grapes. Winemaking can be divided into two general categories: still wine production (without carbonation) and sparkling wine production (with carbonation – natural or injected). Red wine, white wine, and rosé are the other main categories. Although most wine is made from grapes, it may also be made from other plants. (See fruit wine.) Other similar light alcoholic drinks (as opposed to beer or Liquor, spirits) include mead, made by fermenting Honey#Fermentation, honey and water, cider ("apple cider"), made by fermenting the Apple juice, juice of apples, and perry ("pear cider"), made ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Sulfides
Sulfide (British English also sulphide) is an inorganic anion of sulfur with the chemical formula S2− or a compound containing one or more S2− ions. Solutions of sulfide salts are corrosive. ''Sulfide'' also refers to chemical compounds large families of inorganic and organic compounds, e.g. lead sulfide and dimethyl sulfide. Hydrogen sulfide (H2S) and bisulfide (SH−) are the conjugate acids of sulfide. Chemical properties The sulfide ion, S2−, does not exist in aqueous alkaline solutions of Na2S. Instead sulfide converts to hydrosulfide: :S2− + H2O → SH− + OH− Upon treatment with an acid, sulfide salts convert to hydrogen sulfide: :S2− + H+ → SH− :SH− + H+ → H2S Oxidation of sulfide is a complicated process. Depending on the conditions, the oxidation can produce elemental sulfur, polysulfides, polythionates, sulfite, or sulfate. Metal sulfides react with halogens, forming sulfur and metal salts. :8 MgS + 8 I2 → S8 + 8&n ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Yeast (wine)
The role of yeast in winemaking is the most important element that distinguishes wine from fruit juice. In the absence of oxygen, yeast converts the sugars of the fruit into alcohol and carbon dioxide through the process of fermentation.Jeff Cox ''"From Vines to Wines: The Complete Guide to Growing Grapes and Making Your Own Wine"'' pp. 133–36 Storey Publishing 1999 The more sugars in the grapes, the higher the potential alcohol level of the wine if the yeast are allowed to carry out fermentation to dryness.D. Bird ''"Understanding Wine Technology"'' pp. 67–73 DBQA Publishing 2005 Sometimes winemakers will stop fermentation early in order to leave some residual sugars and sweetness in the wine such as with dessert wines. This can be achieved by dropping fermentation temperatures to the point where the yeast are inactive, sterile filtering the wine to remove the yeast or fortification with brandy or neutral spirits to kill off the yeast cells. If fermentation is unintentiona ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Polymerization
In polymer chemistry, polymerization (American English), or polymerisation (British English), is a process of reacting monomer, monomer molecules together in a chemical reaction to form polymer chains or three-dimensional networks. There are many forms of polymerization and different systems exist to categorize them. In chemical compounds, polymerization can occur via a variety of reaction mechanisms that vary in complexity due to the functional groups present in the reactants and their inherent steric effects. In more straightforward polymerizations, alkenes form polymers through relatively simple free-radical reaction, radical reactions; in contrast, reactions involving substitution at a carbonyl group require more complex synthesis due to the way in which reactants polymerize. Alkanes can also be polymerized, but only with the help of strong acids. As alkenes can polymerize in somewhat straightforward radical reactions, they form useful compounds such as polyethylene and p ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Aeration
Aeration (also called aerification or aeriation) is the Systems engineering process, process by which air is circulated through, mixed with or solvation, dissolved in a liquid or other substances that act as a fluid (such as soil). Aeration processes create additional surface area in the mixture, allowing greater chemical or suspension reactions. Aeration of liquids Methods Aeration of liquids (usually water) is achieved by: * passing air through the liquid by means of the Venturi tube, Aeration Turbine, aeration turbines or compressed air which can be combined with diffuser(s) air stone(s), as well as fine bubble diffusers, coarse bubble diffusers or linear aeration tubing. Ceramics are suitable for this purpose, often involving dispersion of fine air or gas bubbles through the porous ceramic into a liquid. The smaller the bubbles, the more gas is exposed to the liquid increasing the gas transfer efficiency. Diffusers or spargers can also be designed into the system to cause turbu ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Oak (wine)
Oak is used in winemaking to vary the color, flavor, tannin profile and texture of wine. It can be introduced in the form of a barrel during the fermentation or aging periods, or as free-floating chips or staves added to wine fermented in a vessel like stainless steel. Oak barrels can impart other qualities to wine through evaporation and low level exposure to oxygen.J. Robinson ''Jancis Robinson's Wine Course'' Third Edition pg 91-93 Abbeville Press 2003 History In early wine history, the amphora was the vessel of choice for the storage and transportation of wine. Due to the perishable nature of wood material it is difficult to trace the usage of barrels in history. The Greek historian Herodotus noted that ancient Mesopotamians used barrels made of palm wood to transport wine along the Euphrates. Palm is a difficult material to bend and fashion into barrels, however, and wine merchants in different regions experimented with different wood styles to find a better wood source. ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Wine Faults
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] |
