Malolactic
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Malolactic
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 ...
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Malolactic Spotting
Malolactic conversion (also known as malolactic fermentation or MLF) is a process in winemaking in which Tart (flavor), 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 (wine), secondary fermentation shortly after the end of the primary fermentation (wine), 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 ...
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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 ...
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Fermentation (wine)
The process of fermentation in winemaking turns grape juice into an alcoholic beverage. During fermentation, yeasts transform sugars present in the juice into ethanol and carbon dioxide (as a by-product). In winemaking, the temperature and speed of fermentation are important considerations as well as the levels of oxygen present in the must at the start of the fermentation. The risk of stuck fermentation and the development of several wine faults can also occur during this stage, which can last anywhere from 5 to 14 days for ''primary fermentation'' and potentially another 5 to 10 days for a '' secondary fermentation''. Fermentation may be done in stainless steel tanks, which is common with many white wines like Riesling, in an open wooden vat, inside a wine barrel and inside the wine bottle itself as in the production of many sparkling wines. History The natural occurrence of fermentation means it was probably first observed long ago by humans.H. Johnson: ''Vintage: The Story ...
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Lactic Acid Bacteria
Lactobacillales are an order of gram-positive, low-GC, acid-tolerant, generally nonsporulating, nonrespiring, either rod-shaped (bacilli) or spherical (cocci) bacteria that share common metabolic and physiological characteristics. These bacteria, usually found in decomposing plants and milk products, produce lactic acid as the major metabolic end product of carbohydrate fermentation, giving them the common name lactic acid bacteria (LAB). Production of lactic acid has linked LAB with food fermentations, as acidification inhibits the growth of spoilage agents. Proteinaceous bacteriocins are produced by several LAB strains and provide an additional hurdle for spoilage and pathogenic microorganisms. Furthermore, lactic acid and other metabolic products contribute to the organoleptic and textural profile of a food item. The industrial importance of the LAB is further evidenced by their generally recognized as safe (GRAS) status, due to their ubiquitous appearance in food and thei ...
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Wine Fault
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 ...
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Secondary Fermentation (wine)
Secondary fermentation is a process commonly associated with winemaking,J. Robinson (ed) ''"The Oxford Companion to Wine"'' Third Edition pg 618 Oxford University Press 2006 which entails a second period of fermentation in a different vessel than the one used to start the fermentation process. An example of this would be starting fermentation in a carboy or stainless steel tank and then moving it over to oak barrels. Rather than being a separate, second fermentation, this is most often one single fermentation period that is conducted in multiple vessels. However, the term does also apply to procedures that could be described as a second and distinct fermentation period. In wine production In sparkling wine production, the secondary fermentation often takes places in the wine bottle that the wine will be sold in. This is most commonly known as the ''méthode champenoise'' or "Champagne method" after the region most noted for sparkling wine production. When the base wine (or '' cu ...
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Diacetyl
Diacetyl (IUPAC systematic name: butanedione or butane-2,3-dione) is an organic compound with the chemical formula (CH3CO)2. It is a yellow liquid with an intensely buttery flavor. It is a vicinal diketone (two C=O groups, side-by-side). Diacetyl occurs naturally in alcoholic beverages and is added as a flavoring to some foods to impart its buttery flavor. Chemical structure A distinctive feature of diacetyl (and other vicinal diketones) is the long C–C bond linking the carbonyl centers. This bond distance is about 1.54 Å, compared to 1.45 Å for the corresponding C–C bond in 1,3-butadiene. The elongation is attributed to repulsion between the polarized carbonyl carbon centers. Occurrence and biosynthesis Diacetyl arises naturally as a byproduct of fermentation. In some fermentative bacteria, it is formed via the thiamine pyrophosphate-mediated condensation of pyruvate and acetyl CoA. Sour (cultured) cream, cultured buttermilk, and cultured butter are produced by ...
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Mouthfeel
Mouthfeel refers to the physical sensations in the mouth caused by food or drink, making it distinct from taste. It is a fundamental sensory attribute which, along with taste and smell, determines the overall flavor of a food item. Mouthfeel is also sometimes referred to as texture. It is used in many areas related to the testing and evaluating of foodstuffs, such as wine-tasting and food rheology. It is evaluated from initial perception on the palate, to first bite, through chewing to swallowing and aftertaste. In wine-tasting, for example, mouthfeel is usually used with a modifier (big, sweet, tannic, chewy, etc.) to the general sensation of the wine in the mouth. Research indicates texture and mouthfeel can also influence satiety with the effect of viscosity most significant. Mouthfeel is often related to a product's water activity—hard or crisp products having lower water activities and soft products having intermediate to high water activities. Qualities perceived ...
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Apple
An apple is an edible fruit produced by an apple tree (''Malus domestica''). Apple fruit tree, trees are agriculture, cultivated worldwide and are the most widely grown species in the genus ''Malus''. The tree originated in Central Asia, where its wild ancestor, ''Malus sieversii'', is still found today. Apples have been grown for thousands of years in Asia and Europe and were brought to North America by European colonization of the Americas, European colonists. Apples have Religion, religious and mythology, mythological significance in many cultures, including Norse mythology, Norse, Greek mythology, Greek, and Christianity in Europe, European Christian tradition. Apples grown from seed tend to be very different from those of their parents, and the resultant fruit frequently lacks desired characteristics. Generally, apple cultivars are propagated by clonal grafting onto rootstocks. Apple trees grown without rootstocks tend to be larger and much slower to fruit after plantin ...
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Body (wine)
The use of wine tasting descriptors allows the taster to qualitatively relate the aromas and flavors that the taster experiences and can be used in assessing the overall quality of wine. Wine writers differentiate wine tasters from casual enthusiasts; tasters attempt to give an objective description of the wine's taste (often taking a systematic approach to tasting), casual enthusiasts appreciate wine but pause their examination sooner than tasters. The primary source of a person's ability to taste wine is derived from their olfactory senses. A taster's own personal experiences play a significant role in conceptualizing what they are tasting and attaching a description to that perception. The individual nature of tasting means that descriptors may be perceived differently among various tasters. The following is an incomplete list of wine tasting descriptors and a common meaning of the terms. These terms and usage are from Karen MacNeil's 2001 edition of ''The Wine Bible'' u ...
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Flavor (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, Taste#Bitterness, bitterness, saltiness, sweetness and Umami, 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 wine terms, 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 reaction ...
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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 ...
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