Chalk is a soft, porous, sedimentary carbonate rock, a form of limestone composed of the mineral calcite. Calcite is an ionic salt called calcium carbonate or CaCO3, it forms under reasonably deep marine conditions from the gradual accumulation of minute calcite shells shed from micro-organisms called coccolithophores. Flint is common as bands parallel to the bedding or as nodules embedded in chalk, it is derived from sponge spicules or other siliceous organisms as water is expelled upwards during compaction. Flint is deposited around larger fossils such as Echinoidea which may be silicified. Chalk as seen in Cretaceous deposits of Western Europe is unusual among sedimentary limestones in the thickness of the beds. Most cliffs of chalk have few obvious bedding planes unlike most thick sequences of limestone such as the Carboniferous Limestone or the Jurassic oolitic limestones; this indicates stable conditions over tens of millions of years. Chalk has greater resistance to weathering and slumping than the clays with which it is associated, thus forming tall, steep cliffs where chalk ridges meet the sea.
Chalk hills, known as chalk downland form where bands of chalk reach the surface at an angle, so forming a scarp slope. Because chalk is well jointed it can hold a large volume of ground water, providing a natural reservoir that releases water through dry seasons. Chalk is mined from chalk deposits both above underground. Chalk mining boomed during the Industrial Revolution, due to the need for chalk products such as quicklime and bricks; some abandoned chalk mines remain tourist destinations due to their massive expanse and natural beauty. The Chalk Group is a European stratigraphic unit, it forms the famous White Cliffs of Dover in Kent, England, as well as their counterparts of the Cap Blanc Nez on the other side of the Dover Strait. The Champagne region of France is underlain by chalk deposits, which contain artificial caves used for wine storage; some of the highest chalk cliffs in the world occur at Jasmund National Park in Germany and at Møns Klint in Denmark – both once formed a single island.
Ninety million years ago what is now the chalk downland of Northern Europe was ooze accumulating at the bottom of a great sea. Chalk was one of the earliest rocks made up of microscopic particles to be studied under the microscope, when it was found to be composed entirely of coccoliths, their shells were made of calcite extracted from the rich seawater. As they died, a substantial layer built up over millions of years and, through the weight of overlying sediments became consolidated into rock. Earth movements related to the formation of the Alps raised these former sea-floor deposits above sea level; the chemical composition of chalk is calcium carbonate, with minor amounts of clay. It is formed in the sea by sub-microscopic plankton, which fall to the sea floor and are consolidated and compressed during diagenesis into chalk rock. Most people first encounter the word "chalk" in school where it refers to blackboard chalk, made of mineral chalk, since it crumbles and leaves particles that stick loosely to rough surfaces, allowing it to make writing that can be erased.
Blackboard chalk manufacture now may use mineral chalk, other mineral sources of calcium carbonate, or the mineral gypsum. While gypsum-based blackboard chalk is the lowest cost to produce, thus used in the developing world, calcium-based chalk can be made where the crumbling particles are larger and thus produce less dust, is marketed as "dustless chalk". Colored chalks, pastel chalks, sidewalk chalk, used to draw on sidewalks and driveways, are made of gypsum. Chalk is a source of quicklime by thermal decomposition, or slaked lime following quenching of quicklime with water. In southeast England, deneholes are a notable example of ancient chalk pits; such bell pits may mark the sites of ancient flint mines, where the prime object was to remove flint nodules for stone tool manufacture. The surface remains at Cissbury are one such example, but the most famous is the extensive complex at Grimes Graves in Norfolk. Woodworking joints may be fitted by chalking one of the mating surfaces. A trial fit will leave a chalk mark on the high spots of the corresponding surface.
Chalk transferring to cover the complete surface indicates a good fit. Builder's putty mainly contains chalk as a filler in linseed oil. Chalk may be used for its properties as a base. In agriculture, chalk is used for raising pH in soils with high acidity; the most common forms are CaCO3 and CaO. Small doses of chalk can be used as an antacid. Additionally, the small particles of chalk make it a substance ideal for polishing. For example, toothpaste contains small amounts of chalk, which serves as a mild abrasive. Polishing chalk is chalk prepared with a controlled grain size, for fine polishing of metals. Chalk can be used as fingerprint powder. Several traditional uses of chalk have been replaced by other substances, although the word "chalk" is still applied to the usual replacements. Tailor's chalk is traditionally a hard chalk used to make temporary markings on cloth by tailors, it is now made of talc. Chalk was traditionally used in recreation. In field sports, such as tennis played on grass, powdered chalk was used to mark the boundary lines of the playing field or court.
If a ball hits the line, a cloud of chalk or p
Coulure is a viticultural hazard, the result of metabolic reactions to weather conditions that causes a failure of grapes to develop after flowering. In English the word shatter is sometimes used. Coulure is triggered by periods of cold, rainy weather or high out-of-season temperatures; the condition is most manifested in the spring. It occurs in vines that have little sugar content in their tissue. Flowers are not fertilized, thus the vines falls off. Coulure can cause irregular bunches of grapes which are less compact than normal; these bunches are more sensitive to developing various grape diseases. The yield of a vine with coulure will decrease substantially. Grape varieties with high proclivity to coulure are Grenache, Malbec and Muscat Ottonel. Other causes of coulure may be vineyard conditions and practices, pruning too early or too excessively fertile soils or overuse of fertilizers, improper selection of rootstocks or clones. During the flowering part of the growing season, grapevines need dry conditions with sufficient sunlight and ambient air temperature around 15 °C for pollination to go smoothly.
Less ideal conditions wet, rainy weather, increases the odds that a higher than normal numbers of flowers go unpollinated and coulure to occur. Coulure is a distinct phenomena unrelated to another viticultural hazard, where the flowers are pollinated but the resulting berries develop with seeds and remain small. Like coulure, millerandage is caused by inclement weather during the flowering and fruit set period and cause reduced yields. Coulure is caused by a carbohydrate deficiency in the plant tissues that causes the vine to conserve resources that would otherwise be funneled into the developing grape berries; as carbohydrate levels drop, soon after flowering the stems connected to the berries shrivel as the small grapes fall off. To some extent coulure and the dropping of fruit is a natural and healthy reaction of a vine, self-regulating its resource and the amount of fruit that it produces, but when the situation is exacerbated by certain weather conditions and disruption to photosynthesis, coulure can have a more severe impact on yields that may negatively affect a region's grape supply and thus influence pricing.
When the weather is the primary instigator of coulure, the French term this phenomenon coulure climatique. This describes the cloudy and wet conditions that limit the amount of photosynthetic activity that takes place during the flowering cycle of a grapevine. Limited sunshine means lower sugar levels that can be converted into resources to develop grape berries. Warm temperatures can exacerbate coulure in some grape varieties by promoting cellular respiration and excessive shoot growth that further competes with the berries for the resources derived from carbohydrates. Other contributing factors include excessively fertile vineyard soils, either or enhanced by the use of nitrogen-rich fertilizers, overly vigorous rootstock and severe pruning that too drastically limits the amount of leaf surface needed to sustain photosynthesis. Coulure is not 100% preventable but a vineyard manager can take several precautions to lessen the severity and impact of coulure; some grape varieties are more prone to develop coulure than others, such as Grenache, Malbec and Muscat Ottonel.
A grower can choose to grow clones of those varieties, now available for Merlot and Malbec, that have less susceptibility to developing coulure. In the vineyard, care can be taken to not prune so and insure that there is adequate leaf coverage for photosynthesis. Trimming the tips of developing shoots near the end of the flowering period can lessen the competition for sugar resources between berries and new shoot development. For non-organic viticulture, chemical growth inhibitors can be applied to the vine to limit shoot growth as well. Epicurious.com Professional Friends of Wine
Abbot, meaning father, is an ecclesiastical title given to the male head of a monastery in various traditions, including Christianity. The office may be given as an honorary title to a clergyman, not the head of a monastery; the female equivalent is abbess. The title had its origin in the monasteries of Egypt and Syria, spread through the eastern Mediterranean, soon became accepted in all languages as the designation of the head of a monastery; the word is derived from the Aramaic av meaning "father" or abba, meaning "my father". In the Septuagint, it was written as "abbas". At first it was employed as a respectful title for any monk, but it was soon restricted by canon law to certain priestly superiors. At times it was applied to various priests, e.g. at the court of the Frankish monarchy the Abbas palatinus and Abbas castrensis were chaplains to the Merovingian and Carolingian sovereigns’ court and army respectively. The title abbot came into general use in western monastic orders whose members include priests.
An abbot is the head and chief governor of a community of monks, called in the East hegumen or archimandrite. The English version for a female monastic head is abbess. In Egypt, the first home of monasticism, the jurisdiction of the abbot, or archimandrite, was but loosely defined. Sometimes he ruled over only one community, sometimes over several, each of which had its own abbot as well. Saint John Cassian speaks of an abbot of the Thebaid. By the Rule of St Benedict, until the Cluniac reforms, was the norm in the West, the abbot has jurisdiction over only one community; the rule, as was inevitable, was subject to frequent violations. Monks, as a rule, at the outset was the abbot any exception. For the reception of the sacraments, for other religious offices, the abbot and his monks were commanded to attend the nearest church; this rule proved inconvenient when a monastery was situated in a desert or at a distance from a city, necessity compelled the ordination of some monks. This innovation was not introduced without a struggle, ecclesiastical dignity being regarded as inconsistent with the higher spiritual life, before the close of the 5th century, at least in the East, abbots seem universally to have become deacons, if not priests.
The change spread more in the West, where the office of abbot was filled by laymen till the end of the 7th century. The ecclesiastical leadership exercised by abbots despite their frequent lay status is proved by their attendance and votes at ecclesiastical councils, thus at the first Council of Constantinople, AD 448, 23 archimandrites or abbots sign, with 30 bishops. The second Council of Nicaea, AD 787, recognized the right of abbots to ordain their monks to the inferior orders below the diaconate, a power reserved to bishops. Abbots used to be subject to episcopal jurisdiction, continued so, in fact, in the West till the 11th century; the Code of Justinian expressly subordinates the abbot to episcopal oversight. The first case recorded of the partial exemption of an abbot from episcopal control is that of Faustus, abbot of Lerins, at the council of Arles, AD 456; these exceptions, introduced with a good object, had grown into a widespread evil by the 12th century creating an imperium in imperio, depriving the bishop of all authority over the chief centres of influence in his diocese.
In the 12th century, the abbots of Fulda claimed precedence of the archbishop of Cologne. Abbots more and more assumed episcopal state, in defiance of the prohibition of early councils and the protests of St Bernard and others, adopted the episcopal insignia of mitre, ring and sandals, it has been maintained that the right to wear mitres was sometimes granted by the popes to abbots before the 11th century, but the documents on which this claim is based are not genuine. The first undoubted instance is the bull by which Alexander II in 1063 granted the use of the mitre to Egelsinus, abbot of the monastery of St Augustine at Canterbury; the mitred abbots in England were those of Abingdon, St Alban's, Battle, Bury St Edmunds, St Augustine's Canterbury, Croyland, Glastonbury, Gloucester, St Benet's Hulme, Malmesbury, Ramsey, Selby, Tavistock, Westminster, St Mary's York. Of these the precedence was yielded to the abbot of Glastonbury, until in AD 1154 Adrian IV granted it to the abbot of St Alban's, in which monastery he had been brought up.
Next after the abbot of St Alban's ranked the abbot of Westminster and Ramsey. Elsewhere, the mitred abbots that sat in the Estates of Scotland were of Arbroath, Coupar Angus, Holyrood, Kelso, Kinloss, Paisley, Scone, St Andrews Priory and Sweetheart. To distinguish abbots from bishops, it was ordained that their mitre should be made
In viticulture, the yield is a measure of the amount of grapes or wine, produced per unit surface of vineyard, is therefore a type of crop yield. Two different types of yield measures are used, mass of grapes per vineyard surface, or volume of wine per vineyard surface; the yield is seen as a quality factor, with lower yields associated with wines with more concentrated flavours, the maximum allowed yield is therefore regulated for many wine appellations. In most of Europe, yield is measured in hectoliters per hectare, i.e. by the volume of wine. In most of the New World, yield is measured in tonnes per hectare – i.e. by mass of grapes produced per unit area. Due to differing winemaking procedures for different styles of wine, different properties of different grape varieties, the amount of wine produced from a unit mass of grapes varies, it is therefore not possible to make an exact conversion between these units. Representative figures for the amount of grapes needed for 100 l of wine are 160 kg for white wine, 130 kg for red wine, 140 kg for a mixture of red and white wine.
Thus: for white wine, 100 hl/ha ≈ 16,000 kg/ha = 6.5 tons per acre. 1 ton per acre = 2470 kg/ha ≈ 15 hl/ha for red wine, 100 hl/ha ≈ 13,000 kg/ha = 5.3 tons per acre. 1 ton per acre = 2470 kg/ha ≈ 19 hl/ha for mixed wine, 100 hl/ha ≈ 14,000 kg/ha = 5.7 tons per acre. 1 ton per acre = 2470 kg/ha ≈ 17.5 hl/ha Yields vary between countries and individual vineyards, can be vintage-dependent. Somewhere around 50 hectoliters per hectare, or 3 tons per acre, is a typical representative figure for many countries and regions. While yield is seen as an important quality factor in wine production, views differ on the relative importance of low yields to other aspects of vineyard management. In general, there is consensus that if vines are cropped with a high amount of grape clusters, a poor wine will result because of slow and insufficient ripening of the grapes, due to an unfavorable leaf to fruit ratio; this is a situation that would correspond to yields of, say, 200 hl/ha or more, depending on grape variety and many other factors.
Beyond that, there are differing schools of thought. One school of thought subscribed to in France, claims that great red wine is impossible to produce at yields exceeding 50 hl/ha. Another school of thought claims that a yield of 100 hl/ha is possible to combine with high quality, provided that careful canopy management is used. In general, white wine is seen as less sensitive to high yields, some grape varieties, such as Pinot noir, as sensitive to overcropping. Many examples exist where a vintage-to-vintage variation of yields is in fact positively related with quality, since the low yields can be due to loss of grapes due to adverse conditions such as hail or grey rot. For the Bordeaux vintages of the 1980s, it is recognized that the most abundant harvests gave the best vintages. In both France and Italy, the maximum allowed yields are regulated in wine laws, vary between appellations. In France, the maximum yields are given in the regulations for each appellation d'origine contrôlée; the maximum allowed yield for given AOC in a given vintage is a combination of the base yield of the AOC, as modified by the plafond limité de classement, percentage set for each vintage.
In most vintages, the PLC allows a production around 20 per cent above the base yield
Viola is a genus of flowering plants in the violet family Violaceae. It is the largest genus in the family, containing between 600 species. Most species are found in the temperate Northern Hemisphere; some Viola species are perennial plants, some are annual plants, a few are small shrubs. A large number of species and cultivars are grown in gardens for their ornamental flowers. In horticulture the term pansy is used for those multi-colored, large-flowered cultivars which are raised annually or biennially from seed and used extensively in bedding; the terms viola and violet are reserved for small-flowered annuals or perennials, including the wild species. Viola have heart-shaped, scalloped leaves, though a number have palmate leaves or other shapes; the vast majority of Viola species are herbaceous, a substantial number are acaulescent in habit - meaning they lack any noticeable stems and the foliage and flowers appear to rise from the ground. The simple leaves of plants with either habit are arranged alternately.
Plants always have leaves with stipules that are leaf-like. The flowers of the vast majority of the species are zygomorphic with bilateral symmetry; the flowers are formed from five petals. The shape of the petals and placement defines many species, for example, some species have a "spur" on the end of each petal while most have a spur on the lower petal. Solitary flowers end long stalks with a pair of bracteoles; the flowers have five sepals that persist after blooming, in some species the sepals enlarge after blooming. The flowers have five free stamens with short filaments that are oppressed against the ovary, only the lower two stamens have nectary spurs that are inserted on the lowest petal into the spur or a pouch; the flower styles are thickened near the top and the stigmas are head-like, narrowed or beaked. The flowers have a superior ovary with one cell. Viola are most spring blooming with chasmogamous flowers with well-developed petals pollinated by insects. Many species produce self-pollinated cleistogamous flowers in summer and autumn that do not open and lack petals.
In some species the showy chasmogamous flowers are infertile. After flowering, fruit capsules are produced. On drying, the capsules may eject seeds with considerable force to distances of several meters; the nutlike seeds have straight embryos, flat cotyledons, soft fleshy endosperm, oily. The seeds of some species are dispersed by ants. Flower colors vary in the genus, ranging from violet, through various shades of blue, yellow and cream, whilst some types are bicolored blue and yellow. Flowering is profuse, may last for much of the spring and summer. One quirk of some Viola is the elusive scent of their flowers. See List of Viola species for a more complete list. Note: Neither Saintpaulia nor Erythronium dens-canis are related to the true Viola; the genus includes dog violets, a group of scentless species which are the most common Viola in many areas, sweet violet, many other species whose common name includes the word "violet". Several species are known as pansies, including the yellow pansy of the Pacific coast.
Common blue violet Viola sororia is the state flower of Wisconsin, Rhode Island and New Jersey. Australia is home to a number of Viola species, including Viola hederacea, Viola betonicifolia and Viola banksii, first collected by Joseph Banks and Daniel Solander on the Cook voyage to Botany Bay. One fossil seed of †Viola rimosa has been extracted from borehole samples of the Middle Miocene fresh water deposits in Nowy Sacz Basin, West Carpathians, Poland. Cultivars of Viola cornuta, Viola cucullata, Viola odorata, are grown from seed. Other species grown include Viola labradorica, Viola pedata, Viola rotundifolia; the modern garden pansy is a plant of complex hybrid origin involving at least three species, V. tricolor, V. altaica, V. lutea. The hybrid horned pansy originates from hybridization involving Viola cornuta. In 2005 in the United States, Viola cultivars were one of the top three bedding plant crops and 111 million dollars worth of flats of Viola were produced for the bedding flower market.
Pansies and violas used for bedding are raised from seed, F1 hybrid seed strains have been developed which produce compact plants of reasonably consistent flower coloring and appearance. Bedding plants are discarded after one growing season. There are hundreds of perennial violetta cultivars. Violettas can be distinguished from violas by the lack of ray markings on their petals; the following cultivars, of mixed or uncertain parentage, have gained the Royal Horticultural Society's Award of Garden Merit:-'Aspasia"Clementina"Huntercombe Purple"Moonlight
Black pepper is a flowering vine in the family Piperaceae, cultivated for its fruit, known as a peppercorn, dried and used as a spice and seasoning. When fresh and mature, it is about 5 mm in diameter and dark red, contains a single seed, like all drupes. Peppercorns and the ground pepper derived from them may be described as pepper, or more as black pepper, green pepper, or white pepper. Black pepper is native to present-day Kerala in Southwestern India, is extensively cultivated there and elsewhere in tropical regions. Vietnam is the world's largest producer and exporter of pepper, producing 34% of the world's crop, as of 2013. Ground dried and cooked peppercorns have been used since antiquity, both for flavour and as a traditional medicine. Black pepper is the world's most traded spice, is one of the most common spices added to cuisines around the world, its spiciness is due to the chemical compound piperine, a different kind of spicy from the capsaicin characteristic of chili peppers. It is ubiquitous in the modern world as a seasoning, is paired with salt and available on dining tables in shakers.
The word pepper has roots in the Sanskrit word pippali for long pepper. Ancient Greek and Latin turned pippali into the Greek πέπερι peperi and into the Latin piper, which the Romans used for both black pepper and long pepper, erroneously believing that both came from the same plant. From its Sanskrit roots, today's "pepper" is derived from the Old English pipor and from Latin, the source of Romanian piper, Italian pepe, Dutch peper, German Pfeffer, French poivre, other similar forms. In the 16th century, people began using pepper to mean the unrelated New World chili pepper. People have used pepper in a figurative sense to mean "spirit" or "energy" at least as far back as the 1840s. In the early 20th century, this shortened to "pep". Black pepper is produced from the unripe drupes of the pepper plant; the drupes are cooked in hot water, both to clean them and to prepare them for drying. The heat ruptures cell walls in the pepper; the drupes dry in the sun or by machine for several days, during which the pepper skin around the seed shrinks and darkens into a thin, wrinkled black layer.
Once dry, the spice is called black peppercorn. On some estates, the berries are separated from the stem by hand and sun-dried without the boiling process. Once the peppercorns are dried, pepper spirit and oil can be extracted from the berries by crushing them. Pepper spirit is used in many beauty products. Pepper oil is used as an ayurvedic massage oil and in certain beauty and herbal treatments. White pepper consists of the seed of the ripe fruit of the pepper plant, with the thin darker-coloured skin of the fruit removed; this is accomplished by a process known as retting, where ripe red pepper berries are soaked in water for about a week so the flesh of the peppercorn softens and decomposes. Sometimes alternative processes are used for removing the outer pepper from the seed, including removing the outer layer through mechanical, chemical, or biological methods. Ground white pepper is used in Chinese and Thai cuisine, but in salads, cream sauces, light-coloured sauces, mashed potatoes. However, white pepper has a different flavour from black pepper.
Green pepper, like black pepper, is made from unripe drupes. Dried green peppercorns are treated in a way that retains the green colour, such as with sulphur dioxide, canning, or freeze-drying. Pickled peppercorns green, are unripe drupes preserved in brine or vinegar. Fresh, unpreserved green pepper drupes unknown in the West, are used in some Asian cuisines Thai cuisine, their flavour has been described as "spicy and fresh", with a "bright aroma". They decay if not dried or preserved, making them unsuitable for international shipping. Wild pepper grows in the Western Ghats region of India. Into the 19th century, the forests contained expansive wild pepper vines, as recorded by the Scottish physician Francis Buchanan in his book A journey from Madras through the countries of Mysore and Malabar. However, deforestation resulted in wild pepper growing in more limited forest patches from Goa to Kerala, with the wild source decreasing as the quality and yield of the cultivated variety improved. No successful grafting of commercial pepper on wild pepper has been achieved to date.
Orange pepper or red pepper consists of ripe red pepper drupes preserved in brine and vinegar. Ripe red peppercorns can be dried using the same colour-preserving techniques used to produce green pepper. Pink peppercorns are the fruits of the Peruvian pepper tree, Schinus molle, or its relative, the Brazilian pepper tree, Schinus terebinthifolius, plants from a different family; as they are members of the cashew family, they may cause allergic reactions, including anaphylaxis, for persons with a tree nut allergy. The bark of Drimys winteri is used as a substitute for pepper in cold and temperate regions of Chile and Argentina, where it is found and available. In New Zealand, the seeds of kawakawa, a relative of black pepper, are sometimes used as pepper.
Vitis vinifera, the common grape vine, is a species of Vitis, native to the Mediterranean region, central Europe, southwestern Asia, from Morocco and Portugal north to southern Germany and east to northern Iran. There are between 5,000 and 10,000 varieties of Vitis vinifera grapes though only a few are of commercial significance for wine and table grape production, it is a liana growing to 32 m with flaky bark. The leaves are 5 -- 20 cm long and broad; the fruit is a berry, known as a grape. The species occurs in humid forests and streamsides; the wild grape is classified as V. vinifera subsp. Sylvestris, with V. vinifera subsp. Vinifera restricted to cultivated forms. Domesticated vines subsp.. Sylvestris is dioecious and pollination is required for fruit to develop; the grape is eaten processed to make wine or juice, or dried to produce raisins. Cultivars of Vitis vinifera form the basis of the majority of wines produced around the world. All of the familiar wine varieties belong to Vitis vinifera, cultivated on every continent except for Antarctica, in all the major wine regions of the world.
Wild grapes were harvested by early farmers. For thousands of years, the fruit has been harvested for both nutritional value. Changes in pip shape and distribution point to domestication occurring about 3500–3000 BC, in southwest Asia, South Caucasus, or the Western Black Sea shore region; the earliest evidence of domesticated grapes has been found at Gadachrili Gora, near the village of Imiri, Marneuli Municipality, in southeastern Republic of Georgia. Grape pips dating back to the V-IV millennia B. C. were found in Shulaveri. C. were found in Khizanaant Gora, all in the Republic of Georgia. Cultivation of the domesticated grape spread to other parts of the Old World in pre-historic or early historic times; the first written accounts of grapes and wine can be found in the Epic of Gilgamesh, an ancient Sumerian text from the third millennium BC. There are numerous hieroglyphic references from ancient Egypt, according to which wine was reserved for priests, state functionaries and the pharaoh. Hesiod in his Works and Days gives detailed descriptions of grape harvests and wine making techniques, there are many references in Homer.
Greek colonists introduced these practices in their colonies in southern Italy, known as Enotria due to its propitious climate. The Etruscans improved wine making techniques and developed an export trade beyond the Mediterranean basin; the ancient Romans further developed the techniques learnt from the Etruscans, as shown by numerous works of literature containing information, still valid today: De Agri Cultura by Cato the Elder, De re rustica by Marcus Terentius Varro, the Georgics by Virgil and De re rustica by Columella. During the 3rd and 4th centuries AD, the long crisis of the Roman Empire generated instability in the countryside which led to a reduction of viticulture in general, sustained only close to towns and cities and along coastlines. Between the 5th and 10th centuries, viticulture was sustained exclusively by the different religious orders in monasteries; the Benedictines and others extended the grape growing limit northwards and planted new vineyards at higher altitudes than was customary before.
Apart from ‘ecclesiastical’ viticulture, there developed in France, a ‘noble’ viticulture, practiced by the aristocracy as a symbol of prestige. Grape growing was a significant economic activity in the Middle east up to the 7th century, when the expansion of Islam caused it to decline. Between the Low Middle Ages and the Renaissance, viticulture began to flourish again. Demographic pressure, population concentration in towns and cities, the increased spending power of artisans and merchants gave rise to increased investment in viticulture, which became economically feasible once more. Much was written during the Renaissance on grape growing and wine production, favouring a more scientific approach; this literature can be considered the origin of modern ampelography. Grapes followed European colonies around the world, coming to North America around the 17th century, to Africa, South America and Australia. In North America it formed hybrids with native species from the genus Vitis. North American rootstocks became used to graft V. vinifera cultivars so as to withstand the presence of phylloxera.
V. Vinifera accounts for the majority of world wine production. In Europe, Vitis vinifera is concentrated in the southern regions.