Flor (Spanish and Portuguese for ''flower'') in

winemaking Winemaking, wine-making, or vinification is the production of wine, starting with the selection of the fruit, its Ethanol fermentation, fermentation into alcohol, and the bottling of the finished liquid. The history of wine-making stretches over ...

, is a film of

yeast Yeasts are eukaryotic, single-celled microorganisms classified as members of the fungus kingdom (biology), kingdom. The first yeast originated hundreds of millions of years ago, and at least 1,500 species are currently recognized. They are est ...

on the surface of

wine Wine is an alcoholic drink made from Fermentation in winemaking, fermented fruit. Yeast in winemaking, Yeast consumes the sugar in the fruit and converts it to ethanol and carbon dioxide, releasing heat in the process. Wine is most often made f ...

, important in the manufacture of some styles of

sherry Sherry ( ) is a fortified wine produced from white grapes grown around the city of Jerez de la Frontera in Andalusia, Spain. Sherry is a drink produced in a variety of styles made primarily from the Palomino grape, ranging from light versio ...

. The flor is formed naturally under certain winemaking conditions, from indigenous yeasts found in the region of

Andalucía Andalusia ( , ; , ) is the southernmost autonomous communities of Spain, autonomous community in Peninsular Spain, located in the south of the Iberian Peninsula, in southwestern Europe. It is the most populous and the second-largest autonomou ...

in southern

Spain Spain, or the Kingdom of Spain, is a country in Southern Europe, Southern and Western Europe with territories in North Africa. Featuring the Punta de Tarifa, southernmost point of continental Europe, it is the largest country in Southern Eur ...

. Normally in winemaking, it is essential to keep young wines away from exposure to air by sealing them in airtight barrels, to avoid contamination by

bacteria Bacteria (; : bacterium) are ubiquitous, mostly free-living organisms often consisting of one Cell (biology), biological cell. They constitute a large domain (biology), domain of Prokaryote, prokaryotic microorganisms. Typically a few micr ...

and yeasts that tend to spoil it. However, in the manufacture of sherries, the slightly porous oak barrels are deliberately filled only about five-sixths full with the young wine, leaving "the space of two fists" empty to allow the flor yeast to take form and the

bung A stopper, bung, or cork is a cylindrical or conical closure used to seal a container, such as a bottle, tube, or barrel. Description Unlike a lid or bottle cap, which encloses a container from the outside without displacing the inner v ...

is not completely sealed. The flor favors cooler climates and higher humidity, so the sherries produced in the coastal

Sanlúcar de Barrameda Sanlúcar may refer to: * Sanlúcar de Barrameda, a city in the Province of Cádiz, Spain * Sanlúcar de Guadiana, a village in the Province of Huelva, Spain * Sanlúcar la Mayor, a city in the Province of Seville, Spain *Sanlúcar de Albaida, forme ...

and

El Puerto de Santa María El Puerto de Santa María (), locally known as El Puerto and historically in English as Port Saint Mary, is a Municipalities in Spain, municipality of Spain located on the banks of the Guadalete River in the province of Cádiz, Andalusia. , the c ...

have a thicker cap of flor than those produced inland in

Jerez Jerez de la Frontera () or simply Jerez, also cited in old English-language sources as , is a city and municipality in the province of Cádiz in the autonomous community of Andalusia, Spain. Located in southwestern Iberia, it lies on the Campi� ...

. The yeast gives the resulting sherry its distinctive fresh taste, with residual flavors of fresh bread. Depending on the development of the wine, it may be aged entirely under the veil of flor to produce a

fino In computer science, FINO is a humorous scheduling algorithm. It is an acronym for ''first in, never out'' as opposed to traditional ''first in, first out'' (FIFO) and ''last in, first out'' (LIFO) algorithms. A similar acronym is "FISH", for ...

or manzanilla sherry, or it may be fortified to limit the growth of flor and undergo oxidative aging to produce an

amontillado Amontillado () is a variety of sherry wine characterised by being darker than fino sherry, but lighter than oloroso sherry. Amontillado wine is named after the Montilla municipality, in Andalusia, Spain, where the style of sherry originated in th ...

oloroso Oloroso ("scented" in English language, English) is a variety of fortified wine (sherry) made in Jerez de la Frontera, Jerez and Montilla-Moriles and produced by oxidative Aging of wine, aging. It is normally darker than Amontillado. Oloroso is us ...

sherry. During the

fermentation Fermentation is a type of anaerobic metabolism which harnesses the redox potential of the reactants to make adenosine triphosphate (ATP) and organic end products. Organic molecules, such as glucose or other sugars, are catabolized and reduce ...

phase of sherry production, the flor yeast works anaerobically, converting

sugar Sugar is the generic name for sweet-tasting, soluble carbohydrates, many of which are used in food. Simple sugars, also called monosaccharides, include glucose Glucose is a sugar with the Chemical formula#Molecular formula, molecul ...

into ethanol. When all the sugar has been consumed, the physiology of the yeast changes to where it begins an

aerobic Aerobic means "requiring air," in which "air" usually means oxygen. Aerobic may also refer to * Aerobic exercise, prolonged exercise of moderate intensity * Aerobics, a form of aerobic exercise * Aerobic respiration, the aerobic process of cellu ...

process of breaking down and converting the

acids An acid is a molecule or ion capable of either donating a proton (i.e. hydrogen cation, H+), known as a Brønsted–Lowry acid, or forming a covalent bond with an electron pair, known as a Lewis acid. The first category of acids are the ...

into other compounds such as

acetaldehyde Acetaldehyde (IUPAC systematic name ethanal) is an organic compound, organic chemical compound with the chemical formula, formula , sometimes abbreviated as . It is a colorless liquid or gas, boiling near room temperature. It is one of the most ...

. A waxy coating appears on the cells' exterior, causing the yeast to float to the surface and form a protective "blanket" thick enough to shield the wine from

oxygen Oxygen is a chemical element; it has chemical symbol, symbol O and atomic number 8. It is a member of the chalcogen group (periodic table), group in the periodic table, a highly reactivity (chemistry), reactive nonmetal (chemistry), non ...

. This process drastically lowers the acidity of the wine and makes sherry one of the most aldehydic wines in the world. Studies have shown that for the flor to thrive, the wine must stay in a narrow alcohol range of 14.5% to 16%

ABV Alcohol by volume (abbreviated as alc/vol or ABV) is a common measure of the amount of alcohol contained in a given alcoholic beverage. It is defined as the volume the ethanol in the liquid would take if separated from the rest of the solution, ...

. Below 14.5% the yeast will not form its protective cap, and so the wine will

oxidize Redox ( , , reduction–oxidation or oxidation–reduction) is a type of chemical reaction in which the oxidation states of the reactants change. Oxidation is the loss of electrons or an increase in the oxidation state, while reduction is ...

to the point of becoming

vinegar Vinegar () is an aqueous solution of diluted acetic acid and trace compounds that may include flavorings. Vinegar typically contains from 5% to 18% acetic acid by volume. Usually, the acetic acid is produced by a double fermentation, converting ...

. Above 16% the flor cannot survive, and so the wine essentially becomes an

.Robinson, J. (ed). ''The Oxford Companion to Wine'', Third Edition, Oxford University Press, 2006, pp 664-665.

Other regions

A film of yeast similar to flor is also used in the production of

vin jaune is a special and characteristic type of white wine made in the Jura (wine), Jura region in eastern France. It is similar to dry fino Sherry and gets its character from being matured in a barrel under a film of yeast (wine), yeast, known as the ...

in the

Jura wine Jura wine is French wine produced in the Jura '' département''. Located between Burgundy and Switzerland, this cool climate wine region produces wines with some similarity to Burgundy and Swiss wine. Jura wines are distinctive and unusual wi ...

region in eastern

France France, officially the French Republic, is a country located primarily in Western Europe. Overseas France, Its overseas regions and territories include French Guiana in South America, Saint Pierre and Miquelon in the Atlantic Ocean#North Atlan ...

. The French term used for this yeast film is ''voile'', meaning "

veil A veil is an article of clothing or hanging cloth that is intended to cover some part of the human head, head or face, or an object of some significance. Veiling has a long history in European, Asian, and African societies. The practice has be ...

". A similar yeast to flor is used in the production of ''Szamorodni szaraz'' in the

Tokaj Tokaj () is a historical town in Borsod-Abaúj-Zemplén county, Northern Hungary, 54 kilometers from county capital Miskolc. It is the centre of the Tokaj-Hegyalja wine district where Tokaji wine is produced. History The wine-growing area ...

wine region in northeastern

Hungary Hungary is a landlocked country in Central Europe. Spanning much of the Pannonian Basin, Carpathian Basin, it is bordered by Slovakia to the north, Ukraine to the northeast, Romania to the east and southeast, Serbia to the south, Croatia and ...

and southeastern

Slovakia Slovakia, officially the Slovak Republic, is a landlocked country in Central Europe. It is bordered by Poland to the north, Ukraine to the east, Hungary to the south, Austria to the west, and the Czech Republic to the northwest. Slovakia's m ...

. The Hungarian name for this yeast is ''hártya'' which means ''film''. Natural yeast film was traditionally used in

Gose Gose () is a warm fermented beer that is usually brewed with at least 50% of the grain bill being malted wheat (with the rest being malted barley such as Pilsner malt), fruit syrups - such as lemon and coriander - and salt - either added or a ...

beer to seal bottles, instead of caps or corks. Flor is also present in

Vernaccia di Oristano Vernaccia di Oristano is a white Italian wine grape variety grown on the island of Sardinia which makes a wide range of wine styles for the ''Denominazione di origine controllata'' (DOC) of ''Vernaccia di Oristano'' based in the province of Oristan ...

D.O.C. a wine from the italian region of

Sardinia Sardinia ( ; ; ) is the Mediterranean islands#By area, second-largest island in the Mediterranean Sea, after Sicily, and one of the Regions of Italy, twenty regions of Italy. It is located west of the Italian Peninsula, north of Tunisia an ...

and Malvasia di Bosa.

References

{{reflist

External links

Flor, the mystery of sherry
Oenology

Other regions

See also

References

External links