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

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 ...

, is a film of

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

on the surface of

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 m ...

, important in the manufacture of some styles of

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 versi ...

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

Spain , image_flag = Bandera de España.svg , image_coat = Escudo de España (mazonado).svg , national_motto = ''Plus ultra'' (Latin)(English: "Further Beyond") , national_anthem = (English: "Royal March") , i ...

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

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

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

Sanlúcar de Barrameda Sanlúcar de Barrameda (), or simply Sanlúcar, is a city in the northwest of Cádiz province, part of the autonomous community of Andalucía in southern Spain. Sanlúcar is located on the left bank at the mouth of the Guadalquivir River opposit ...

and El Puerto de Santa María have a thicker cap of flor than those produced inland in

Jerez Jerez de la Frontera (), or simply Jerez (), is a Spanish city and municipality in the province of Cádiz in the autonomous community of Andalusia, in southwestern Spain, located midway between the Atlantic Ocean and the Cádiz Mountains. , the c ...

. 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 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 but lighter than oloroso. It is named after the Montilla region of Spain, where the style originated in the 18th century, although the name "Amontillado" is somet ...

oloroso Oloroso ("scented" in Spanish) is a variety of fortified wine (sherry) made in Jerez and Montilla-Moriles and produced by oxidative aging. It is normally darker than Amontillado. Oloroso is usually dark and nutty. Unlike the fino and Amontillad ...

sherry. During the fermentation phase of sherry production, the flor yeast works anaerobically, converting sugar 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 cel ...

process of breaking down and converting the

acids In computer science, ACID ( atomicity, consistency, isolation, durability) is a set of properties of database transactions intended to guarantee data validity despite errors, power failures, and other mishaps. In the context of databases, a ...

into other compounds such as acetaldehyde. 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 the chemical element with the symbol O and atomic number 8. It is a member of the chalcogen group in the periodic table, a highly reactive nonmetal, and an oxidizing agent that readily forms oxides with most elements as ...

. 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 ABV, abv, or alc/vol) is a standard measure of how much alcohol (ethanol) is contained in a given volume of an alcoholic beverage (expressed as a volume percent). It is defined as the number of millilitres (mL) o ...

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

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

to the point of becoming

vinegar Vinegar is an aqueous solution of acetic acid and trace compounds that may include flavorings. Vinegar typically contains 5–8% acetic acid by volume. Usually, the acetic acid is produced by a double fermentation, converting simple sugars to eth ...

. 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 ''Vin jaune'' ( French for "yellow wine") is a special and characteristic type of white wine made in the 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 y ...

in the

Jura wine Jura may refer to: Places * Jura, Scotland, island of the Inner Hebrides off Great Britain *Jūra, river in Lithuania Mountain ranges * Jura Mountains, on the French–Swiss–German border *Franconian Jura, south-central Germany *Swabian Jura, ...

region in eastern

France France (), officially the French Republic ( ), is a country primarily located in Western Europe. It also comprises of overseas regions and territories in the Americas and the Atlantic, Pacific and Indian Oceans. Its metropolitan area ...

. 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 head or face, or an object of some significance. Veiling has a long history in European, Asian, and African societies. The practice has been prominent ...

". 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 w ...

wine region in northeastern

Hungary Hungary ( hu, Magyarország ) is a landlocked country in Central Europe. Spanning 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 ...

. 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 originated in Goslar, Germany. It is usually brewed with at least 50% of the grain bill being malted wheat. Dominant flavours in gose include a lemon sourness, a herbal characteristic, and a strong salti ...

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

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 ( ; it, Sardegna, label=Italian, Corsican and Tabarchino ; sc, Sardigna , sdc, Sardhigna; french: Sardaigne; sdn, Saldigna; ca, Sardenya, label=Algherese and Catalan) is the second-largest island in the Mediterranean Sea, after ...

References

{{reflist

External links

Flor, the mystery of sherry
Oenology

Other regions

See also

References

External links