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 constitut ...

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

Andalucía Andalusia (, ; es, Andalucía ) is the southernmost Autonomous communities of Spain, autonomous community in Peninsular Spain. It is the most populous and the second-largest autonomous community in the country. It is officially recognised as a ...

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 biological cell. They constitute a large domain of prokaryotic microorganisms. Typically a few micrometres in length, bacteria were among ...

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 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 oppos ...

and

El Puerto de Santa María EL, El or el may refer to: Religion * El (deity), a Semitic word for "God" People * EL (rapper) (born 1983), stage name of Elorm Adablah, a Ghanaian rapper and sound engineer * El DeBarge, music artist * El Franco Lee (1949–2016), American po ...

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 ...

. 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 Fino ("refined" in Spanish) is the driest and palest of the traditional varieties of sherry and Montilla-Moriles fortified wine. They are consumed comparatively young and, unlike the sweeter varieties, should be consumed soon after the bottle ...

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 ...

or oloroso sherry. During the

fermentation Fermentation is a metabolic process that produces chemical changes in organic substrates through the action of enzymes. In biochemistry, it is narrowly defined as the extraction of energy from carbohydrates in the absence of oxygen. In food ...

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, fructose, and galactose. Compound sugars, also called disaccharides or double ...

into ethanol. When all the sugar has been consumed, the physiology of the yeast changes to where it begins an aerobic process of breaking down and converting the acids into other compounds such as

acetaldehyde Acetaldehyde (IUPAC systematic name ethanal) is an organic chemical compound with the formula CH3 CHO, sometimes abbreviated by chemists as MeCHO (Me = methyl). It is a colorless liquid or gas, boiling near room temperature. It is one of the mos ...

. 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. 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. Below 14.5% the yeast will not form its protective cap, and so the wine will oxidize to the point of becoming vinegar. Above 16% the flor cannot survive, and so the wine essentially becomes an oloroso.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 in the Jura wine region in eastern France. The French term used for this yeast film is ''voile'', meaning " veil". A similar yeast to flor is used in the production of ''Szamorodni szaraz'' in the Tokaj wine region in northeastern Hungary. The Hungarian name for this yeast is ''hártya'' which means ''film''. Natural yeast film was traditionally used in Gose beer to seal bottles, instead of caps or corks. Flor is also present in some Vernaccia di Oristano D.O.C. a wine from the italian region of Sardinia.

References

{{reflist

External links

Flor, the mystery of sherry
Oenology

Other regions

See also

References

External links