Flor sherry

Sotolon (4,5-dimethyl-3-hydroxy-2(5H)-furanone) and solerone (4-acetyl- y-butirrolactone) were claimed to be responsible for some aroma characteristic of flor sherries wines. These compounds are present only as traces, and are chemically unstable. A system of two gas chromatographs coupled with a four-port switching valve was used to quantitate these components without previous fractionation. The first chromatograph was equipped with an on-column injector, in order to avoid thermal degradation of sotolon in the heated injector, a DB-5 column and an FID. The second chromatograph was equipped with an on-column injector, a DB-1701 column and an FID. The method allowed quantification of solerone and sotolon at concentrations as low as a few ppb (29). 

CeHgOs, Mr 128.13, was found in, e.g., fenugreek, coffee, sake, and flor-sherry. Its aroma characteristic changes from caramel-like at low concentrations to currylike at high concentrations. A method described for its preparation comprises condensation of ethyl propionate with diethyl oxalate and reaction of the intermediately formed diethyl oxalylpropionate with acetaldehyde. Acidic decarboxylation of the ethyl 4,5-dimethyl-2,3-dioxodihydrofuran-4-carboxylate gives the title compound [199]. 

Flor sherry aldehydes Unknown Unknown Flor yeast... 

The Spanish sherry type of film yeasts tolerate high alcohol concentrations (up to 16 percent) and cause compositional and taste changes which are considered to be serious defects in nearly all wines except Spanish-type flor sherries. The most obvious compositional changes in... 

Flor sherry can be made by the skillful and patient home winegrower although its production probably should not be attempted until... 

Growth of film-forming yeasts is inhibited by ethyl alcohol concentrations higher than about 16 vol %. Fortunately, most of the bacteria and undesirable yeasts which will spoil wines when oxygen is available and which could be a great problem in the production of film wines are inhibited or killed by alcohol levels above 14%. The flor sherry producer thus has a range of about l%-2% ethyl alcohol content in his wines within which it is reasonable to expect film sherry rather than vinegar to result. 

B. Martin and P. Etievant, Quantitative determination of solerone and sotolon in flor sherries by two dimensional capillary GC , 7. High Resolut. Chromatogr. 14 133-135 (1991). 

Charpentier, C., Dos Santos, A. M., and Feuillat, M. (2004). Release of macromolecules by Saccharomyces cerevisiae during aging of flor Sherry wine "vin jaune". Int. ]. Food Microbiol. 96, 253-262. 

Ough, C. S. and Amerine, M. A. (1972). Further studies with submerged flor sherry. Am. ]. Enol. Vitic. 23, 128-131. 

Several botrytized wine specialties, other than Aszu, are also matured in the Tokaj cellars. Traditionally, these were exposed to the air for a short period. Today, this is a characteristic only of dry Szamorodni. During this phase a Saccharomyces film develops spontaneously on the wine s surface. This donates a flor sherry-like character to dry Szamorodni wines (Alkonyi, 2000 Magyar, 2010). The similarity involves only the flor character, since Tokaji Szamorodni never contains added alcohol. Moreover, its acidity and sugar-free extract content is very high and botrytis notes are present in the taste. 

Williams, P. J. and Strauss, C. R. (1978). Studies of volatile components in the dichloromethane extract of Australian flor sherries. The identification of the isomeric ethylideneglycerols. J. Inst. Brew. 84, 144-147. 

The concept and technique of submerged-culture fermentations to accelerate what were originally surface reactions were first used extensively in the pharmaceutical industry. It was apparent to enological researchers in several countries that the same principles could be applied to production of flor sherry. 

One of the California pioneers urging flor sherry production was Cruess (4). On his visits to Spain, Cruess was impressed with the range of types and qualities of Spanish sherries. He felt that the quality of California sherries... 

Fornachon (5) in Australia found that a yeast suspension aerated and agitated in an alcoholic solution produced aldehyde. He reported his extensive research on flor sherry production to the Australian Wine Board (6). 

The combination of oxygen and flor yeast in a suitable shermat results in yeast growth and production of acetaldehyde. The wine passes through many taste and aroma phases during this process. The process is very flexible and can be used to produce anything from a pleasantly aromatic wine at 200 mg/L aldehyde to a strongly flavored flor sherry at 700 mg/L aldehyde to an intensely flavored flor with a long aftertaste at 1000 mg/L aldehyde. 

Webb et al. (14) reported on a comparison of aromas of flor sherry, baked sherry, and submerged-culture sherry. The same compounds were found in all three types, but baked sherry alone contained 2-furaldehyde. 

In conclusion, flor sherry is being produced successfully in California on a commercial scale by the submerged-culture process. 

Cruess, W. V. Investigations of the Flor Sherry Process, Calif. Agric. Exp. 

DeSoto, R.T. Commercial Production of Flor Sherry by the Submerged Cul-... 

Farafontof, A. Studies to Determine the Feasibility of Flor Sherry Production... 

Wurz, R. E. M., Kepner, R. E., Webb, A. D. (1988) The biosynthesis of certain gamma-lactones from glutamic acid by film yeast activity on the surface of Flor Sherry. American Journal of... 

Dubois P., Rigaud J. and Dekimpe J. (1976) Identification of 4,5-dimethyl tetrahydrofuran-2,3-dione in French flor sherry wine. Lebensm. Wiss. Technol. 9, 366-8. 

Martin B., Etievant P. and Henry R.N. (1990) The chemistry of sotolon a key parameter for the study of a key component of flor sherry wines. Weurman 6th Flav. Res. Symp., Flavour Science and Technology, Geneva (Switzerland), 2-4.5.1990, Bessiere Y. Thomas A.F. Eds, John Wiley Sons, Chichester. 53-6. 

An estimation of the importance of Sotolon in establishing the character and persistence of aroma for flor sherry has already been established (12). Nevertheless, in order to gather more information concerning the impact of Sotolon on the typical aroma associated by the consumer with the age of Port wine, sensory analyses needed to be carried out. 

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