Wines chemical analysis

Rudnitskaya, A., Schmidtke, b. M., Delgadillo, b, begin. A., and ScoUary, G. (2009b). Study of the influence of micro-oxygenation and oak chip maceration on wine composition using an electronic tongue and chemical analysis. Anal. Chim. Acta 642(1-2), 235-245. 

Among Pasteur s many contributions to the wine industry were several simple methods of wine analysis, and his research has had a permanent influence on the wine industry. As a well-trained chemist he was certain that chemical analysis would reveal the nature of the process of alcoholic fermentation and the type and degree of spoilage related to it. In both cases he was correct. 

Constant supervision of wine tanks Prompt and current chemical analysis Organoleptic analysis before and after all wine transfers Sanitation of tanks, hoses, equipment, and pipelines on a rigid schedule Use of N2 and CO2 for oxygen control in bulk wine, in pipelines and in tanks... 

Chemical Analysis. It is suggested that a set procedure be established for running specific analyses according to a specific timetable. For example, a visual and taste inspection of all wines every two weeks (two months for wines in barrels), malic and lactic acid analyses at weekly intervals during the malo-lactic secondary fermentation, and S02 and color analyses of white wines at least every two weeks until the wine is bottled. Basic analyses to monitor are V.A., S02, alcohol, pH, and T.A. 

Hand, P., Ewart, A., and Sitters, J. 1993. Techniques for Chemical Analysis and Stability Tests of Grape Juice and Wine, pp. 22-25. Patrick Hand Wine Promotions, Campbelltown, Australia. 

The quantity of wine for chemical analysis should be at least four bottles of about a litre each. Transparent bottles should be used and they should be rinsed first with water and then with the wine so that no trace of any substance previously present can remain. The bottles should be filled, carefully stoppered with new corks of good quality and provided with sealing-wax seals and with a label giving all the particulars necessary for the identification of the sample. Further, on a special sheet are given the name and address of the holder of the wine, the capacity of the casks or other vessels from which the sample is drawn and the extent to which they are filled, any production of scum (so-called " fleurs de vin ) being noted and, if possible, the type, place of origin and year of production of the wine itself. 

On sensory examination of wines, Lachman was a master. He abhorred still wines of excess carbon dioxide. He writes of first, second, and third tastes. (But some of these are surely odors, not tastes.) Blending is considered the most difficult branch of the handling of wines. It should, he says, be assisted by chemical analysis. The judge must be in condition. He should be able to detect any blemish, and tell whether a wine has been corrected by use of lime, chalk, or salt. This tells us a good deal about the poor quality of wines of the period, as does Bioletti s letter (12). 

The published literature on the effects of microbial activities on wine chemical composition is now considerable. Understanding the significance of wine chemistry is, however, heavily dependent on complex analytical strategies which combine extensive chemical characterization and sensory descriptive analysis. However, sensory analysis is extremely resource-intense, requiring many hours of panelists time. This prevents widespread application of these powerful analytical tools. Advanced statistical techniques have been developed that are closing the gap between chemical and sensory techniques. Such techniques allow the development of models, which should ultimately provide a sensory description based on chemical data. For example, Smyth et al. (2005) have developed reasonable models which can reveal the most likely compounds that relate to particular attributes that characterise the overall sensory profile of a wine. For wines such as Riesling and Chardonnay, the importance of several yeast volatile compounds has been indicated. Such information will allow yeast studies to target key compounds better rather than just those that are convenient to measure. 

Cork taint is a musty/moldy off-odor in wine. It is related to the cork stopper, a wine botde closure made from the bark of the cork oak (Quercus suher). In a correlation between sensory evaluation and chemical analysis, 2,4,6-trichloroanisole (TCA) has b n identified as a major impact component. In sensitivity tests of a group of trained wine judges, a geometric mean of the minimum detectable concentrations of TCA has been determined at 4.6 ng/L. 

Similar analyses are now common in the quality control procedures of many consumer products, such as beer and wine, coffee, fruit juice, and infant formula, where consistency is demanded even though the quality of the raw starting materials may vary with source and season. This is chemical analysis at its best, and the above example is emphasized here because it clearly illustrates this type of approach, which in general combines precise measurements with sophisticated numerical analysis to produce practical results. 

The chemical analysis showed that polymerization and color stability seemed to be favored in small and new barrels. The results of the sensory analysis showed that the origin of the wood did not lead to important sensorial differences and that wines held in 500 and 1000 L barrels had a significantly lower score, wines from 220 liter barrels being, in general, preferred. 

Most of these names correspond to real differences. Names taken from regions, such as Rhine wine or Sauteme, represent large differences in character easily distinguishable by taste and usually by chemical analysis. Names representing vineyards or vintage years represent differences of quality, which may be equally marked to the practiced taster, but are difficult to indicate by chemical means. 

Park, S. K. Noble, A. C. In Beer and Wine Production Analysis, Characterisation and Technological Advances Gump, B., Ed. ACS Symposium Series No. 536 American Chemical Society Washington DC, 1993 pp 98-109. 

In addition to tartaric acid another compound named paratartaric acid was found in wine sediments. Chemical analysis showed this compound to have the same composition as tartaric acid, so most scientists assumed the two compounds were identical. Strangely enough, however, paratartaric acid did not rotate plane-polarized fight. Pasteur would not accept the idea that such an experimental result could be an accident or unimportant. He guessed that even though the two compounds had the same chemical composition, they must somehow have different structures—and he set out to find evidence to prove his hypothesis. 

Gump BH and Pruett DJ (eds.) (1993) Beer and Wine Production Analysis, Characterization and Technological Advances (ACS Symposium Series). American Chemical Society. 

Dowhanick, T.M. and I. Russel. 1993. Advances in detection and identification methods applicable to the brewing industry. Beer and Wine Production. Analysis, Characterization, and Technological Advances. B.H. Gump (ed.). Washington, DC American Chemical Society, pp. 13-32. 

Chemical analysis may help determine that the winemaker or brewer has adhered to certain regulations for example, no more than x% of a given compound should be present in the finished wine or beer. Many regulations actually specify the maximum level of additives or processing aids permitted in the finished product. Other regulations define winemak-... 

Table 8.4. Chemical analysis of Chardonnay wines inoculated with O. oeni strains EQ-54 or WS-8 before (day 0) or after (day 22) completion of alcoholic fermentations.

Muller, C.J., K.C. Fugelsang, and V.L. Wahlstrom. 1993. Capture and use of volatile flavor constituents emitted during wine fermentations. In Beer and Wine Production Analysis, Characterization and Technological Advances. B.H. Gump (Ed.), pp. 219-234. American Chemical Society, Washington, DC. 

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