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The Council Regulation (EC) no. 1493/1999 of 17 May 1999 on the common organisation of the market in wine (Abl. L 179 dated 14/7/1999) and the GMO Wine 2000 (Annex VII A) stipulates that the labels of wine bottles have to indicate, among others, information on the sales designation of the product, the nominal volume and the alcoholic strength. The latter must not differ by more than 0.5% vol. from the alcoholic strength as established by analysis. Only when quality wines are stored in bottles for more than three years, the accepted tolerance limits are +/- 0.8% vol. The presented investigation results show that deviations have to be taken into account which may be highly relevant for forensic practice.

In the course of our investigations we tried to find a method for the bouquet qualification of wines by gas chromatography. For this purpose, instead of aroma research studies requiring complex equipment and laboursome precise laboratory work, we developed a method for head space analysis functioning with simple experimental instruments and being sufficiently fast for serial routine work. By the method developed, the head space of a great number of samples taken from 7 different wine-types have been successfully examined. Errors of measurement were checked by standard deviation analysis and the values obtained (3,23%) were found satisfactory. According to the above, our head space analysis may provide a satisfactory basis for elaborating a method for the instrumental bouquet qualification of wines.

In a previous paper we described a method by which routine head-space analysis of wines can be performed with sufficiently accurate results by means of gas chromatography. From the results thus obtained, with application of organoleptic data, chemical and classical analytical parameters of aromatic changes during seasoning and storing wines as well as mathematical-statistical data of the method elaborated, a mathematical relationship has been derived between gas chromatographic peak areas characteristic of different aroma components and the bouquet of wine. Reliability of the method has been verified by the fact that, in spite of the small number of samples, the bouquet of seven different types of wine could be discriminated in 95,45% probalility. The method allows arbitrary choice in the number of samples and in the degree of reliability required, in investigating the quality of a wine. For this purpose, another mathematical relationship has been set up to provide criteria for the distinction of the quality of bouquets. By this method, the bouquet of various types of wines or within an identical type, the bouquet of different vintages and/or bottlings can be determined.

6, 12 and 18 months after bottling, 1 sample of the primary wine, 2 samples of tank-fermented sparkling wines (taken at different production phases, i.e., during and after the second fermentation) and 3 samples of bottle-fermented raw champagne were analysed for aroma and flavour components. The samples were extracted with ether-pentane (2:1) and analysed by gas chromatography. 21 components were detected, 9 of which were identified (isopropanol, n-propanol, isobutanol, n-butanol, isopentanol, heptanal, n-hexanal, n-heptanol, isooctanol). There were marked qualitative and quantitative differences in composition between the aroma and flavour components of the primary wine sample and the sparkling wines sample taken during the main phase of the tank-fermenting process. This is essentially attributable to the fermenting activities of the yeasts. On the contrary, the aroma and flavour components of the primary wine sample agreed in quality with those of the sparkling wines sample taken at the end of tank-fermentation. It is concluded from these findings that greater amounts of new components do not form during the second fermentation. On the other hand, aroma and flavour components already present in the primary wine came to the fore by the quantitative increase of certain bouquet components. The comparison of the samples of bottle-fermented sparkling wines revealed, irrespective of slight changes, a clear-cut developmental trend. During the aging process, the contents of isopentanol and of a still unidentified component decreased, whereas those of isobutanol, isopropanol, heptanol and a still unidentified component increased markedly. It is stated that differences in the fermenting process manifest themselves mainly by the ratios of the components. The bouquet components were almost similar for both fermenting processes.