News/ Quality aspects of corks used in wine making. Influence on its characteristics
Study done by the Agricultural Engineer Carlos Daniel Vlah / Montevideo June 18, 2003. Technological Confirmation of Sintecor Expandable Synthetic Corks. Introduction Almost thirty years have passed since the first studies on Expandable Synthetic Stoppers appeared in the market. At present is it is impossible to leave them to one side if we wish to avoid old and current problems with our wines that are the consequences of the use of traditional corks. Nobody can deny that cork stoppers are potential carriers of aromas and flavors that are not those of our products, and so may cause undesirable changes in them. Equally well known are the risks of macrobiotic contamination and their derivations that originated a generic terminology - as J.J. de Castro Martín says; a not very happy one - under the catch-all phrase ?tastes of cork?. Efforts have been made the whole time to protect the cork industry by creating ever more sophisticated methods and work norms, to reduce the risks inherent in the handling of raw material that is originally natural and so is controlled by natural laws that man cannot completely dominate. These add to the costs of production and result in an industry overwhelmed by increased demand, not only in quantity, but also in quality. This is why the large companies ? worldwide ? have opted for new and innovative alternatives by using Expandable Synthetic Stoppers. In our specific case we made the following study which underlines the advantages of a stopper free from organoleptic carriers that complies with its basic premise: to keep intact the characteristics of our product. MATERIAL For the experiment 12 bottles were sealed with their corresponding repetitions. They were opened for the first time at 2 1/2 months for an espectrophotometric reading and tasting. It was our intention, in the first stage, to evaluate any difference between treatments. To do this we formed a panel for blind testing, using our numbered samples. At the same time the statistical results were obtained through the espectrophotometric analysis of each bottle. It is worth mentioning that from the results obtained it is possible to calculate indirectly the quantity of tannins passed to the wine from the corks in the cases where it was appreciable. Six months later the same tests were repeated. RESULTS: In the first evaluation there were no different parameters to mention in and amongst the samples, taking the totality of the bottles analyzed. In each tasting, emphasis was placed on the persistence of the bubbles, effervescence and possible aromas that could indicate the type of stopper used. We can objectively assure a full agreement. This shows clearly and definitely the results, with a valuation factor that is more than significant. In the same way, in all the samples the controlled pressures surpassed 5 bars, confirming the perfect hermetical qualities of these Stoppers. And in the last stage the above values and concepts are repeated. DEVELOPEMENT. In this case we were looking into certain aspects which are not related to the physical behavior of the Expandable Synthetic Stoppers, which have been well proven, but aspects related to the evolution of our product itself (naturally effervescent) in handling and storing situations identical to those employed, using the Champenoise method. We chose as a reference, or control, a brand of agglomerated cork Stoppers with a natural double disk that are used by several wineries in the area, and compared them to the Expandable Synthetic Stoppers. We started our study with the decollation of a batch of naturally effervescent. That batch was in a horizontal position, then placed on racks for 120 days to finish upright and the stoppers used for our test were introduced. INFORMATION RELATED TO THE WINE: Our wine base was a cut of two varieties, Chardonnay and Pinot which resulted in a pale yellow wine with a fruity aroma and marked acidity without being aggressive. Its taste is agreeable, having a young development that causes the citric aromas ? contributing to the sensation of freshness ? to be noticed on the retro-nasal area. CHEMICAL ANALISIS: 12° G.L. Alcohol; Total Acidity 4.0 gr./ I. Expressed in H2S04 Volatile Acidity 0.2 S02 Total 64.0 mgr./ I Reduced Acidity 12.0 gr. / I. PH 3.0. CONCLUSION: We state our absolute approval of the Sintecor Expandable Synthetic Stoppers, and, obviously, we never found a bottle with the famous ?taste of cork?. So now there is no possibility of the appearance of flavors from the formation of compounds such as 2,4,6 ? tricloroanisol (TCA) - which in concentrations of few ppt. change, negatively, the organoleptic characteristics of a wine. (Extract from a published work done by J.J. de Castro Martín titled ?Contribution to the study of grapes and delivery stoppers as quality factors of the wine cellars, April, 1989). As he expressed it so well in that publication, we can also avoid the problems of the fungicidal flora on the delivery cork stoppers if we chose the Sintecor Expandable Synthetic Stoppers. In cork stoppers its microflora is usually found in the lenticular canals of the cellular structure of the cork, and on the surface formed by handling. Studies done on microbiological contamination during the different stages of the cork stoppers show an appreciable number of colonies and, added to that, there are several possible sources of appearance of TCA. It is possible to recognize aromas that go from the typical chlorine to fungus. So, confronted with these problems, it is advisable to select Expandable Stoppers which have been more than tested and, for all these years, have been improved to reach the most demanding international norms in the wine for export. Confirmation of this appears daily in publications such as The Drinks Business, N° 3 of September 2002 and in N° 7 of February 2003