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Verheerend wirken sich dagegen starke Tempera- turschwankungen aus. Die Geisenheimer Forscher bestückten Weinkisten mit Sensoren und verschiff- ten sie von Bingen nach Japan. Sodann stellten sie die Reise in ihrer Klimakammer nach. „Wenn sich die Containerfracht in der Sonne auf 50Grad aufheizt und nachts wieder abkühlt, entsteht eine Art Pumpwirkung“, so Jung. „Durch den Korken wird zu viel Sauerstoff angesaugt, und die Oxida- tion beginnt ihr schleichendes Vernichtungswerk.“
Die rund 20 deutschen Onlineshops und Auk- tionshäuser, die mit alten Jahrgängen handeln, achten denn auch streng auf die Vorgeschichte der Flaschen: Ware vom Dachboden wird nicht ge- kauft. Punktabzug bringen verschimmelte Etiket-
The drink of Dionysus, however, only slowly reveals its secrets. Example: The new decoding star of the guild, Axel Marschall, is pursuing the question at the wine research institute ISVV in the South of Fran- ce of why certain Bordeaux wines develop a swee- tish note even though they contain no sugar at all. His guess is that there must be „undiscovered mo- lecules that produce this taste“. But which ones?
6400 material compounds were discover- ed during the analysis of a merlot - half of which were unknown to the biochemists until then.
The fashionable word „minerality“ also cre- ates headaches. Sommeliers sometimes think of slate, re stone, or „wet rocks“ when tas- ting ne wines. A laboratory in Rioja recent- ly discovered that such „earthy“ fermenting pro- ducts contain succinic acid which tastes salty.
But in the earthy wines there is mainly a lot of phenylethyl alcohol and γ-decalactone. These substances smell of roses or peach. To date no one knows why they trigger the sensation of minerality.
But there are now solid results on the subject of storage. It‘s a myth that the bottles should lie on the shelf in wet cellars. The University of Geisen- heim has carried out a long-term experiment with upright bottles. „The cork also remains elastic when it is not washed,“ explains the oenologist Rainer Jung: „the air in the bottle neck is enough.“
On the other hand, strong temperature uctua- tions have a severe effect. The Geisenheimer rese- archers put sensors on cases of wine and sent them from Bingen to Japan. They then followed the journey in their climate chamber. „When the container freight is heated up to 50 degrees in the sun and cools down at night, a kind of pumping effect is created,“ says Jung. „Too much oxygen is sucked through the cork, and the oxidation begins its creeping destruction.“
The approximately 20 German online shops and auction houses, which deal with old vin- tages, also pay close attention to the prehis- tory of the bottles: they don’t buy goods from the garage. Points are deducted if the label is mouldy and the bottleneck has a low ll level
„Sometimes cork moths nest in the closu- res,“ says Jens Krau, 67, who heads the Bre- men wine auction house Koppe and Partner. In his storage the spoils of the past days are pi- ling up: „Pichler emerald“ boxes are next to 17-year-old magnum bottles of Dom Pérignon.
Krau rummages through the old wine cellar almost every day. Many customers also send him their pre- cious bottles by mail. Recently, the hunter of the fer- mented drops was in the castle vault of a nobleman.
© Deutsches Weininstitut (DWI)
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