Final answer:
Jura Vin Jaune needs to mature for over 6 years in barrels before bottling. Wines claiming to be pre-1950 but showing cesium-137 are likely fake.
Step-by-step explanation:
You've asked about the aging process for Jura "Vin Jaune" wine. The Jura Vin Jaune must be matured for at least 6 years and 3 months in barrels before it can be bottled. This traditional aging process allows the wine to develop its unique flavor profile. Regarding the verification of old wines, it's important to note that before 1950, cesium-137 levels in the environment were negligible. If an old wine, claiming to be from before that year, shows measurable levels of cesium-137, it is likely a fake. Therefore, it's crucial to be cautious when considering the purchase of expensive vintage wines, as they may not be as old as claimed, regardless of the quality of the wine itself.