sotolon, compound (3-hydroxy-4,5-dimethyl-2(5H)-furanone) formed from acetaldehyde that is an important component of the spice fenugreek and is found in a wide range of products from botrytized wines to roasted tobacco. It is responsible for the hazelnut and particularly spicy ‘curry’ aromas found notably in vin jaune from the Jura but also in tokaji and some fortified wines including vin doux naturel and port, especially those that are rancio. It forms partially during the ageing process, particularly if this is oxidative, but in vins jaunes it is known to increase after bottling. It is also commonly identified by a honey or beeswax aroma in wines suffering from premature oxidation. Discovered by Japanese scientists in the late 1970s as a flavour compound in raw cane sugar, sotolon has a very low flavour threshold (7 μg/l) and is formed in carbohydrate-rich media.