Sotolon (also known as sotolone) is a butenolide lactone and an extremely potent aroma compound, with the typical smell of fenugreek or curry at high concentrations and maple syrup, caramel, or burnt sugar at lower concentrations.

[5] This molecule is thought to be responsible for the mysterious maple syrup smell that has occasionally wafted over Manhattan since 2005,[6] with the source of the sotolon being a factory in New Jersey that processes the herb fenugreek.

[8] The compound was named in 1980 when it was found to be responsible for the flavor of raw cane sugar: soto (粗糖, sotō) means "raw sugar" in Japanese and the suffix -olon signifies that the molecule is an enol lactone.

[9] Several aging-derived compounds have been pointed out as playing an important role on the aroma of fortified wines; however, sotolon (3-hydroxy-4,5-dimethyl-2(5H)-furanone) is recognized as being the key odorant and has also been classified as a potential aging marker of these type of wines.

Despite being pointed out as a key odorant of other fortified wines, the researchers’ attention has also been directed to its off-flavor character, associated to the premature oxidative aging of young dry white wines, overlapping the expected fruity, flowery, and fresh character.