Term for the "atypical ageing tone" or "atypical ageing note" in wine, emphasising the distinction from the "true ageing tone". There are many synonyms such as acacia, floor wax tone, hybrid tone, candle wax, Mediterranean note, furniture polish, naphtalone, wet cardboard, wet cloths, dirty cloths, mothball tone, moth powder tone, soap tone (soapy), nitrogenous, dull, detergent tone and washing powder tone. Aminoacetophenone (AAP) was identified as the responsible flavour component in 1993. The plant hormone indoleacetic acid is likely to have a high proportion as the starting substance.
Sensory change
It is a natural wine substance that only causes negative sensory changes at higher concentrations. The perception threshold is 0.5 µg/l (microgram = millionth of a gram), values between 0.5 and 1.5 µg/l are considered mild UTA. In aqueous solution, the substance causes a floral aroma of acacia and oranges; the typical UTA note is only produced when it interacts with other aromatic substances. Together with other substances, AAP is the cause of the foxy flavour of certain American vines, especially the Vitis labrusca species. This is why UTA wines often have this typical "fox flavour".
