A taste characteristic of certain American vines and the wine made from them, which is mostly to be understood negatively according to European taste (surprisingly, this tone is perceived as pleasant in Japan). Other names for Foxton are fox taste, fox taste, cat oak, skunk tone and bug taste. The also very often used term hybrid tone is actually misleading, because by far not all hybrids have this tone. The name Foxton was chosen because of the similarity of the scent around a fox's burrow or the smell of fox urine (cat urine), wet fox fur and animal faeces. This is particularly pronounced for the species Vitis labrusca (also fox vine or strawberry vine) and somewhat less so for the species Vitis rotundifolia or its descendants and cross-breeding products.
There are, however, other American vine species that exhibit the aroma, albeit to a lesser extent. The substance 2-methylantrantranilic acid (anthranilic acid methyl ester) was identified as the main cause of the Foxton as early as 1921. However, it is not the only one responsible for this, because in 1993 2-aminoacetophenone was identified as a further cause. The latter is also the cause of the wine defect UTA (atypical ageing tone). The content of these compounds increases continuously in the berries with grape ripeness.
Always associated with this penetrating wine defect is the strawberry aroma/tone, which is much more pleasant from a sensory point of view, but is also foreign to wine. The wine has a typical taste of strawberries (raspberries, hawthorn). 2,5-dimethyl-4-hydroxy-2,3-dihydrofuran-3-one (furaneol) was identified as the causative substance. While in the American vines and their direct descendants 2-methylantrantranilic acid, i.e. the foxtone, is by far predominant, in further back-crossings with European vines this lacking tone is more and more receding into the background and the strawberry aroma becomes more noticeable. An example of this interplay are the Castor and Pollux varieties, which have a distinct strawberry note but only a weak Foxton.
With more precise analytical methods, all three substances mentioned above could be detected in traces next to each other even in pure European varieties, but without sensory influence due to the low concentration. Although, according to current knowledge, fox clay and strawberry aroma always occur together in grapes in different intensities, they are regarded as two separate wine faults. They should therefore not be subsumed under Foxton, which is the case in most publications. Wines or wine-like beverages made from Labrusca varieties are Americano (Switzerland), Fragolino (Italy) and Uhudler (Austria).
Source: Detecting wine faults / Edmund Lemperle (Ulmer-Verlag)