The characteristic feature of the Tokaj-Hegyalja Wine Region is botrytisation, which occurs from year to year thanks to the combined properties of the cropland, the particular microclimate, the neighbouring rivers (Bodrog, Tisza) and appropriate grape varieties (Furmint, Hárslevelű, Muscat, Zéta, Kövérszőlő, Kabar). The mould that gives rise to the process of botrytisation (Botrytis cinerea) cannot itself be regarded as something unique to the wine region as it is also to be found elsewhere – unlike the cellar mould (Cladosporium cellare) covering the walls of the cellars hollowed out from rhyolitic tuff, which provides optimal conditions (temperature and moisture content) for wines during their maturation in wooden barrels.
During botrytisation, thanks to early autumn rains and dawn mists, the grapes swell and burst, triggering the noble rot process of botrytis. As a consequence of the special microclimate, the rainy season is followed by a lengthy warm and sunny period, promoting the botrytisation of the berries and concentration of flavour, succulence and sugar content.
The making of Tokaji Aszú is a tradition dating back centuries in the wine region. The first stage of the process is to pick the grapes from each cluster individually at harvest time and place them in vats, where they are stored until processing. During this time, the nectar that will be bottled as Eszencia trickles from the perforated vats under the Aszú berries’ own weight.
In the autumn of 2013, with a view to standardising the quality of Tokaj wines, new winemaking regulations were created in the wine region. For Aszú, the minimum sugar content was set at 120 g per litre. In addition, it was specified that wines produced here may be matured and bottled only at the place of cultivation, i.e. in a given settlement belonging to the wine region.