As the Bauern- und Winzerverbandes Rheinland-Pfalz Süd e. V. (BWV - farmer and vintager's union of Rhineland Palatinate South) stated in an interview, the unions president, Norbert Schindler, Member of the Bundestag, wrote a personal letter to the minister for viniculture Hendrik Hering and spoke against the approval of a general sweetening method of wines with RTK.
Schindler wrote in his letter that there is no way that this would be allowed of up to 4% alcohol. In the case of such a doubtful regulation, the BWV fears severe consequences for the domestic viniculture. Such a "supplementing" of domestic wines with RTK -which is imported most of the time- was an obstacle to the principle of clear origins of the wines and that this would lead to consumers being confused.
He wrote that the current regulation, according to which a small amount of sweetener of the same quality and origin is added to the wines to harmonically round them off, was entirely sufficient. With the new regulation, it would be possible to add RTK twice to the wines, the first time when adding to the juice before fermentation and then as a sweetener to the wine after fermentation. The BWV-president wrote in his letter to minister Hering that this could certainly not be a desired goal.
Schindler pointed out that, furthermore, the possibility of supplementing the wines with RTK could lead to severe economic consequences. Such an upgrading method of simple wines could also lead to the quality wine segment, which is so important for wineries, to be circumvented.
INFO: More about the process and results of adding RTK (PDF file) by oenologist Jürgen Köhler (German article) Bayerische Landesanstalt für Wein und Gartenbau LWG, Veitshöchheim.
*RTK (Rektifiziertes Traubenmostkonzentrat) is defined a liquid, non-caramelized product made of grape juice which is produced , in part by distillation, and also by many other methods. Basically it is a highly concentrated sugar syrup made of grape juice. (aw.yoopress)