The domestic German wine market is so dominated by the cheap supermarkets that they cover a stable 48 percent of all wine sales, according to Ernst Büscher from the German Wine Institute (DWI).
Aldi is the biggest German wine seller, said Büscher, adding that the losers from this trend were specialist wine shops and those vintners who sold direct to consumers.
But quality - or at least price - was slowly rising, with the average price paid rising by 12 cents to €2.84 per litre, he said.
"We have been seeing that increasing numbers of retail shops seek to improve their image by stocking a good selection of wine," DWI manager Monika Reule said.
Overall domestic sales dipped a little last year, down by two percent to around 14.5 million hectolitres.
Exports of German wine rose by one percent in 2013 to 1.3 million hectolitre, with a quarter of this shipped to the United States.