White wine the death knell of northern viticulture. The vine disappeared from northern Germany and Baden, and the maximum altitude for viticulture descended to 220 metres. Hans-Jürgen Otto noted that: "all the vineyards suffered and decreased in area". In England the vine also disappeared. The less early vineyards preferred to select white varieties of grapes because, even if unripe, white grapes allowed wine that was a little sour to still be consumable, while red grapes do not give enough colour and green tannins make the wine bitter. The interruption of the fermentation by a cold winter led to the discovery of the
Seibel grapes only four parent grapes: two European (Vitis Vinifera) grapes: Aramon and Alicante Bouchet … one wild American grape: Jaeger 70 (V. Rupestris x V.Lincicumii)… and one rootstock, AxR1, which was created by crossing Aramon with a wild American Vitis Rupestris. Although Seibel bred tens of thousands of grapes, he did so almost entirely by continually crossing and re-crossing his original varieties, all of which were descended from the original four vines, so the basic gene pool of his collection remained largely unchanged. Almost all later grapevine hybridizers, such as Bertille Seyve and his father-in-law Victor Villard, would simply breed one