Ruen is an almost extinct cross between Melnik (Broad Leaved Melnik Vine) en Cabernet Sauvignon created in Pleven, Bulgaria in 1951 and officially released in 1964. Just like the Rubin grape variety, Ruen is only cultivated in the Struma River Valley in South-western Bulgaria. The grapes ripen late September. Berries are dense, dark blue 
in colour, the skin is rich in colouring matter, and the juice is colourless.

The wines from Ruen are dark-red and fresh. They mature and develop very well in oak barrels.