This paper reports on a study of several grape native phenolic compounds in five red minor grapevine varieties in danger of extinction in Castilla-La Mancha. The study was performed in different vinification stages not previously reported in conjunction in that kind of grape varieties: skins (before and after vinification), must, during alcoholic fermentation, and after alcoholic and malolactic fermentations. The skins of Rojal showed the highest amount of flavonols and (+)-catechin, being optimal to favor co-pigmentation processes by co-fermentations and/or to develop young rosé wines. Moravia Agria (skins and wines) could improve red wine color in co-winemaking due to its high quantity of anthocyanins. In addition, Bobal, Tortosí, and Moravia Dulce could produce wines with their own entity and be used as young monovarietal wines or even with a short aging. This study could help to diversify oenologic market by minor grape varieties not normally used in other viticultural regions.