This invention is a new and distinct grapevine variety denominated ‘IFG Twenty’. The new grapevine is characterized by producing naturally large seedless blue-black berries having a narrow ellipsoidal to cylindrical shape with a strong fruity labrusca flavor. Fruits normally ripen mid to late season about early to mid-September near Delano Calif. Fruits are fairly low in acidity, with medium dense firm texture, occasionally noticeable seed trace. Vines are productive and can be spur pruned.
