Roncal D.O. is a traditional, unpasteurized, hard cheese made from sheep's milk. It has a hard, natural rind covered with a velvety-smooth layer of beige-gray mould.
Aging period lasts at least four months. The firm, elastic interior is slightly grainy, with small, irregular holes. The greenish moldy surface is occasionally covered in olive oil.
The flavor owes much to the richness to the milk. It has a sweet, herbaceous flavor, thanks to the natural pastures of wild grasses, herbs and flowers on which the sheep graze.
As Roncal ages it becomes increasingly tangy. It has a hard beige to gray rind with beige interior which turns to amber with age.
A similar cheese is the Spanish Manchego.
In order to comply with US FDA regulation for export to the USA the maturation of this cheese has been extended to over 60 days.