Bastardo is just one of the many allowable varieties for the production of Port - Portugal's famed fortified wine from grapes sourced from the steep terraced vineyards of the Duoro Valley. The Bastardo grape is generally not as highly regarded as other Port varieties, such as Touriga Nacional and Touriga Francesa. Bastardo's greatest virtue is the high natural sugar content of its grapes - a desirable characteristic for fortified wine production.