But Sebastião de Melo's greatest reforms were economic and financial, with the creation of several companies and guilds to regulate every commercial activity. He demarcated the region for production of Port to ensure the wine's quality, and this was the first attempt to control wine quality and production in Europe. He ruled with a strong hand by imposing strict law upon all classes of Portuguese society from the high nobility to the poorest working class, along with a widespread review of the country's tax system. These reforms gained him enemies in the upper classes, especially among the high nobility, who despised him as a social upstart.

Answer this question, if possible (if impossible, reply "unanswerable"): Why did e Melo demarcate the region for production of Port?
to ensure the wine's quality