According to DOC requirements, Vernaccia di Oristano grapes are limited to a maximum harvest yield of 8 tonnes/hectare (≈ 0.53 tons/acres).
For unfortified styles, the finished wines must attain a minimum alcohol level of at least 15% to attain DOC designation while the fortified liquoroso styles (both dry and sweet) must contain at least 18% alcohol by volume [REF].