The white wines of the island are composed primarily of Forastera (at least 65% according to DOC regulation) and Biancolella (up to 20%) with up to 15% of other local grape varieties such as Arilla and San Lunardo. Grapes are limited to a harvest yield of no more than 10 tonnes/ha with a finished minimum alcohol level of at least 11%. For wines labeled as "Bianco Superiore", the yield is further restricted to a maximum of 8 tonnes/ha with a minimum alcohol level of 12%. Only certain subareas of the Ischia DOC can produce "Bianco Superiore" with the blend needing to contain 50% Forastera, 40% Biancolella and 10% San Lunardo.