 Good quality Prošek is usually much more expensive by volume than other wines due to an average of seven times more grapes being needed to make the same amount of wine.While it can vary in the maximum amount, the alcohol level needed to be certified as a true dessert wine must be at least 15%.The composition is typically of Bogdanuša, Maraština, and/or Vugava (all native Croatian white grapes) with higher-end versions being a blend of the base white grapes and Plavac Mali (a red Croatian grape).