Quintal (English language) or Quintale (Italian) is a term of measurement for 100kg used to express the yield of eg. grapes. A yield of 80 quintali and a resa of 70 per cent would give 56 hl per hectare (David Gleave MW: 1989, p.12). To calculate the approximate hectolitres per hectare Nicolas Belfrage MW (2003, p.40) suggests multiplying the number of tonnes (1,000kg) by 7. Thus ten tonnes of fruit will yield approximately 70 hl of wine.
David Gleave MW, ‘The Wines of Italy‘ (Salamander Books, London, 1989).
Dr Ian D’Agata, Native Wine Grapes of Italy (University of California Press, 2014), p.570.
Nicolas Belfrage MW, From Brunello to Zibibbo—The Wines of Tuscany, Central and Southern Italy (2nd edition, London, 2003.