Until the middle of the 19th century Chianti was based solely on Sangiovese grapes. During the second half of the 19th century Baron Bettino Ricasoli who was an important Chianti producer and, in the same time, minister in Tuscany and then Prime Minister in the Kingdom of Italy, imposed his ideas: from that moment on Chianti should have been produced with 70% Sangiovese, 15% Canaiolo and 15% Malvasia bianca (Malvasia bianca is an aromatic white grape with Greek origins). During the 1970s, producers started to reduce the quantity of white grapes in Chianti and eventually from 1995 it is legal to produce a Chianti with 100% sangiovese, or at least without the white grapes. It may have a picture of a black rooster (known in Italian as a gallo nero) on the neck of the bottle, which indicates that the producer of the wine is a member of the "Gallo Nero" Consortium; an association of producers of the Classico region sharing marketing costs. Aged Chianti (38 months instead of 4-7), may be labelled as Riserva. Chianti that meets more stringent requirements, (lower yield, higher alcohol content and dry extract) may be labelled as Chianti Superiore. Chianti from the "Classico" sub-area is not allowed in any case to be labelled as "Superiore".