Abstract: The invention concerns a system for roasting coffee beans comprising: —a roasting apparatus (1), said apparatus producing smoke, and—a smoke treating unit (2) configured to collect and treat smoke produced by the roasting apparatus, wherein: —the roasting apparatus comprises a smoke outlet (11), and—the smoke treating unit comprises: a smoke inlet (21) configured to cooperate with the smoke outlet of the roasting apparatus, a smoke filtering sub-unit (22) comprising at least an active carbon filter (221), a smoke driver (23) configured to circulate smoke through the smoke treating unit from the smoke collecting device to an outlet (25) of the smoke treating unit, wherein the smoke treating unit (2) comprises an air inlet (24) configured to mix the smoke produced by the roasting apparatus (1) with ambient air before the smoke is circulated through the smoke filtering sub-unit (22).