As of today, cupola-type units have rather wide range of use both for iron production or metal scrap remelting and for mineral melt production. The major fuel type for such units is solid fuel -cupola coke. Raw material market offers quite a wide range of such fuels to the factories. Their metallurgical properties based on certificate data may vary within a broad band. To determine the impact of coke grain size composition on its properties, 11 coke types from various manufacturers were selected. An actual property variation range of certain solid fuel types was identified to describe the nature of solid fuel impact on cupola shaft furnace performance. When studying the combustion properties of coal coke in conditions close to the cupola shaft furnace, operation data of total curve of differential scanning calorimetry (DSC) was used.Temperature ranges were specified for intensive heat evolution from the beginning of coke sample active oxidation to the completion of the burnup period, as well as apparent heat capacity and heat effect of coke combustion.