Process for producing a synthesis gas product containing hydrogen and carbon oxides from an input gas containing hydrocarbons, preferably natural gas or naphtha, comprising the steps of: (a) providing the input gas containing hydrocarbons, preferably in desulfurized form, (b) introducing the input gas into an input gas superheater, wherein the input gas superheater is configured as a single-stage or multi-stage heat exchanger whose heat exchanger stages are all in an indirect heat exchange relationship with a steam reforming flue gas, heating the input gas in the input gas superheater to a steam reforming entry temperature, discharging the input gas heated to the steam reforming entry temperature from the input gas superheater, (c) directly introducing the input gas heated to the steam reforming entry temperature into a main reforming stage, converting the input gas in the main reforming stage under steam reforming conditions in a multiplicity of reformer tubes filled with a solid, particulate reforming catalyst to afford a raw synthesis gas containing hydrogen, carbon oxides and unconverted hydrocarbons, wherein the reformer tubes are arranged in a reformer furnace whose interior is heated using a multiplicity of burners to form the steam reforming flue gas and wherein the steam reforming conditions comprise addition of steam to the input gas containing hydrocarbons and adjustment of a steam/carbon ratio, (d) discharging the raw synthesis gas from the main reforming stage and supplying the raw synthesis gas to at least one further purifying, conditioning or processing step, wherein performance of the at least one further purifying, conditioning or processing step affords the synthesis gas product containing hydrogen and carbon oxides, characterized in that (e) an analytical method is used to determine the concentration of unsaturated C 2+ -hydrocarbons in the input gas heated to the steam reforming entry temperature directly after discharging thereof from the input gas superheater and directly before introduction thereof into the main reforming stage, (f) the determined concentration of unsaturated C 2+ -hydrocarbons is compared with a predefined maximum value, (g) water or steam having a temperature lower than the steam reforming entry temperature is added to the input gas upstream of the one heat exchanger stage or between two heat exchanger stages of a multi-stage heat exchanger of the input gas superheater in the case the determined concentration of unsaturated C 2+ -hydrocarbons is above the predefined maximum value. (a) providing the input gas containing hydrocarbons, preferably in desulfurized form, (b) introducing the input gas into an input gas superheater, wherein the input gas superheater is configured as a single-stage or multi-stage heat exchanger whose heat exchanger stages are all in an indirect heat exchange relationship with a steam reforming flue gas, heating the input gas in the input gas superheater to a steam reforming entry temperature, discharging the input gas heated to the steam reforming entry temperature from the input gas superheater, (c) directly introducing the input gas heated to the steam reforming entry temperature into a main reforming stage, converting the input gas in the main reforming stage under steam reforming conditions in a multiplicity of reformer tubes filled with a solid, particulate reforming catalyst to afford a raw synthesis gas containing hydrogen, carbon oxides and unconverted hydrocarbons, wherein the reformer tubes are arranged in a reformer furnace whose interior is heated using a multiplicity of burners to form the steam reforming flue gas and wherein the steam reforming conditions comprise addition of steam to the input gas containing hydrocarbons and adjustment of a steam/carbon ratio, (d) discharging the raw synthesis gas from the main reforming stage and supplying the raw synthesis gas to at least one further purifying, conditioning or processing step, wherein performance of the at least one further purifying, conditioning or processing step affords the synthesis gas product containing hydrogen and carbon oxides, (e) an analytical method is used to determine the concentration of unsaturated C 2+ -hydrocarbons in the input gas heated to the steam reforming entry temperature directly after discharging thereof from the input gas superheater and directly before introduction thereof into the main reforming stage, (f) the determined concentration of unsaturated C 2+ -hydrocarbons is compared with a predefined maximum value, (g) water or steam having a temperature lower than the steam reforming entry temperature is added to the input gas upstream of the one heat exchanger stage or between two heat exchanger stages of a multi-stage heat exchanger of the input gas superheater in the case the determined concentration of unsaturated C 2+ -hydrocarbons is above the predefined maximum value.