Petroleum cokes derived from extra-heavy crude sources can be made more amenable to quenching by adding water or a water/light oil mixture to the coker feed downstream of the furnace. The coke product resulting from this addition of normally volatile liquids to the hot coker feed is still relatively dense but is more friable and usually is in a compact, relatively free-flowing, granular form. The coke is more amenable to uniform quenching in the drum and so can be cut and discharged with a reduced risk of eruptions and a reduced risk of fires in the coke pit or when the coke is subsequently handled and transported.