The current invention provides an improved petroleum coking process wherein the risk of silicone poisoning of units downstream of the coke drums is eliminated. The method of the current invention controls the foam layer within the coke drum by injection of a non-silicone anti-foam agent, preferably a tire oil. In another embodiment, the current invention provides a controlled foaming method which increases the liquid production from the coke drum. In the controlled foaming method, an anti-foam agent is cyclically injected into the drum early in the coke drum fill cycle. The cyclic injections manage the foam layer without inducing the induction phase in the coke feedstock, thereby increasing the total volume of feedstock received by the coke drum.