There are still certain questions regarding mycelium growth during blow down. Sometimes mycelium grows more than at other times. In other words, vegetative growth doesn't always proceed to generative growth at the same pace. One of the most important aspects of the incubation period is the time of blow down but the evenness of colonization also plays a major role.
Ensure at all times that filling then casing or filling and casing simultaneously is done as evenly as possible. This encourages mycelium to grow uniformly towards the surface so it is easier to determine the right moment for blow down. If growers want to blow down gradually to steer the spread of pinheading, the mycelium must be given an extra chance to continue growing. Don't start too late; otherwise the surface will become too white with the risk of fruits drying out.
Many growers spray to check the mycelium if it threatens to overdevelop. However, remember that the cold water temperature will cause earlier pinning and the formation of clusters of pinheads.
Jos Buth, C point