Excessive viscosity of the slip: causes & remedies

Viscosity (or viscous friction coefficient) measures a substance attitude on generating friction between its layers. In other words, it defines the resistance of the fluid to its proper flow.
The barbottina's viscosity values - that is the suspension of inorganic raw materials, water and dispersants that after the atomization process will form under the weight of the presses the raw ceramic body - can sometimes rapidly and suddenly change, and grow.
In the event of an excessive or out of standard increase, many critical issues may occur, compromising the use of the watery system or even forcing producers to repeatedly stop the production line.
What are the main causes that can significantly affect the viscosity values of the slip and what do we need to know the proptly act, avoiding the worst-case scenarios?