It is found that the minimum bubbling velocity of aerated fine powder can be defined by experimentally measuring incremental elastic deformation coefficient (Upsilon). The value of Upsilon starts changing at a certain degree of powder expansion. The sudden change of Upsilon indicates the initiation of the fractures in the homogeneously aerated expanded (HAE) emulsion phase. The intrinsic minimum gas velocity (U-mb*), which causes this fracture initiation, can be significantly smaller than the so-called minimum bubbling velocity (U-mb) defined by the classical concepts.