Q. 1. I heard that if the Consecration during the Holy Mass is not properly performed, there is no Consecration, nor a valid Mass. What determines the validity of the Consecration?
A. 1. During the Holy Mass, the Consecration is only valid when the priest has said the exact words prescribed by the liturgy of the Catholic Church during both, the elevation of the Bread that turns to the Body of Christ, and the elevation of the Wine that turns into the Blood of Christ.
These words are universal, meaning they are identical throughout the world, and they cannot be changed by the priest for whatever reason.
If the priest consecrates the Host into the Body of Christ and forgets to consecrate the Wine into the Blood of Christ, while it is suspected that the Host has turned into the Body of Christ, at the same time, it is not a valid Mass. For the Holy Mass to be valid, both species must be consecrated.
Suppose an older or sick priest consecrates the Host, but he uses the words for consecrating the Wine, or vice-versa, the Mass is not valid. Again, I repeat, both species must be consecrated with their appropriate words for a Holy Mass to be valid.