It does, but in order to dodge the "but it look like a biscuit, checkmate papists!" Argument there was some clarification on how that happens exactly.

Or to use the catechism

What is the meaning of transubstantiation? Transubstantiation means the change of the whole substance of bread into the substance of the Body of Christ and of the whole substance of wine into the substance of his Blood. This change is brought about in the eucharistic prayer through the efficacy of the word of Christ and by the action of the Holy Spirit. However, the outward characteristics of bread and wine, that is the “eucharistic species”, remain unaltered.

Is this copium? A bit, but there's also a few different schools of thought on this even within doctrine so they keep the mechanism a bit vague.