when does the bread and wine become the body and blood
Transubstantiation Transubstantiation (in Latin, transsubstantiatio, in Greek μετουσίωσις metousiosis) is, according to the teachings of the Catholic Church, the change of substance by which the bread and wine offered in the sacrifice of the sacrament of the Eucharist during the Mass, become, in reality, the body and blood of Jesus.
Baker's yeast It is not known when yeast was first used to bake bread; the earliest definite records come from Ancient Egypt.[9] Researchers speculate that a mixture of flour meal and water was left longer than usual on a warm day and the yeasts that occur in natural contaminants of the flour caused it to ferment before baking. The resulting bread would have been lighter and tastier than the previous hard flatbreads. It is generally assumed that the earliest forms of leavening were likely very similar to modern sourdough; the leavening action of yeast would have been discovered from its action on flatbread doughs, and would have been either cultivated separately or transferred from batch to batch by means of previously mixed ("old") dough. Also, the development of leavened bread seems to have developed in close proximity to the development of beer brewing, and barm from the beer fermentation process can also be used in bread making.