I have heard it said that if the consecrated host decays and loses its appearance of bread it is no longer the body of our Lord, and that when cleaning the chalice they rinse it with water first to dilute any residue of the blood so that in losing its appearance of wine it is no longer Jesus’ blood. At what point of decay or dilution does the Eucharist cease to be? If wine is still present materially in the water but does not appear to be wine then it seems to me that it is still the precious blood. I asked my priest who tried to explain it to me but I don’t think we were understanding each other. Please tell me what I am missing, it seems that it should be simple but I can not grasp it.
The presence of the Lord is conditional on the appearances of bread and wine remaining such through and through. As soon as chemical change occurs, be it rotting, molding, souring, then the Lord is no longer present. Dilution alone would not seem to have the same effect.
The chalice is cleaned with water, the residue drunk by the priest. Then the chalice is wiped clean. There is no precious blood left in the chalice.
I think the idea is that once the species loses its accidents (outward characteristics) of either bread or wine, then it ceases to be in substance the body and blood. So, I suppose that once wine becomes so diluted that it loses the outward characteristics of wine–perhaps when it is so dilute that all color disappears and it tastes like water–it would cease to be the blood of Christ.