What do you do if you have too much consecrated bread and wine?
Some, confusedly, think that the piscina (sacrarium) is the solution. It is not.
There is the tradition, in church architecture, of having a piscina (sacrarium) near the altar, or in the vestry/sacristy. A piscina is a bowl with a drain that goes directly to the earth. [Technically, it is the drain that is called the sacrarium; some extend this term to the basin.]
The purpose of the piscina is to dispose of water from, for example, liturgical ablutions. In my experience the more normal practice is drinking the ablutions directly after communion, but a further wash of chalice and paten in the sacristy/vestry could have the water from that poured down a piscina there. A font preferably drains directly into earth – if not, the blessed water might be poured down the piscina. [Bad practice: directly after baptising someone at the west end of the church building, just as everyone was returning to the front, the priest reached down deeply into the font pulling the plug!] Holy oils, and remaining ash from Ash Wednesday can also be disposed of down the piscina.
Misunderstanding the role of the piscina, I have seen notices (all the way to cathedrals) directing the disposal of the consecrated Eucharistic elements down the piscina. I have seen this being instructed (all the way to bishops). [I have even heard of a priest “deconsecrating” the bread and wine! The mind boggles: was the Eucharistic Prayer said backwards?!]
The Roman Catholic Church could not be clearer:
Can. 1367 A person who throws away the consecrated species or takes or retains them for a sacrilegious purpose incurs a latae sententiae excommunication reserved to the Apostolic See; moreover, a cleric can be punished with another penalty, not excluding dismissal from the clerical state.
Using a piscina/sacrarium for this is specifically mentioned as forbidden at 107 here.
Anglican teaching and precepts on this are no different. For example, it is agreed in the formularies of the Anglican Church in Aotearoa, New Zealand and Polynesia that
Any remaining consecrated bread and wine, unless required for the communion of persons not present, is consumed at the end of the distribution, or immediately after The Dismissal of the Community. (A New Zealand Prayer Book – He Karakia Mihinare o Aotearoa, page 516).
Anglicans, like Roman Catholics, are only given two options: consume or reserve the Blessed Sacrament.
The Anglican approach is that people can mentally hold different models about what “actually” happens in the Eucharist, but in order that those holding this variety of acceptable models can worship together (in “Common Prayer”) we have an agreed practice.
Not even bishops can overrule our agreed practice. They, like anyone else, can seek to alter our agreements by the normal processes.
Historically some confusion may have developed, of course, when people have seen unconsecrated, left-over wine being poured down a piscina – which, of course, is perfectly acceptable. The tragedy is in communities where they are so poorly formed, trained, and careless that they themselves cannot distinguish what is consecrated and what is not.