Proportion of Wine and Water

Date: September 23, 2023
Author: Fr. Edward McNamara, LC

Answered by Legionary of Christ Father Edward McNamara, professor of liturgy and sacramental theology and director of the Sacerdos Institute at the Pontifical Regina Apostolorum University.


Question: Due to celiac disease diagnosis and doctor’s orders not to consume any gluten whatsoever (i.e., low-gluten host), I have permission from my pastor to bring my own small (celiac) chalice to Mass to receive the Precious Blood from it. Before the first Mass I attended with the pastor, he asked if I would like him to pour a small amount of wine into the chalice. Since previous priests have poured a copious amount of wine into my little chalice, I responded “yes” to the pastor, who told me that he prefers only a tiny bit of wine. To my shock, when I received the Precious Blood, I discovered that the pastor had poured hardly any wine into my chalice. And the tiny bit that trickled down the chalice tasted like watered-down wine, leaving me seriously doubtful that what I had received was valid matter. I am concerned that if the pastor prepares his chalice as he did mine by placing only a tiny bit of wine and an equal or greater proportion of water in it, then the matter in his chalice is also invalid and that the Masses that he is celebrating are, consequently, invalid. I am not sure how to proceed. -- E.R., Orange County, California


Answer: The procedure of distributing only the Precious Blood to those with celiac disease is legitimate and, in many cases, the preferred option.


I think our reader should approach the pastor and request him to put a little more wine in the small chalice, perhaps with guidelines such as a third or half full. This would resolve any fear that the wine would be diluted with the added drop of water.


Usually, when a priest says he uses only a little wine, he often means in relationship with the chalice and how much it is full. Most chalice cups, especially older chalices before the advent of concelebrations, contain only a small amount of wine, even if almost filled. In most cases, the drop of water added is negligible and will not affect the validity of the matter.


Even though the priest has stated that he uses little wine, he is probably using a relatively larger chalice which will contain sufficient wine. In my experience, priests who say they use only a small amount of wine usually mean that they pour in only as much as is necessary to absorb the host's fragment placed in the chalice before communion. Since the amount of water added is usually only a symbolic drop, the little wine is still sufficient for validity.


Thus, unless it is obvious that the priest adds excessive water to his chalice, one can reasonably exclude any doubt regarding the validity of the matter consecrated by the priest in the case at hand.


In the case of our reader’s small chalice, it could happen that from the priest’s perspective, the chalice has sufficient wine even though it is very little. Therefore, there is a very slight chance that the water added could affect the validity, although a probably higher probability that it could simply affect the taste and make it seem more diluted. I think that requesting that the priest fill the chalice to a certain level, as mentioned above, will eliminate any danger or doubt.


In the abstract, the Mass would be invalid if all chalices contained invalid matter by being overly diluted so that there was more water than wine.


If at least one chalice contained valid matter, the Mass would be valid, but the diluted chalices would not be the authentic Blood of Christ. This would be gravely illicit as some faithful would be unknowingly induced into performing an act of material idolatry.


In the case that it was discovered that all chalices contained invalid matter before distributing communion, the priest the priest could proceed according to the General Instruction of the Roman Missal:


“324. If the priest notices after the consecration or as he receives Communion that not wine but only water was poured into the chalice, he pours the water into some container, then pours wine with water into the chalice and consecrates it. He says only the part of the institution narrative related to the consecration of the chalice, without being obliged to consecrate the bread again.”


But great care should be exercised into assuring that should incidents do not occur. As the 2004 instruction, Redemptionis Sacramentum clearly states:


“50. The wine that is used in the most sacred celebration of the Eucharistic Sacrifice must be natural, from the fruit of the grape, pure and incorrupt, not mixed with other substances. During the celebration itself, a small quantity of water is to be mixed with it. Great care should be taken so that the wine intended for the celebration of the Eucharist is well conserved and has not soured. It is altogether forbidden to use wine of doubtful authenticity or provenance, for the Church requires certainty regarding the conditions necessary for the validity of the sacraments. Nor are other drinks of any kind to be admitted for any reason, as they do not constitute valid matter.”


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Readers may send questions to Please put the word "Liturgy" in the subject field. The text should include your initials, city, state, province, or country. Father McNamara can only answer a small selection of the many questions that arrive.

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