Question Two. Whether only Wine Pressed from the Grape is Fitting Matter for Conversion into the Blood

385. To the second question [n.361] I say that artificial wine, or any other wine that is not wine from the vine (as wine from apples or this sort of thing) is only wine in a certain respect and equivocally; hence nothing such is suitable for consecration into the blood.

386. The principal reason is that Christ instituted it thus.

The good fittingness is that the second principal part of nutriment, that is, drink, principally consists in wine, as in the principal drink. And on this there is Gratian Decretum p.3 d.2 ch.5.

387. The wine too should be pressed from the grape; for as long as the liquid is in the grape alone it has more the idea of the eatable than the drinkable. But this sacrament in the second part of itself essentially contains the blood, and something that is per se drink for the sign. And this too is in Gratian ibid. chs.6-7, “what is from pressed grape clusters, that is, the people communicate in grape grains, is very confused; but if necessary grape clusters may be pressed out into the chalice.”

388. The adding of water to this wine is not simply necessary, by necessity of the sacrament, because even when it is added it is not converted into the blood unless it is first converted into wine; and therefore a small amount is to be added, and so early that it can be converted into wine before the consecration (for the Greeks do not add water, as Innocent III says On the Sacred Mystery of the Altar IV ch.32, but this is necessary on the part of the minister because of the precept of the Roman Church). And Christ too consecrated wine in which water was first mixed, according to Damascene Orthodox Faith ch.80, “Christ handed the chalice of wine and water to his disciples, saying, ‘Drink you all of this; this is my blood etc.’.”

389. The fittingness of adding water to the wine is because of the mystery, to signify that the people are united to Christ the Lord, according to Gratian ibid. p.3 d.2 ch.7, “Since water is mixed with wine in the chalice, the people are united to Christ,” that is, it is signified that the people are to be joined to him through faith and worthy reception of the sacrament.