‘Second, the association of the Lord’s Supper with a meal is strongly evidenced┬áby the food and drink distributed and enjoyed in it. The signs of bread and wine in the Lord’s Supper have no more been arbitrary or accidentally chosen than the water in Baptism. In the sacrifices of the Old Testament, flesh and blood were of primary importance, since they typologically pointed to the sacrifice of Christ on the cross. Yet the Lord’s Supper itself is not a sacrifice, but a memorial of the sacrifice made on the cross, and expresses the communion of believers with that sacrifice. For that reason, Christ did not choose flesh and blood but bread and wine as food and drink in the Lord’s Supper, to indicate thereby that it is not a sacrifice but a meal-a meal on the basis of , in memory of, and as an exercise of communion with, the crucified Christ. To that end, the signs of bread and wine are eminently suited. In the east, they were regular constituents of a meal. Everywhere and at all times even now they are easy to obtain. They are the chief means for strengthening and rejoicing the human heart (Psalm 104:15) and a graphic symbol of the communion of believers with Christ and one another. In this connection, it is immaterial whether the bread is made of wheat, rye or barley and whether the wine is red or white; Whether the bread is leavened or unleavened; and whether the wine is unmixed, or mixed with water. In none of these points has Christ specifically laid down or prescribed anything. The Reformed did not even hesitate to say that in the event bread or wine were definitely lacking, another food and drink, say rice or nutritious food, could be used as sign in the Lord’s Supper. This is not to say, however, that any arbitrary departure from the institution of Christ is permissible. Just as in or time, so in the early centuries there were some Christians (Tatians, Severians, Gnostics, Manichees, Aquarii) who prompted by an ascetic principle, substituted water for wine at the Lord’s Supper. But we must not be wiser than Christ, who expressly designated wine as the sign of His blood and whose command in this matter has at all times been followed by the Christian church.”

Bavinck’s Dogmatics
Vol 4; page 563-564