The reason that the Coptic Church mixes the wine with water, and uses leavened bread, is based on the belief that Christ did these things Himself.
According to the Liturgical Tradition of the Coptic Church
, the priest chants at the Consecration
: “Likewise after supper He took the Chalice, and mixed it of wine and water.”
Regarding the use of leavened bread, H.G. Bishop Angelos states in his article on the Coptic Faith
: “The Coptic Church also uses ordinary (that is, leavened) bread, for the offering. The Coptic Church has always taught, what most scholars now acknowledge, that the Last Supper took place one day before the Passover, and thus Christ used leavened bread.”
With respect to the symbolic significance of this, Fr Tadros Malaty comments in his book Christ in the Eucharist
, page 103: “The holy bread is leavenedÃƒÆ’Ã‚Â¢ÃƒÂ¢Ã¢â‚¬Å¡Ã‚Â¬Ãƒâ€šÃ‚Â¦for the yeast refers to our wickedness, which Jesus carried in His Holy Body and entered into the fire of the Cross.”