It is through this expression of the early Church that we arrive at the understanding that transubstantiation was not some scholastic novelty of Trent. So rather than use the word "metaphorically" the word miraculous should be used. For that was the Patristic understanding."
I can list a number of top flight patristic writers who explicitly (and without controversy among their contemporaries) describe the elements of the Lord's Supper as metaphor. I'll hold off on that and give you a chance to list some, or any patristic writer who spoke in terms of the bread and wine losing their substance as bread and wine and becoming entirely the body and blood of Christ, but undetectably so in respect to how we perceive them physically. Remember, equivocal language will not do. If the saying *could* be a vivid metaphor, or *could* allow the bread and wine to remain as bread and wine (as in sacramental union or spiritual presence), then that is a failure to unequivocally support the specific teaching of Trent regarding transubstantiation. So ... what have you got?
Indirectly the Fathers express their belief in Transubstantiation whenever they deny, as they often do, that the bread and the wine continue to exist as independent substances after the consecration, or affirm that the terminus ad quem of the conversion that takes place in the Eucharist is the true Body and Blood of Christ. Thus St. Cyril of Jerusalem says: Μεταβάλλεται καὶ οὐκέτι ἄρτος. St Ambrose: “Species elementorum mutatur.” Cyril of Alexandria declares that the bread is changed into the true Body of Christ; Chrysostom, that it becomes His crucified Body; Ambrose, that it is converted into the Body born of the Virgin Mary.
The so-called Liturgy of St. Chrysostom contains this beautiful prayer: “Send down Thy Spirit upon us and these Thy gifts [i. e. the Eucharistic elements], make this bread into the precious Body of Thy Christ. (Deacon: Amen). But that which is in the Chalice make into the precious Blood of Thy Christ (Deacon: Amen), converting it (μεταβαλών) through Thy Holy Spirit (Deacon thrice: Amen).… The Lamb of God, the Son of the Father, is broken and divided—broken but not diminished, everlastingly eaten but not annihilated, sanctifying those who partake thereof.”
The following invocation is from the Liturgy of St. Basil: “Make this bread into the precious Body of our Lord and God and Redeemer Jesus Christ, and this chalice into the Blood of our Lord and God and Saviour Jesus Christ, which was shed for the life of the world.”
In the Armenian Liturgy we read: “Consecrate this bread and wine into the true Body and the true Blood of our Lord and Redeemer Jesus Christ, changing (permutans) it through Thy Holy Spirit.”
The Mass formularies of the Western Church are equally expressive. The ancient Gothic liturgy says: “This is the Lamb of God, which, being sacrificed, never dies, but, though slaughtered, lives everlastingly.… May the Paraclete descend, that we may partake of the sacrificial gift in heavenly conversion, and that, after the consecration of the fruit [bread] into the Body, and of the chalice into the Blood, it may conduce to our salvation.”
An ancient Gallican Missal contains the following prayer: “May the fulness of Thy Majesty, O Lord, … descend upon this bread and upon this chalice, and may [it] become unto us the legitimate Eucharist in the transformation of the Body and Blood of the Lord.”
So in the end it is lex orandi, lex credendi : how we pray is how we believe. Whether its unequivocal enough is for you to decide. That's a man-made imposition in any event. Do the ECF's repeat word for word the thomistic understanding of Transubstantiation? No. Is transubstantiation as defined at Trent new? No. It's always important to understand the ECF's in full context and in harmony with what they believed.
Pohle, J., & Preuss, A. (1917). The Sacraments: A Dogmatic Treatise (Vol. 2, p. 121). St. Louis, MO; London: B. Herder.