Even though this is a separate chapter from Chapter 4 which provided the instructions for the blessing of the bread, the blessing of the wine (and in modern practice, water) is a continuation of how to perform the sacrament ordinances. Therefore, it is assumed that the physical descriptions from Moroni 4:1–2 continue to apply. Those authorized to administer the sacrament will kneel to pray.
In the Old World, wine was used specifically as an apt symbol for the blood of Christ. The two elements were bread and wine, or body and blood. Symbolically (as suggested in the comments on Moroni 4:3), the bread represented the victory over physical death. The blood represented the victory over spiritual death, the facilitation of the ability to repent, and to, therefore, be forgiven.
Although water doesn’t hold the same color symbolism, it is yet essential for life, and fits into the context of Christ being the “water of life” (Revelation 21:6). We do not know what liquid the New World saints used. There is some indication that there were grapes, but as with our modern substitution of water for wine, the particular liquid is less important than its symbolic meaning.
As with the bread, the wine (or water) is not for nourishing the body, but rather the soul. It is also a call to the remembrance of covenants.
Both prayers end with the blessing that we “may always have his Spirit to be with [us].” These are not physical blessings, but spiritual ones; therefore, it is the Spirit that will be with us; not earthly elements, but a spiritual presence.