But that quote also specifies that a loaf of bread was used, so why is that not standard instead of wafers, which while a form of bread are surely not the type of bread originally used?
It seems obvious to me that since the bread and wine are symbolic of Jesus's flesh and blood, and have already been altered to wafers and wine (or grape juice or water or black tea), that it can be altered to wafers and beer as well.
Analogy of wafer for bread can only extend as far as grape juice for wine (same base material processed differently), not using something different altogether.