We do not know if the distillation was not known. We just do not have evidence that it existed. Technology necessary to produce distilling equipment was available.
It is extremely unlikely that distillation of alcoholic beverages was known to the Ancient Greeks. Once distillation took off at the point when it is documented in the early first millennium, it swiftly spread through Eurasia. It beggars belief to think that the Homeric-era Greeks had these beverages and kept them to themselves.
