This entry (already in Hesychius zeta202) uses the later spelling of beer, zu/qos, which is found in most sources except early papyri, where zu/tos is used. Manuscripts often give an acute accent, but Photius (Lexicon zeta61) has circumflex, and the word appears in verse with a long vowel.
The word is used in reference both to Egyptian beer and to the beer of northern nations. See LSJ s.v. (web address 1 and web address 2) and OCD(4) s.v. 'food and drink'.
For the effects of beer-drinking, see epsilon 1870; for barley see generally kappa 2412, kappa 2418.