Zacharonero, was a refreshment popular in Northern Greece, made by mixing 2 tbs sugar (zachari), 1 glass of water (nero) and 1 tbs vinegar. Adding more vinegar (about 3tbs) zacharonero becomes xidonero (xidi = vinegar + nero= water)
Vinegar in drinking water is effective in killing harmful bacteria and in eliminating the fever, thus xidonero had been heavily used as a way to purify the water and as a remedy for dysentery, malaria and typhoid fever.
It was also consumed as a cool, not very refined but very refreshing beverage.
Xidonero was actually close to posca, a drink of vinegar or acidified wine and water that was used by the Roman and Byzantine military troops and lower classes. It might be infused by herbs and sweetened by honey.
The evolution of the beverage industry affected many homemade refreshments. After 1960, zacharonero and xidonero unavoidably lost their way in terms of popularity.
History of Greek Food 