surviving "Isotonic" roman drinks recipes

[Gaius Julius Caesar]

I can share Fortunatus' more specific experiments with posca:

"Initially I used lots of red-wine vinegar mixed with red
wine to create this (supposedly) refreshing and ubiquitous legionary drink. But the end result was oily, burning, cloying and nauseating. Several attempts later I settled on a drink of water, with a dash of red wine vinegar, and a dash of red wine (vinum) added. On a two day march along Hadrian's Wall, over-heating, desperate for refreshment, this mix was refreshing. I drank the lot."

from: [url:3vrbhh7l]http://www.comitatus.net/rations.pdf[/url]

I have had refreshing results with simply diluting red wine :-) ) but I don't know what sort of ratio would actually result in an isotonic or near isotonic solution.

perhaps you should have added the honey? It was quite often used for energy in olden times....