Hi, Baker~
The research that you seek is easily found..
First, some basics on viniculture: Yes, wine is 'mostly' water, but the source of this water comes from grapes - it is drawn up thru the plant and is free of contaminants and bacteria - a 'pure' source, if you will, which wasn't a common occurrence in ancient days.
Note that water is not
added to wine during the fermentation process. Your statement alludes to this, but it only shows a lack of understanding on how wine is produced.
As such, typically wine would be safer to drink than water from many 'municipal' water souces, as the water did not come from a spring, river, etc., where it could have become contaminated. It was generated from the crushed fruit and further kept purer than typical groundwater sources by its alcohol content.
I submit the following..
Recent medical studies pointing toward the potential health benefits of moderate wine-consumption would not have surprised early wine-drinkers. In ancient Egypt, wine was believed to be a treatment for asthma and other afflictions. Soldiers routinely carried flasks of wine to mix with drinking water because the wine's alcohol killed some harmful contaminants.
December 15th, 2000
Wine in the Ancient World
By Jacob Gaffney - Wine Spectator Magazine
Although wine was typically employed during ceremonial occasions, there is no indication that Jesus insisted wine be drunk in his honor. The accusation, then, that employing water in the LDS sacrament somehow nullifies the event is rather silly.
Grace, see the above, and seek thee wisdom.
Have a great day!
-spike-