I add nothing to any of my juices. I try to juice in their own liquids, but this is impossible if there is not enough juice, then I add a minimum of water to facilitate.
Commercial juicers are deficient in that they remove all the fiber. I utilize all the plant except for the gross cellulose, which should never be ingested by humans.
The mechanical Champion juicer is a scraper. The best on the market. It extracts the mostest, but is not essential. It was given to me.
I call my process juice but it is really a drinkable slurry, I have pressure canned probably 4000 liter jars of produce and never had a jar go bad. And I enjoy them all I might add.
My motive was/is stimulated by the view that there is something drastically wrong with our commercial food supply evidenced by the 60% obesity statistics. This is my small effort to do something about it, such as it is. I grow most but live in an area where what I don't grow is readily available from local producers. I am always adding new food as they become available. I am retired and have the time to experiment.