Grapefruit juice to extract herbs for tincture I tried searching my question on google and did not find anything. I am looking to extract herbs with pure 100% grape juice http://www.lakewoodjuices.com/product_detail/id-32/  ( it is pasteurized ) instead of using the old school method of extracting with a 50% alcohol solution. 

My theory as of now would be that it would be more beneficial and it would  ferment or extract the same plus the extra beneficial minerals of the juice. I am wonder what your opinion on this is. Do you think it would extract the same and be just as beneficial as a tincture? Would it be more beneficial? How long should I let it sit for? should I let it sit at room temp or in cooler temp say, $45 ^\circ \mathrm{F}$?
Use the old school method and extract with aqueous ethanol. It is more efficient and more healthy:


The solubility of most compounds to be extracted from herbs is likely to be much higher in ethanol than in water (or juice). You get more out of the plants. 
The juice was initially pasteurized, but once opened, it will not necessarily stay free from microbes and/or might get mouldy. The risk of infections is definitively lower when staying with aqueous ethanol for extraction.