This study suggest that the best herbal menstuum to use in extracting isoflavanoids might be a combination of
ethanol (70%)/
DMSO (5%)/
water (25%).http://naldc.nal.usda.gov/download/9382/PDF Quote:
In the present study, optimum isoflavones recoveries from soybean samples were obtained with dimethyl sulphoxide:ethanol:water (5:70:25, v/v/v) solvent mixture.
Note: if you are using something other than Everclear (190 proof--93% ethanol), for an ethanol/water mixture in this formula, you will need something that is approximately 140 proof which would be equal to 70% ethanol content. Then add 5% volume of DMSO.