I am not trying to make a tincture. I am trying to make a more potent tea... a syrup if you will (kind of like Barefoot's dewormer.) I believe that mixing it thoroughly with alcohol would make it more potent because that forces the liver to contend with it. I am not using the alcohol as a preservative but as a solvent.
The reason I am using distilled water to extract the herb is because if I boil alcohol it will evaporate.