Actually malting rooms use smoke to stop just before sprouting, the malt-master makes sure he catches that before, using TCM terms, the sexual energy is lost..
They use a hightly scientific method to judge when the barley is ready.. same method my Grandma used to catch beans just before they sprouted.
You soak a small amount an hour before the rest when they sprout you stop the others from spouting.. you can add that to the things your Great-grandma knew and we are clueless about..