I know this is about cooking ... but it explains the difference in starches. Since the grain in the vodka was already processed (cooked), I'm not sure if this would apply.
http://www.thekitchn.com/whats-the-d...lour-cor-84371
I also found this ....
http://www.waytogoidaho.com/whypotatograinvodka/
So it begs the question ... IF Maryellen uses Vodka in her formula, which KIND of Vodka does she use? Potato or grain?? From what I'm seeing in various places on the web, grain vodka is far more readily available than potato vodka.