Soda ash is indeed a capricious thing. I can make the same recipe using the same ingredients with the same full gel and one will have ash, and one won't. No rhyme or reason. Much easier to learn quick ways to deal with it(if it bothers you), than to stress out about what you did or did not do wrong. I figure if I am giving a new person my soap, I will remove it from those bars, but otherwise I am not going to worry about it. It comes off on first use anyway.