Joshsmom, that’s interesting - my DS can also tolerate soy flour and soy sauce, but no other forms of soy. And strangely he was allergic to milk when he was little, and grew up on soy milk, soy cheese and tofu. Then somewhere along the line he lost the milk allergy and became allergic to soy.
Anyhoo, I usually make my own, but honestly can’t remember the last time I made it.