I thought white vinegar was from wheat (according to my friend who has two sons with celiac) but that the distillation process rendered it safe. The problem is that my DS is intolerant to wheat and gliadin, not gluten, so I don't know if it's still safe or not. I had been using rice vinegar, but he tested positive for rice, and apple. I have tarragon vinegar but know nothing about that, so I'll have to figure that one out. I need vinegar to make my own ketchup (without cane sugar or onion) so I was trying to figure this out.
I think I've also run into 1 or 2 false negatives (corn and potatoes, that DS had been off of before the test) on the ALCAT test.