<<Disclaimer:  Verify this information before applying it to your situation.>>

Comment from Don Kasarda, Albany, CA.

This is not medical advice, etc., etc., etc. Each of you should follow your
own inclinations, etc., etc., etc.  Some people may not tolerate vinegar,
etc., etc., etc. (Wasn't Yul Brynner great in The King and I?)

I am a research chemist specializing in the gluten proteins, but I have not
done any research on vinegar, because I don't think it would be in the least
worthwhile.

Given the above caveats, in my personal opinion, this whole vinegar thing is
simply absurd.  The only vinegar that there is the slightest reason to think
might have any harmful peptides (harmful for celiac patients) in it would be
barley malt vinegar.  My mind boggles at all those people out there
searching for gluten-free vinegar.