Before realizing that malt vinegar is on the not approved list for those with a gluten intolerance, I remember snacking on some delicious fair-style fries smothered in malt vinegar just over a year ago. I'd already been diagnosed with my intolerance, but I didn't have a problem. The necessary amount of time passed without a symptom. Still, I stayed away from malt vinegar just in case. No need to risk a good thing.
Until last week. It was shortly before my wisdom teeth were removed. I gave in to the craving for more fries with vinegar, knowing I would feel rough and be unable to eat for the next few days anyway. I'd already noticed that I was unintentionally losing weight already, so any chance at extra calories is good. I don't condone cheating on the diet, and trial by error (especially without medical supervision) is definitely not something I recommend. But when it's a restriction diet and you're losing weight & hungry, facing down surgery that will prevent eating solid food for a few days, sometimes you just have to give in.
I hadn't eaten anything else and doused the fries in the vinegar, so as to keep my variables controlled in the experiment. A half hour passed. 45 minutes went by. An hour and a half later, still no reaction. I made it! But that made me question the past two years. If I can eat malt vinegar, have I not really needed this (expensive and sometimes hassling) gluten free diet for the past 2+ years?!? (I've since had it again, and still no reaction.)
Upon some research, I found that malt vinegar is, indeed, made with barley, and barley does have gluten. I'm not crazy or woefully misled. I've read that malt vinegar is gluten free if distilled and isn't if brewed. I have no independent verification of this. The first reading I came across and found credible was from Peter Bronski at No Gluten, No Problems.
According to Coeliac UK:
Barley malt vinegar is made using a fermentation process. The end product only contains a trace amount of protein (and therefore gluten), which is well below the level which is safe for most people with coeliac disease. In addition, barley malt vinegar is only usually eaten in small amounts, for example, drained pickled vegetables, sauces with a meal, on chips.
Balsamic, cider, sherry, white wine and red wine vinegars are not made from barley and are also suitable for a gluten-free diet.
Nonetheless, it's still not on the approved list in the US. If you or someone you love is gluten intolerant, I don't suggest chancing it. Those of us with a gluten sensitivity - Celiac disease, intolerance, or a wheat allergy - are diverse with wide-ranging symptoms. I'm not even a fraction of the percentage of folks in this country with a gluten issue, so I'm hardly a reliable sample size.
But it did let me learn more about myself and this interesting condition. I'm sensitive enough that I cannot eat toppings off of regular pizza crust or eat fries cooked with chicken nuggets (like my uncle can), but I'm not so sensitive that I have to avoid malt vinegar. To me, that's a small victory. Fries with vinegar were part of one of my first solid meals now that my soreness from the wisdom teeth extraction is subsiding.