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

The Knudsen & Sons, Inc., Cindy Schroeder, at (916)899-5000 wrote that
the Natural flavors in their  product ,Lemon Genger Echinacea juice,  is
derivated from fruit juices, vegetables, spices, and herbs, or other
plant material or fermentation products. The flavor components are
blended is a base of grain distilled alcohol.  Alcohol is a distilled
product, so it does not contain protein and is, therefore, gluten free.

I think this may be the same discussion as the distilled vinegar.  I am
not going to try this unless someone can confirm  it as gluten free.