Vinegar or Acetic Acid comes in 5% for eating, 6% for cleaning, up to 99% (“glacial acetic acid”).  It is sold in 30% and 45% which is intended for dilution. Many vinegars are made from bases of corn or other grain; or fruits such as apple.  Depending upon individual’s need for acid and current allergy pattern (grain, yeast/mold, tree fruits), different vinegars can have different effects.