(PD) - When you buy a bottle of wine vinegar in a supermarket, do you know what’s in it?

This question has plagued me, off and on, for 20 years. Every time I try to investigate it, I get nowhere. More about this stone-walling later.

My first assumption was that anything called “wine vinegar” started out life as wine, then was converted into an acetic acid solution to do the work that few other liquids can. The many uses of vinegar are widely known.

Vinegar can be made easily using just water and yeast; other products have been used in its manufacture, such as apple cider. Traditional wine vinegar starts with wine, white or red.

As the base for salad dressings and many other foods, it is a staple.

In the early 1990s I began investigating what was in vinegar. I did not look at the long-aged balsamic vinegars of Modena, Italy, a whole different sort of vinegar.

I started by seeking the federal definition of wine vinegar. Two months ago, decades after my casual quest, I was chatting with retired winemaker Brad Alderson and I asked him if he knew the federal definition of wine vinegar.

“There is none,” said Alderson.

That answered part of the riddle. About 15 years ago, a chemist friend told me that a lot of the “wine vinegar” sold on store shelves from large companies, with recognizable names, never started life as wine. It was called “wine vinegar,” but the “wine” came from material other than grapes.