Ever hear of malt vinegar? Thats probably what you made. In the United Kingdom, salt and malt vinegar is a traditional seasoning for chips and crisps.
Vinegar is made from the fermentation of a variety of sources mainly containing carbohydrates and sugars. Ethanol is first produced as a result of fermentation of sugars, ethanol is then oxidized to acetic acid by the acetic acid bacteria (AAB). The ethanol may be derived from many different sources, including wine, cider, beer, or fermented fruit juice, or it may be made synthetically from natural gas and petroleum derivatives.