Re: What constitutes the vinegar flavor in 'salt-and-vinegar' flavored chips?

Salt & vinegar potato chips taste like vinegar because they share an ingredient with vinegar, acetic acid. However there's a bit more to it than that; straight acetic acid (glacial) is very strong and unfit for human consumption. So, the chip makers buffer it to bring the pH up to ingestible levels by also adding its salt, sodium acetate. As an aside, the traditional vinegar used with chips is malt vinegar, which has a distinctive flavor beyond being acetic, so most potato chip manufacturers include other flavors to approximate maltiness. Next time you eat a bag of salt & vinegar chips, check the label; or even better, compare those ingredients to the ingredients listed on a bag of plain chips.