Vinegar Strength

When developing and following recipes in which vinegar is a prominent ingredient, cooks should take care to note not only the kind of vinegar, but also the strength, which is usually indicated on the label. In the United States, most industrially produced vinegars are adjusted to 5% acetic acid, but many wine vinegars are 7% or even stronger. Mild Japanese rice vinegars, by contrast, may be 4% (the U.S. minimum), black Chinese vinegars as little as 2%. A spoonful may thus provide half as much acetic acid as expected, or twice as much, depending on the vinegars that are called for and actually used.