However, the standard white vinegar may not be quite strong enough to get rid of all the weeds you want to banish from your yard. Instead, there is herbicidal vinegar, which contains 10% to 30% acetic acid. Compare this to distilled white vinegar which contains about 5% of the acid. Acetic acid is the byproduct of two-stage fermentation, and it's what makes vinegar smell like it does. In a bottle of white vinegar, about 95% of it is water; for cleaning vinegar (which shouldn't be used for cooking), it's 94% water.