Effect of pH on volatility (odor) of organic acid
Acetic acid is a weak acid (pKa 4.8). Even if you neutralize it, some acetate ions will react with water to form acetic acid and hydroxide ion (hydrolysis). Since acetic acid has a quite strong smell, we are able to detect its presence in neutral acetate solutions. If you will increase pH to a high value with a strong base, the concentration of acetic acid will drop (Le Châtelier's principle).