In chemistry, pH is a scale used to measure the relative acidity or basicity of an aqueous solution-that is, one in which a solute (salt, sugar, etc.) is dissolved in water. Because only aqueous solutions have pH levels, vegetable oil has no pH value. Likewise, other oils such as animal and petrochemical oils also have no pH value.
Acidity, as it relates to flavor, should not be confused with an oil's fatty acid content. Fatty acids are organic molecules often found in foods, including vegetable oils. Olive oil consists primarily of oleic acid, with smaller quantities of palmitoleic acid and linoleic acid. The purest olive oils have a very low volume (under 2 percent) of free fatty acids. These acids, again, have nothing to do with pH levels.