Tartaric Acid. Tartaric acid is a naturally occurring organic acid which appears as a white crystalline solid at room temperature. Foods such as grapes, apricots, avocados, apples and sunflower seeds have all been known to have high concentrations of the acid.Alternatively, it has also been found in tamarinds which are a type of tree indigenous to tropical Africa and other warms parts of the world.ses. As mentioned above, Mexican cuisine relies heavily on the use of tartaric acid which, when combined with baking soda, acts as a leavening agent. The acid also plays a major role in wine-making where it is used during the fermentation process for acidity adjustments to make for a more palate pleasing taste.