Olive oil is a mixture of organic compounds, making it impossible to provide a single chemical formula to represent it. The method of extracting the oil from the olives, along with the variety and ripeness of olive used, affect composition.
The bulk of olive oil is made of triglycerides, which are fats of varying carbon chain lengths. The oil contains small amounts of free fatty acids caused by the decomposition of triglycerides. Pigments are the chemicals responsible for the color of the oil. Each batch of oil has slightly different flavor compounds. In addition, there are phosphatides and sterols in the oil. Even though the finished product is filtered, there are also microscopic pieces of olive in the oil.