Yes, olive seeds, also known as pits, do contain oil and are part of the process of making olive oil, although the majority of the oil comes from the olive's flesh.
The Dual Source of Olive Oil
When olives are pressed to produce oil, oil comes from both the flesh and the seeds of the olive. While the fleshy part, or pulp, is the primary source, containing a significant 30-50% oil, the seeds also contribute, albeit to a lesser extent, holding approximately 5% oil. This means that during the initial milling process, the entire olive fruit—including the pit—is typically crushed together.
Oil Content Comparison
To illustrate the difference in oil yield, consider the following breakdown:
| Olive Component | Typical Oil Content | Contribution to Total Oil |
|---|---|---|
| Olive Flesh | 30-50% | Primary |
| Olive Seed (Pit) | 5% | Secondary |
This significant difference in oil content means that while seeds are involved, their contribution to the overall volume of olive oil, especially high-quality extra virgin olive oil, is minor compared to the pulp.
How Olive Seeds Contribute to Oil Production
The involvement of olive seeds in oil production varies slightly depending on the type of olive oil being made and the extraction method.
1. Initial Crushing for Extra Virgin Olive Oil
For most virgin and extra virgin olive oil production, whole olives are first cleaned and then fed into a mill. This mill crushes the entire fruit—skin, pulp, and pit—into a paste. The purpose of crushing the pit along with the flesh is largely practical; it's simpler and more efficient than separating the small pits before the first press. The paste then undergoes malaxation (a gentle mixing) and is subsequently pressed or centrifuged to separate the oil from the water and solids.
2. Pomace Oil Extraction
After the initial mechanical extraction of virgin olive oils, the remaining solid residue is called pomace. This pomace still contains some oil, along with crushed pits, skin, and pulp fragments. Olive pomace oil is extracted from this residue using solvents (like hexane) and heat, a process similar to how other seed oils are produced. While not considered virgin olive oil, pomace oil is a valuable product, and the oil within the crushed seeds contributes to its yield. For more details on olive oil production, you can explore resources from organizations like the International Olive Council.
Why Crushing the Whole Olive?
Several factors explain why olive pits are typically crushed with the flesh:
- Traditional Methods: Historically, whole olives were crushed using stone mills, a practice that naturally included the pits.
- Efficiency: Separating the small, hard pits from the flesh before crushing would add significant complexity and cost to the production process.
- Flavor and Antioxidants: Some research suggests that compounds from the pit, such as certain polyphenols, might contribute to the oil's flavor profile and oxidative stability, although this is a nuanced area of study.
Key Takeaways
- Direct Contribution: Olive seeds do contain oil and are crushed during the initial stages of olive oil production.
- Minor Yield: The bulk of olive oil comes from the flesh, which has a much higher oil content than the seeds.
- Processing Efficiency: Crushing the entire olive, including the pit, is a standard and efficient practice.
- Pomace Oil: Seeds contribute to the oil extracted in olive pomace oil, which is processed from the residue of the first press.
Understanding the role of the olive pit highlights the comprehensive nature of olive oil extraction, where every part of the fruit can potentially contribute to the final product.
