Olive oil is extracted entirely from the olive tree's fruit. Neither oil is derived by solvents or refinement processes nor combined with other oils. Mediterranean diets value olive oil for its versatility and numerous health benefits. Harvesting olives at the right time, crushing them into a paste, separating solids from liquid components, and further separating oil from vegetable water have been the basic steps for making olive oil for thousands of years. Olive oil extraction determines its flavour and quality. In addition to increasing quality and productivity, the mechanical process has undergone numerous refinements and changes.
Keep reading to learn the step-by-step process involved in olive oil production.
Did You Know? Spain is the world's largest olive oil producer and exporter, followed by Italy, Morocco, and Portugal.
What Is Olive Oil Made Of?
Olive oil can transform an ordinary meal into something extraordinary. Olive is the name of a fruit, and olive oil is the juice of this fruit in its purest and most natural form. You have to crush and press olives to get drip-free oil. Most manufacturers don't follow that simple process.
About Cultivating Olive Trees
Cultivating olive trees requires dedication and passion. Fertilisation, pruning, defence, and harvesting are some phases repeated every olive-growing season. These phases are crucial for high-quality olive oil. Oil was extracted in ancient times by compressing drupes in stone mortars or crucibles obtained from rocks to rupture them. Since the 4th century BC, rotating wheels have been used with stone and wooden bases. They have a wooden axis inserted in the centre to allow humans and animals to move. Olive oil processing involves breaking down the fruit and transfor ming it into a paste to extract the juice or oil. Sansa is the solid residue left after chemical extraction, which you can use to remove the oil further.
How is Olive Oil Made - Extraction Process Explained
Olive oil extraction involves extracting oil from olive drupes, a process known as olive oil extraction. During olive oil extraction, manufacturers separate oil from the other contents of the fruit (solid material and vegetative extract liquid). It is possible to achieve this partition physically since oil and water do not mix. The process differs from extracting other oils using chemical solvents, like hexane. During extraction, the olives first undergo a washing process to remove contaminants, especially soil, that can cause a specific flavour effect called "soil taste".
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Olive Oil-Making Process
The olive oil manufacturing process traditionally consists of stages ending with olive oil packaging. Optimising each step of the olive oil production process is essential to achieve the highest quality and characteristics. As you read on, learn about the stages of the olive oil production process, from the harvest to the end product.
Step 1: Harvesting and Transmitting Process
A key to producing good quality olive oil is picking olives at the proper maturity stage with healthy-looking, good-sized, and coloured fruit at the right time. Initially, all olives are green, then gradually become rosy, and finally black. The producer may use a combination of all three depending on the type of oil they make. Traditionally picking olives involves hand labour. More and more growers use modern machinery to harvest their crops today. Then they transfer the olives directly to our state-of-the-art olive oil mill within a few hours after placing them in plastic crates.
Step 2: Olive Cleaning
As a second step, clean the olives and remove the debris left on them, including leaves, stems, and twigs. You should remove pesticides, dirt, and other contaminants from olives with water. In addition to damaging hammer mills, rocks and sand will quickly break centrifugal decanters or oil separators, reducing their lifespan from 25 to as little as five years. Seeing what you can create with olives in the bins can be entertaining and unique. The airflow or blower removes light contaminants, and the water bath sinks heavy objects.
Step 3: Make a Paste by Grinding the Olives
You can make a homogeneous pulp by grinding olives and their stones. An upright granite block rests perpendicularly on a granite millstone that sits horizontally in a stone mill. Various types of mills are used for this purpose, including metal and hammer mills. Water is added to frozen or dehydrated olives when processed.
Step 4: Malaxing
Malaxation is the next step. Milled olives are churned or mixed gradually for 20 to 40 minutes during malaxation. During the churning process, fewer oil droplets are released, making it easier to separate them. There is a relationship between temperature, mixing time, and oil yield. Olive oil is cold-pressed at 22-25 degrees °C/71.6 - 77°F per variety under controlled atmospheric pressure (cold pressing) to maintain the highest quality.
By using this process, you can achieve the following three goals:
- Grind the olives well to ensure stability.
- The largest olive oil droplets will form by joining olive drops together for an adequate amount of time.
- A fruit enzyme allows the oil to produce some aromas and flavours.
Step 5: Removing the Oil from the Solids and Vegetable Water
You must separate the oil from the rest of the olive components in the next step. You could do the process using presses (hence the terms first press and cold press, which have become obsolete), but it is now done by centrifugation, except in older facilities. The oil, the water, and the solids are separated in some centrifuges known as three-phase centrifuges. The wet paste is separated from the oil in two-phase centrifuges. The oil from the first centrifuge is usually further processed by a second centrifuge that rotates faster. This is to eliminate any remaining solids and water. Gravity separates the oil, if needed, after storing it in tanks or barrels. Racking is the process of storing oil. You can also filter the oil if you wish.
Step 6: Residual Oil Extraction
The residual oil is removed from the high-loaded wastewater from the three-phase decanter by a vibrating monitor and a centrifuge. After dual centrifugation, a collection tank and eccentric worm pumps pump the oil into underground or surface tanks. There is still about 4% olive oil in the solid waste from oil extraction using a continuous three-phase decanter. A dual-phase decanting process results in a liquid-solid mixture with an oil content of 2.5% to 3.5%. Specialised plants use solvent extraction for this purpose. A solvent, like hexane, extracts waste after drying. As a concentrated feed, you can use these residues as dry residues. Some extraction plants separate the stones from the pulp after extraction and use them as fuel to heat their dryers. In addition to being sold as fertiliser, pulp can be used as animal feed. Occasionally, solid waste from oil mills is directly used as fuel to heat water.
Step 7: Storing the Oil and Packaging
Each olive oil plant has an organised packaging department with all the required certifications in its facilities. To ensure olive oil purity, they conduct chemical analyses after its formation. They then store the olive oil in stainless steel containers based on their variety and quality. They use nitrogen to fill any tank space to prevent it from becoming bare. Lastly, manufacturers fill olive oil bottles or tins with machines that automate the bottling process. It is ready to be shipped worldwide for the customers to enjoy, and the final product is sealed, labelled, and marked with, among other things, the batch number and the expiration date.
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Producing One Litre of Olive Oil
It takes four to five kilograms of olives to produce a litre of olive oil. Based on the weight of the olives processed to obtain oil, the average yield is approximately 18% to 24%. The proportion varies depending on climate, harvest time, and olive variety, although this is a general rule. In early harvest oils, for example, this proportion is much lower; in this case, 8 kilos of early olives are needed to produce one litre of olive oil.
Conclusion
Olive oil is made from ripe olives. The production of olive oil comprises six steps:
1. Harvesting, 2. Processing, 3. Malaxation, 4. Pressing, 5. Refining, and 6. Bottling.
Once a year, during the harvesting season, olives are picked by hand or by machine. After separating them from leaves and branches, machines crush and mill olives into a thick paste. Manufacturers churn the mixture slowly to extract oil drops from the remaining mix. Centrifuges or mechanical presses separate olive oil from water and pulp. Then olive oil is bottled, packaged, and shipped to distributors or consumers.
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