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Benefits of Plastic Decanting Tanks In The Olive Oil Production Process

Olive production is a delicate process that has been perfected over thousands of years. The journey from olive to gourmet olives and oil involves several critical steps, including harvesting, crushing, managing, and finally, decanting. Each stage is crucial in ensuring the quality and purity of the olive fruit and oil. We will explore these steps in detail, with a particular focus on the decanting process using plastic decanting tanks manufactured by RotoTank™. These robust, food-grade plastic tanks offer numerous advantages over traditional steel tanks, including cost-effectiveness and ease of use.

The Olive Oil Production Process

  1. Harvesting

The production of high-quality olives begins with the careful harvesting of olives. The timing of the harvest is critical, as it affects the flavour, aroma, and overall quality of the oil. Olives are typically harvested when they are just beginning to ripen, as this stage it yields oil with the best balance of flavour and nutritional properties. Preserved olives need to be cured. This curing process also takes place within these decant-tanks.

Olives can be harvested by hand or using mechanical methods. Hand-picking is more labour-intensive but ensures that the olives remain undamaged, preserving their quality. Mechanical harvesters, on the other hand, are faster and more efficient, making them suitable for large-scale operations.

2. Process of Oil Production

Once harvested, the olives are quickly transported to the mill to begin the crushing process. The speed of this transition is crucial to prevent the olives from fermenting or deteriorating, which could negatively impact the oil’s quality.

The crushing process involves breaking the olives down into a paste. This is traditionally done using large stone mills, but modern methods often employ hammer mills or disk crushers. The objective is to rupture the olive cells, releasing the oil contained within. This paste includes olive pulp, skins, pits, and a small amount of water.

After crushing, the olive paste undergoes malaxing, a process of slowly churning the paste for 20 to 40 minutes. Malaxing allows the small oil droplets to combine into larger droplets, making it easier to separate the oil from the water and solids. This step is performed at controlled temperatures to prevent the degradation of the oil’s delicate flavours and aromas.

The next step is the separation of oil from the olive paste. This is typically done using a centrifuge, which spins the paste at high speeds to separate the oil, water, and solids. The result is a mixture of oil and water, which requires further processing to achieve pure olive oil.

During the decanting process the watery oil mixture is put into RotoTank decant-tanks which allows the oil to settle and separate from any remaining water and sediment. This step is crucial for producing high-quality olive oil, as it removes impurities that can affect the oil’s taste, clarity, and shelf life. Decanting can be done using traditional methods, such as gravity settling in stainless steel tanks, or more modern methods involving plastic decanting tanks.

  1. Maturing Gourmet Preserved Olives


After harvesting olives, the olives are washed to remove any dirt or debris. To allow the brine or marinade to penetrate the olives, they are cracked, slit, or sometimes soaked in lye (a traditional method used in some regions). The olives are soaked in RotoTank decant-tanks making it easier to removed cured olives later without damaging or handing it too much.

There are several methods for curing olives, including:

   – Brine-curing: Olives are soaked in a saltwater brine solution for several weeks to several months. The brine is typically made with water, salt, and sometimes vinegar and herbs.

– Water-curing: Olives are soaked in water, changing the water daily to remove bitterness. This method can take several weeks.

   – Lye-curing: Olives are soaked in a lye solution to remove bitterness and then rinsed thoroughly before brining or curing.

After curing, olives can be flavoured by marinating them in oil with herbs, garlic, citrus peel, or spices. This process can take a few days to several weeks to infuse the olives with flavour.


With all these forms of curing and flavouring, especially water curing a RotoTank decant-tank has the benefit of allowing the complete drainage of all liquid without handling or disturbing the olives in the process. No residue is left since 100% drainage is facilitated.

Once the olives have been cured and flavoured to the desired taste, they are packed in jars or containers with oil or brine for preservation.

The exact process can vary depending on the type of olives being preserved and the regional or cultural preferences. Each olive variety and preparation method can result in unique flavours and textures.

Advantages of Plastic Decanting Tanks by Rototank

RotoTank offers a range of plastic decanting tanks that are specifically designed for olive oil storage and decanting. These tanks provide several advantages over traditional steel tanks:


  1. Cost-Effectiveness: Plastic tanks are significantly cheaper to produce and maintain than steel tanks. This cost saving is especially beneficial for small-scale producers and those just starting in the olive oil industry.
  2. Durability: RotoTank’s plastic tanks are robust and durable, designed to withstand the rigors of long-term storage without compromising the quality of the olive oil. The tanks are made from high-quality, food-grade plastic (polymer) that is resistant to corrosion and impact.
  3. Ease of Use: Plastic tanks are lighter and easier to manage than steel tanks. This makes them easier to clean, transport, and manage, especially in smaller production facilities.
  4. Specific design: The olive decant-tank is specifically designed to allow the soaking medium (brine) to fill the tank completely un into its fluke. There are no cavities where air can collect and facilitate bacteria growth. The floating olives can be dunked below with a floating plate, which prevents the top layer of olives in the fluke to have any contact with air.
  5. Food Safety: The food-grade plastic used in RotoTank’s decanting tanks ensures that the olives remain free from contaminants.
  6. Efficient Sediment Collection: The design of RotoTank’s decanting tanks allows sediment to gather at the base efficiently. The tanks are easy to drain, enabling producers to remove sediment-laden fluids to drain first. This results in a cleaner, higher-quality final product.

  1. Steps in the Decanting Process for Olive Oil

    1. Initial Settling

    After separation, the mixture of oil and water is transferred into the plastic decanting tanks. Here, the oil is allowed to settle for a period, typically ranging from a few days to several weeks. During this time, any remaining water and sediment gradually settle at the bottom of the tank.

    1. First Drain

    The design of RotoTank’s decanting tanks allows for an easy and efficient draining process. The first drain involves removing the sediment-laden oil from the bottom of the tank. This step ensures that most impurities are removed early in the process, leaving the clearer oil to settle further.

  1. Secondary Settling

After the initial draining, the oil is allowed to settle again. This secondary settling period allows any remaining fine particles and water droplets to continue settling out of the oil. The longer the oil is allowed to settle, the clearer and purer it becomes.

  1. Final Drain and Bottling

Once the oil has sufficiently settled, a final drain is performed to remove the clear, high-quality olive oil from the tank. This oil is then ready for bottling. The use of glass bottles is preferred for olive oil, as it protects the oil from light and air, which can degrade its quality.

The Benefits of Proper Decanting

Proper decanting is essential for producing high-quality olive oil. It ensures that the final product is free from impurities, has a longer shelf life, and maintains its delicate Flavors and aromas. Using plastic decanting tanks by RotoTank enhances this process by providing a cost-effective, durable, and food-safe solution for olive oil producers.

  1. Improved Quality

By efficiently removing water and sediment, the decanting process ensures that the olive oil is pure and free from impurities. This results in a better-tasting, higher-quality product that meets consumer expectations.

  1. Extended Shelf Life

Removing impurities and water from the olive oil helps to extend its shelf life. Water and sediment can promote the growth of microorganisms and lead to the degradation of the oil. Proper decanting minimizes these risks, allowing the oil to be stored for longer periods without losing its quality.

  1. Enhanced Flavour and Aroma

Olive oil’s flavour and aroma are delicate and can be easily compromised by impurities. By thoroughly decanting the oil, producers can preserve these qualities, ensuring that the final product retains the characteristic taste and smell that consumers love. The materials which the RotoTank decant-tanks are made of and taste and smell neutral and will not affect the flavour of the product whatsoever.


The production of high-quality preserved olives and oil involves several critical steps, from harvesting and crushing to malaxing and decanting. Decanting is essential for ensuring the purity and quality of the final product. Plastic decanting tanks by RotoTank offer numerous advantages over traditional steel tanks, including cost-effectiveness, durability, ease of use, and food safety.

By allowing for efficient sediment collection and easy draining, these tanks help producers achieve the highest standards of preserved olives and olive oil quality. As a result, consumers can enjoy gourmet olives and olive oil that is pure, flavourful, and long-lasting. Embracing modern solutions like RotoTank’s plastic decanting tanks is a smart move for any olive oil or preserved olive producer looking to enhance their production process and deliver the best possible product to the market.

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