How to Reduce Oil Loss During Screw Pressing

To reduce oil loss during screw pressing, control the feed material, preparation, moisture, temperature, machine settings, and cake discharge. You also need to measure oil and cake using the same conditions. A higher oil content in the raw seed does not automatically mean that the press will produce the same oil output every time.

At Fude Machinery, we recommend checking the complete pressing process before changing the machine. Many oil loss problems begin before the seeds enter the press. Other problems come from worn parts, unstable feeding, poor filtration, or incomplete records.

This guide explains where oil loss can occur and what you can check before making equipment adjustments.

What Does Oil Loss Mean During Pressing?

Oil loss during screw pressing is not one single measurement. You should separate the oil remaining in the cake, oil retained in solids, oil held inside equipment, and differences caused by measurement methods.

The following terms describe different parts of the process:

Term	Meaning
Raw material oil content	The total oil naturally present in the seed or kernel
Collected oil	Oil recovered at the collection point used for measurement
Oil in press cake	Oil that remains in the solid cake after pressing
Oil in fine solids	Oil held in particles removed during settling or filtration
Retained oil	Oil remaining inside the press, pipes, tanks, or filter
Handling loss	Oil lost through leaks, spills, or uncontrolled transfer
Measurement difference	An apparent loss caused by different weighing points or time periods

You cannot calculate true extraction performance from collected oil alone unless the feed basis, test period, and collection point are clearly defined.

For example, oil collected directly below the press may include fine particles and moisture. Oil weighed after settling or filtration may have a different mass. These results should not be compared without explaining the difference.

Start With the Raw Material

The press can only work consistently when the incoming material is consistent. Seed variety, storage condition, moisture, impurities, and damage can all affect pressing behavior.

Before changing the machine, inspect the material entering the production line.

Check:

• Oilseed type and variety.
• Supplier or batch.
• Storage time and conditions.
• Visible mold, insects, stones, and metal.
• Broken or damaged seeds.
• Moisture information, when available.
• Whether the material has already been cleaned or shelled.

If your business processes several oilseeds, record each material separately. Peanuts, sunflower seeds, sesame, rapeseed, soybeans, and palm kernels do not behave in exactly the same way.

A machine setting that works for one material may cause unstable feeding or a high oil content in the cake when used with another material.

Improve Cleaning Before Pressing

Cleaning protects the press and improves the consistency of the feed. Stones, metal, soil, and other foreign matter can damage working parts or disrupt the pressing chamber.

Cleaning also reduces the amount of unwanted material entering the oil stream. This can make later settling and filtration easier.

A suitable cleaning arrangement may include:

• Screening.
• Air separation.
• Destoning.
• Magnetic separation.
• Manual inspection for unusual materials.

The correct equipment depends on the raw material and the contamination risk. Do not assume that one screen can remove every type of foreign matter.

Poor cleaning may create several problems:

• Uneven feeding.
• Damage to the screw or press cage.
• More solid particles in the crude oil.
• Higher filter loading.
• Unexpected production stops.
• More oil retained in separated solids.

You can review the available oilseed preparation and oil processing equipment when planning the complete process around the press.

Match Shelling and Size Preparation to the Material

Some oilseeds require shelling or dehulling before pressing. Others are processed as whole seeds or kernels. The correct preparation depends on the material and the intended product.

The goal is to present the press with a feed condition that it can process steadily.

If the material is too large, too hard, or poorly prepared, the press may need more adjustment. If it is over-crushed, the feed may become difficult to control and may create more fine particles.

Before selecting or adjusting size preparation equipment, confirm:

• Whether shelling is needed.
• The expected shell-to-kernel ratio.
• The desired particle size.
• Whether crushing creates excessive powder.
• How the prepared material will be stored before pressing.
• Whether the preparation capacity matches the press capacity.

Control Moisture Before Pressing

Moisture affects how oilseeds move, compress, and release oil inside the press. Material that is too wet may produce a soft cake and unstable discharge. Material that is too dry may create excessive friction, poor feeding, or a cake that is difficult to form.

There is no single moisture value that suits every oilseed and machine. The correct condition should be confirmed through technical testing and the equipment instructions.

We recommend recording:

• The moisture result.
• The sampling location.
• The measurement method.
• The batch identity.
• Any drying, steaming, or conditioning performed.
• The time between preparation and pressing.

If the incoming material changes after storage, measure it again before blaming the press for a yield change.

A moisture meter reading should not be treated as a universal operating limit unless the method and material are known. Use comparable measurements when reviewing different batches.

Use Temperature for Process Control

Temperature can affect oil viscosity, material plasticity, and the way the cake forms. In hot pressing, heating or cooking may be part of the preparation process. In cold pressing, the process must be managed to control heat generated by friction and compression.

A heater setting is not the same as the temperature of the oil leaving the press.

When monitoring temperature, record:

• Where the temperature is measured.
• Which instrument is used.
• When the reading is taken.
• Whether the reading is for the feed, press surface, or collected oil.
• Whether the machine is stable or still starting up.

Avoid changing temperature and other settings at the same time. If several factors change together, it becomes difficult to identify what caused the result.

If you intend to sell oil with a temperature-related processing claim, confirm the applicable requirements for your market and record the actual process conditions. The machine name alone does not establish whether the finished oil meets a particular claim.

Keep Feeding Stable

Unstable feeding is a common reason for inconsistent pressing results. When the press receives material too quickly, too slowly, or in irregular batches, the pressure and cake discharge can change.

Check the path from the preparation equipment to the press:

• Is the hopper receiving material continuously?
• Does the feeder bridge or block?
• Is the material flowing evenly?
• Does the operator add material by hand?
• Are there sudden changes between full and empty feeding?
• Does the feed rate match the press setting?

A stable feed helps the screw maintain a more consistent compression pattern. It also makes your measurements easier to compare.

If the press is designed for a feeder, use the specified arrangement or confirm any alternative with the supplier. A larger hopper does not automatically create a stable feed.

Check the Screw Press Settings

The correct settings depend on the equipment model and the material. These may include feed rate, screw speed, press adjustment, temperature control, and cake outlet settings.

Change one operating variable at a time and record the result.

A useful adjustment record includes:

Setting or Observation	What to Record
Material	Oilseed and batch identity
Feed condition	Moisture, preparation, and temperature
Feed rate	Measured or controlled rate
Screw speed	Setting or measured speed, where applicable
Temperature	Measurement point and reading
Cake discharge	Thickness, shape, and stability
Oil collection	Collection point and weighing time
Press interruptions	Blockages, stops, and adjustments
Result	Oil and cake measurements using the same basis

Do not treat a thicker cake or darker oil as proof of higher extraction. These observations may indicate a process change, but they require consistent measurements.

When comparing machines, confirm whether the quoted capacity and oil output were measured under similar material and operating conditions.

Inspect Wear Parts Regularly

Worn parts can change the pressure and material movement inside the pressing chamber. A worn screw, press cage, or cake outlet component may affect both oil separation and cake formation.

The parts that require inspection depend on the machine design. Ask for the operating manual and recommended inspection schedule.

Possible warning signs include:

• A gradual change in cake thickness.
• More frequent blockages.
• Lower collected oil under similar feed conditions.
• Increased solid particles in the crude oil.
• Unusual vibration or noise.
• Longer startup or adjustment time.
• Visible wear on working surfaces.

Do not replace parts based only on appearance. Compare the observed condition with the manufacturer’s criteria and the machine’s operating records.

The oil press maintenance guide can be used as a starting point for routine inspection, but the actual maintenance procedure should follow the manual for your model.

Manage Cake Discharge

The cake outlet controls how the pressed material leaves the chamber. If the outlet is too open, the material may pass through with more residual oil. If it is too restricted, the press may experience excess pressure, heat, or unstable operation.

The correct adjustment depends on the oilseed and machine design. Ask the supplier how to identify a stable cake condition for your material.

Record:

• Cake thickness.
• Cake shape.
• Cake moisture.
• Breakage or powder.
• Visible oil on the surface.
• Discharge stability.
• Changes after adjustment.

A cake that looks dry may still contain significant oil. If residual oil is an important performance measure, use an appropriate laboratory method rather than visual inspection alone.

Do not increase pressure without checking machine limits. Excessive adjustment can damage components and create safety risks.

Reduce Oil Retained in Solids and Filters

Oil can leave the main product stream with fine solids, filter cake, or other separated material.

Good filtration should improve oil clarity without creating uncontrolled oil retention.

Review:

• The filter type and operating capacity.
• Filter cloth or screen condition.
• Cleaning frequency.
• Time allowed for draining.
• Oil remaining in filter cake.
• Storage and recovery of separated material.
• Whether the same measurement basis is used for each batch.

A filter may remove solids while retaining some oil. This does not automatically mean the filter is unsuitable. The decision should consider oil clarity, product requirements, oil retention, cleaning time, and the value of recovered oil.

You can compare the pressing process with the edible oil refining equipment needed when the crude oil requires treatment beyond mechanical filtration.

Measure Oil Loss With a Clear Method

Use the same measurement boundary when comparing batches. Weighing crude oil at the press inlet and finished oil after filtration may include several process stages between the two points.

For a defined test, you can calculate:

Collected oil yield (%) = collected oil mass ÷ feed material mass × 100

This calculation describes collected oil on the selected feed basis. It does not automatically equal total oil recovery.

To investigate oil remaining in the cake, you need additional information about:

• The oil content of the raw material.
• The oil content of the cake.
• Moisture and reporting basis.
• Oil in fine solids and filter residue.
• Retained oil inside equipment.
• Samples removed during the test.

A simple record can include:

Record	Example of What to Note
Feed material	Oilseed, batch, and preparation
Feed mass	Weight entering the press
Running time	Measured operating period
Collected oil	Weight and collection point
Cake	Weight and sample reference
Filtration	Method and time before weighing
Retained material	Oil left in pipes, tank, or filter
Result limits	Unmeasured items and assumptions

Do not describe every difference between feed mass and collected oil as avoidable oil loss.

Use a Short, Controlled Test

If you are testing a new setting or comparing equipment, keep the test conditions stable.

A useful test should record:

1. Oilseed type and batch.
2. Preparation method.
3. Moisture or other available analysis.
4. Machine model and configuration.
5. Feed rate.
6. Running time.
7. Temperature measurement.
8. Collected oil and cake weights.
9. Interruptions and adjustments.
10. Test limitations.

Run a sufficient period to reach stable operation before recording the main result. A short startup period may not represent normal production.

If the result will be used in a purchase agreement, define the acceptance method in writing. State the feed material, preparation, operating conditions, measurement method, and responsible people.

For a complete equipment discussion, you can review the oil press product range and prepare your material and capacity information before requesting a quotation.

Common Questions About Screw Press Oil Loss

Does More Oil in the Cake Always Mean the Machine Is Faulty?

No. The result may be affected by the oilseed, moisture, preparation, feed rate, temperature, wear parts, and cake outlet. Compare the same material and conditions before judging the machine.

Does a Higher Temperature Always Improve Oil Recovery?

No. Temperature can affect oil flow and pressing behavior, but excessive heat may change oil quality and create other process problems. Use the operating conditions confirmed for the material and machine.

Can One Setting Work for All Oilseeds?

Usually, you should confirm settings for each material. Different oilseeds have different physical properties and preparation needs. Record the conditions separately when changing raw materials.

Should I Increase Pressure When the Cake Contains More Oil?

Do not increase pressure without checking the equipment instructions and other process conditions. First review feed preparation, moisture, feeding stability, wear parts, and the cake outlet.

Does Filtration Remove Oil From the Product?

Filtration removes suspended solids, but some oil may remain in the separated material or filter. Check the filter capacity, draining procedure, and residue handling if this affects your production result.

How Can I Compare Two Screw Oil Presses?

Use the same oilseed, preparation method, feed basis, running period, collection stage, and measurement method. Ask each supplier to state the conditions behind its capacity and yield figures.

Improve the Process Before Changing the Machine

Reducing oil loss during screw pressing begins with consistent raw material, suitable preparation, stable feeding, controlled operation, good maintenance, and clear measurement.

At Fude Machinery, we recommend reviewing the complete process around the press rather than judging performance from one number. A clear test record can show whether the main issue comes from material preparation, machine settings, equipment wear, filtration, or measurement boundaries.

Send us your oilseed type, daily processing target, feed condition, and current pressing problem. We can then discuss the machine configuration and supporting equipment needed for your production plan.