Oilseed for Pressing. Clean Before Storage or Before the Press?

Let the harvested mixture decide

For oilseed headed to a press, clean before storage when the lot contains substantial weed seeds, pods or chaff. That trash can become a starting point for mold and heating. For other lots, cleaning can fit between storage and pressing—but seed must be cleaned before it reaches the press.

Put cleaning where it does the needed work

Look at the harvested mixture before choosing the cleaning point. A trash-heavy lot needs attention before binning, not just when the press is ready. Removing weed seeds, pods and chaff at that point keeps that material out of the stored seed. Consider two harvested canola lots. One contains substantial weed seeds, pods and chaff. Cleaning that lot before storage removes material that could contribute to heating and mold development in the stored seed. The other lot contains relatively little foreign material and is already suitable for storage based on its moisture and condition. For that lot, cleaning during transfer to the pressing bin may be practical.

The decision is not based on a universal percentage of trash. Inspect a representative sample, consider the material present and confirm that the seed is suitable for the planned storage period.

For lots without a large trash load, cleaning during transfer from the storage bin to the pressing bin is an established handling option. Penn State notes that harvest and drying equipment commonly handle more volume than cleaning equipment, making it difficult to clean every lot immediately. Start with the cleanest combine sample practical to reduce the work later.

Pre-press cleaning still has a clear job: keep unwanted material out of the extraction process. Weed seeds can interfere with extraction and add unwanted taste or chemicals to the oil. Dirt speeds wear on the press and handling components, while stones and other foreign objects can damage pressing equipment.

Match the separation to what is mixed with the seed

Metra helps choose equipment and settings for the actual material. The useful distinction is what separates the unwanted material from the oilseed you want to keep:

– VDSC vibration cleaners use screens to separate material by size, removing larger and smaller impurities from the desired seed. A standalone VDSC may be sufficient when size-based screening meets the cleaning requirement.
– ADS and ADS-CDC use controlled airflow to separate material based on aerodynamic properties, helping remove lighter unwanted fractions from useful seed. ADS-CDC also includes a cyclone dust collector.

Size screening and airflow separation address different properties of the mixture. The appropriate equipment and settings depend on the material and the result required before pressing.

In a sample demonstration, look for unwanted material still traveling with the cleaned oilseed and useful seed leaving with the removed material. The first shows what remains to be cleaned; the second shows seed being diverted from the pressing supply.

Cleaning does not replace moisture management

Cleanliness and moisture are separate requirements. Oilseed must be dry enough for its intended storage period and suitable for the oil press that will process it. Those moisture targets may differ. Penn State's oilseed guidance lists typical pressing moisture ranges of 7–9% for canola and sunflower and 9–11% for soybeans. These are crop-specific pressing guidelines, not universal long-term storage limits or guaranteed settings for every press. Confirm the appropriate requirements for the crop, storage conditions and pressing equipment.

Stored oilseed also needs monitoring. As outside temperatures fall in autumn, Penn State recommends checking the seed and container weekly for condensation. When moisture appears, aeration helps cool the seed and remove that moisture. Checks can be spaced farther apart after the seed reaches winter temperatures.

Start with your oilseed and its unwanted material

To discuss cleaning before binning or before pressing, contact Metra at [info@graincleaner.com](mailto:info@graincleaner.com) to arrange a free grain sample test. The manager will help match the equipment and settings to your mixture and agree on sample quantity and shipping or demonstration arrangements.