Rapeseed

Traditional rapeseed contained appreciable erucic acid in its oil and glucosinolates in its meal. Both were commercial problems: the first constrained food use of the oil, the second constrained how much meal could be fed. Plant breeding from the 1970s onward produced types low in erucic acid, and then types low in both erucic acid and glucosinolates — the "double-low" or "00" types that dominate trade today.

Canola is the name given to that low-erucic, low-glucosinolate category, originating in Canada and defined against compositional criteria set out in the applicable standard. The important consequence is jurisdictional: a lot meeting those criteria is routinely called canola in Canada, the United States, and Australia, and the same seed is more often traded as double-low or 00 rapeseed in Europe. Meanwhile, high erucic acid rapeseed is still grown deliberately as a separate, segregated commodity for industrial oil use — and it is rapeseed, but it is emphatically not canola.

AgricultureID publishes no erucic acid or glucosinolate thresholds here. Those limits are set by the applicable national standard or trading contract, they differ between jurisdictions, and they are revised — the standard in force is the authority.

Crushing rapeseed yields oil and meal together. At concept level the seed is cleaned, conditioned, flaked, and pressed, and the press cake is commonly extracted further to recover remaining oil; the de-oiled solids are then processed into meal. Because the seed is small and thin-coated, rapeseed is normally crushed whole rather than dehulled, which is one reason its meal carries more fibre than dehulled soybean meal.

• Rapeseed oil — the higher-value stream, for food use and biodiesel feedstock
• Rapeseed meal — the protein stream, sold into animal feed
• Screenings and cleaning residues — removed before crushing, of low value

Lots trade on moisture, admixture, and oil content, with erucic acid and glucosinolate status specified by contract because they define which market the seed can enter. Green, heated, or mouldy seed is penalised, and green seed is a particular issue: chlorophyll retained in immature seed carries into the oil and raises refining cost, so it is a quality problem rather than only a cosmetic one.

Standards and contract descriptions are national and versioned. Meeting one describes a lot commercially; it is not a food-safety clearance and does not guarantee crush performance.

Rapeseed is small, dense-flowing, and oil-rich — a combination that makes it unforgiving in store. Small seed packs closely and resists airflow, so aeration is less effective than in a coarse cereal, and oil-bearing seed that heats develops free fatty acids that a crusher pays for. Lots often arrive above safe storage moisture and are dried promptly. Because the seed is small, it also finds every gap in handling equipment and storage structures, which makes bin preparation and sealing a practical concern.