Mix-ups Between Oilseed and Grain Cargoes
A bin or truck that last carried oilseed can spoil the next grain cargo. The mix-up is physical and contractual.
Oilseeds and cereal grains share elevators, trucks, and sometimes ships. They should not share a careless bin. Soybeans, canola, and sunflower seed leave oil and broken seed behind. The next cargo of wheat or corn can pick up admixture, odor, or a quality complaint that has nothing to do with the field it grew in. The reverse is also true. A food oilseed loaded on top of sour grain inherits the smell. Canola's place in that oilseed family is described at https://goodsandgrain.trade/canola-rapeseed-oil-and-meal. The handling system that makes these mix-ups easy is the bulk system, sketched at https://goodsandgrain.trade/sacks-to-bulk-grain-handling.
Admixture is a grade factor
A few percent of soybeans in a wheat tender is foreign material or a class problem, depending on the standard. It is not explained away by saying the pit was busy. Buyers count what is in the sample. Foreign-material discounts are the general mechanism, at https://goodsandgrain.trade/foreign-material-discounts. Oilseed pieces can be large enough to see and still be missed if you only glance at the top of the truck. Sample the way the grade will be sampled, not the way that flatters the bin.
Identity crops are less forgiving than feed. A durum buyer or a milling-wheat buyer did not buy a soybean blend. Class mistakes of that seriousness are discussed for wheat at https://goodsandgrain.trade/durum-versus-bread-wheat.
Residue and the truck you did not sweep
Oil from broken seed sticks to floors, belts, and tarp corners. Grain loaded next can carry a stale or sour smell that a food buyer will reject even when the admixture percentage looks small. Sweep the box. The loading checklist for farm trucks is the right moment, at https://goodsandgrain.trade/farm-truck-loading-checklist. At an elevator, a leg that ran oilseed and then ran wheat without a clean-out is the same mistake at a larger scale.
Ask what the bin held last if you are storing for someone else. A cheap bin that last held a different commodity is not cheap if it ruins the lot.
Contracts that assume purity
Many grain contracts are silent because they assume the commodity named is the commodity loaded. Silence does not forgive a mixed pit. If you intentionally handle both, write a clean-out step into the receiving plan and refuse loads that are already mixed. Once soybeans and corn are in the same truck, separating them may cost more than the load is worth. Turning the truck around at the farm is cheaper.
On export documents, the description has to match the commodity you actually loaded. Calling a mixed lot by the higher-priced name is a false invoice. Descriptions that drift are one of the paperwork failures listed at https://goodsandgrain.trade/paperwork-mistakes-that-delay-cargo.
Ships and containers remember
A hold that carried seed, or a container that carried meal, needs a look before a food grain goes in. A surveyor who will inspect rather than only sign is worth booking before loading, not after a complaint. Sampling plans for bulk and bags are at https://goodsandgrain.trade/sampling-bags-versus-bulk. If the previous cargo was a poor match, say so before you load. Discovering it from a destination complaint is the expensive version.
Separate the streams on purpose
Give oilseed and grain different bins when you can, different clean-out steps when you cannot, and different contract descriptions always. The mix-up is rarely dramatic. It is a door left open between two commodities that the grade sheet treats as strangers. Treat them as strangers before the sample does.
Frequently asked questions
Is a little soybean in the corn just dockage?
It is at least foreign material, and it may breach a purity the buyer expected. Ask for the tolerance before you call it minor.
Will a smell leave if the grain sits?
Do not count on time to fix an oilseed odor. Keep the lot apart and tell the buyer before you ship it as food grain.
Can the same leg run both crops?
Many houses do, with a clean-out between them. Skipping the clean-out is how the next grade inherits the last commodity.