Foreign Material and the Discount Column
Foreign material is what does not belong in the grain. It lands in the discount column, and standards differ by market.
Foreign material is the catch-all for things in the load that are not the grain you sold. Stones, stalks, dirt, and seeds of other plants are the obvious members. Other grains can count too, depending on the standard in force. The discount column is where that material becomes money. A buyer is paying for a commodity they can mill, feed, or ship under a spec. Material that is not that commodity takes up weight and can damage equipment or the next process. How test weight and damage join this story is covered at https://goodsandgrain.trade/grain-grading-test-weight-damage.
The definition is in the standard, not in the driveway
What counts as foreign material is written in the grade standard or the contract, not in a rule of thumb about looking dirty. One standard may separate dockage, which is removed by a set of sieves, from foreign material that stays in the work sample. Another buyer may use a single impurity number. If you argue from the wrong vocabulary, you will lose an argument you might have understood.
Ask for the definition the buyer will apply before you clean, blend, or haul. Cleaning to the wrong screen size spends money and can still miss the factor they grade.
How it shows up on the ticket
A typical ticket lists a percentage and a discount per point past an allowed level, or a rejection if the load is past a cap. The arithmetic is simple and worth doing yourself. A small percentage on a large contract is not a small amount of money. It is also not a moral judgment. It is weight you delivered that the buyer did not agree to price as sound grain.
Sometimes the discount is paired with a weight deduction. Read both lines. Paying a discount and also losing the weight is a harsher result than either line alone, and it is legitimate if the contract says so. Pretending you were charged twice by accident is how the conversation starts badly.
Sampling decides whether the number is fair
Foreign material is uneven. Dust and fines settle in pockets. A probe that misses them, or that hits only them, invents a grade. The habit of probing several depths is described at https://goodsandgrain.trade/probe-sampling-a-grain-truck. If you disagree with a result, ask for the sample method before you dispute the percentage. A retest of a bad sample repeats the bad sample.
Do not add clean grain on top of a dirty load and offer the top as the story. The probe is there to defeat that trick, and buyers remember who tried it.
Cleaning is a cost, not a feeling
Running grain through a cleaner removes some of the material and also removes some good kernels, and it takes time during harvest. Compare that cost with the discount you would pay for delivering the grain as it is. There is no universal winner. A light dockage at a mill that has its own cleaner may be cheaper to discount than to clean on the farm. A load of stones is not in that category. Stones are a rejection and a safety problem, not a negotiation.
Keep the cleaner's output identity straight if one stream is screenings. Screenings are not the original grade with a better story.
Write the factor into the sale
Name the standard, the allowed level, and the discount or rejection rule in the contract. A price that says nice grain is not a foreign-material clause. If you are exporting, assume the destination's definition can differ from the one at your local elevator. Align the words on the certificate with the words on the contract.
Standards differ by country and crop. This note does not quote a legal limit. Use the sheet your buyer actually applies.
Frequently asked questions
Is foreign material the same as dockage?
Not always. Some standards separate material removed by dockage machines from foreign material left in the sample. Ask which number is on your ticket.
Can I see the material they removed?
Ask. A serious dispute is easier to understand if you can look at the sample and the separation, not only at a percentage.
Does a good test weight cancel a foreign-material discount?
No. They are different factors. One can be fine while the other is discounted.