Sampling grain properly: intake, store and dispute

One scoop off the top of one trailer tells you almost nothing about a heap. Moisture swings through the day — grain cut in morning dew can run two points wetter than the 3pm loads off the same field — and quality varies field to field, headland to middle, load to load. A single sample is a single data point wearing the costume of an answer. The farms that know what's in their sheds, and win the arguments when a buyer's results disagree, are the ones sampling every load, properly, and keeping the evidence.

The good news: done right, it's a two-minute job per trailer.

Sampling a load so the sample means something

The principle is the same whether it's a trailer at the pad or a heap in a shed: many small draws, mixed, then reduced to a testable sub-sample.

• Spear several spots per load — a sampling spear pushed in at four or five points across the trailer, at depth, not just skimmed off the surface. The top of a load is the last grain in and the first to catch weather on the road home.
• Mix the draws in a bucket, then take your working sample from the mix. This averages out the wet corner and the bold middle.
• Do it at intake, against the load record. Sample as the trailer is weighed or tipped, and write the results against that load — field, time, moisture. A reading that isn't recorded against something is trivia by the weekend.

For a filled shed the same logic applies at larger scale: spear on a grid across the heap and at more than one depth, because the surface layer and the core can be different grain in every way that matters.

What buyers test — and what's worth testing at home

Test	Who cares	Worth testing on farm?
Moisture	Everyone	Yes — every load, with a meter you trust
Specific weight	Feed and milling buyers	Yes — cheap kit, quick, flags a poor sample early
Protein	Milling wheat	At intake labs; farm NIR kit exists but is an investment
Hagberg falling number	Milling wheat	Lab test — sample and send if in doubt after a wet spell
Grain nitrogen	Malting barley	Lab test — critical for malting contracts
Screenings / admixture	Malting and most buyers	Rough check on farm with a sieve; lab for contract purposes

Moisture is the non-negotiable one — it decides drying, storage and spec, and a meter checked against your merchant's intake figures makes every load's reading usable. Specific weight is the underrated one: a £100–£300 chondrometer setup gives you the same number the buyer's intake uses, and a low reading at harvest warns you which heap to sell first rather than discovering it in a claim. What the numbers need to hit depends on the contract — the milling wheat specs and malting barley specs guides cover the usual thresholds, and specific weight has its own explainer.

Protein, Hagberg and nitrogen are lab territory for most farms. The practical play is to sample well, split the sample, and send half to a lab before committing a premium crop to a contract that tests for numbers you haven't seen.

Retained samples: the cheap insurance nobody regrets

Here's the scenario that makes the case. A load of wheat leaves in February from a shed filled in August. The buyer's intake reports 16.2% moisture and claims accordingly. Your records say the shed went in at 14.5% average. Who's right? Without a retained sample, it's your recollection against their lab — and their lab is the one holding the money.

With a retained sample, labelled and dry, there's something to re-test. Contracts generally allow for dispute procedures and independent analysis, but only evidence makes them worth invoking.

The habit: keep a sample per load, or at minimum per shed-fill per day, in a sealed bag or tub. Label it properly — date, field, shed, load reference, moisture at intake — because an unlabelled bag of wheat in March is just wheat. Store the samples somewhere cool and dry (a damp sample re-argues the moisture question against you), and keep them until the grain they represent is sold, delivered and paid for.

A season's retained samples cost a few pounds in bags and a shelf in the office. One successful challenge to a moisture or admixture claim on a 29-tonne load pays for a decade of them.

Tie samples to loads, or they're just grain

The thread running through all of this is the link between a sample and a specific load. "We sampled at harvest" is weak; "load 47, Barn Field, 21 August, 14.2% at intake, retained sample on the shelf" is strong. That linkage is a record-keeping habit as much as a sampling one — the same load-by-load discipline that builds honest moisture records builds the sample archive, and if loads are already being logged at a weighbridge, the sample reference is one more field against an entry that already exists.

Frequently Asked Questions

How do you take a representative grain sample?

Draw from several points, not one: spear a trailer at four or five spots at depth, mix the draws in a bucket, and take your test sample from the mix. For a heap in store, sample on a grid across the surface and at more than one depth. A single scoop from one spot is not representative of anything but that spot.

What do grain buyers test for at intake?

Moisture and specific weight on virtually everything; protein and Hagberg falling number for milling wheat; grain nitrogen for malting barley; plus screenings and admixture. Moisture and specific weight are cheap to test at home; the milling and malting quality tests are lab work, and it's worth knowing those numbers before committing a crop to a premium contract.

Should I keep samples of grain I sell?

Yes — a labelled, sealed sample per load (or at least per shed-fill) kept cool and dry until the grain is paid for. Retained samples are what make a dispute over a buyer's moisture or admixture claim winnable months after the load left. They cost pennies; a successful challenge on one artic load can be worth hundreds of pounds.

How often does grain moisture change between loads?

Constantly. Morning loads cut in dew commonly run one to two points wetter than afternoon loads from the same field, and different fields or varieties vary further. That's why per-load sampling beats a daily average — it tells you which loads need the drier and gives every load its own defensible record.