Milling wheat specs: protein, Hagberg and specific weight

Full-spec Group 1 milling wheat typically means around 13% protein, a Hagberg Falling Number of 250 seconds or more, specific weight of 76 kg/hl, and moisture at 14.5% — with the usual caveat that your contract is the spec that matters, not the textbook.

Spec	Typical Group 1 requirement	What it measures
Protein	Around 13%	Gluten quantity — the strength of the dough
Hagberg Falling Number	250 seconds or more	Sprouting damage — enzyme activity that wrecks baking
Specific weight	76 kg/hl	Grain fill and density
Moisture	14.5%	Storability and what the mill is actually paying for
Admixture	Low — commonly around 2%	Everything in the sample that isn't sound wheat

Group 2 wheats sit below this — protein requirements are lower or more variable, and the premiums are smaller. The rest of this piece is about what each number actually is, where it's won or lost, and whether chasing the premium stacks up on your farm.

What each number measures

Protein: made in the field, finished with late nitrogen

Protein content is a proxy for gluten, which is what gives a breadmaking dough its structure. It's built almost entirely in the field: nitrogen strategy (particularly late foliar or soil-applied N around flag leaf and after), variety, and season. There's a dilution effect worth knowing — a bumper yield spreads the same nitrogen across more grain, so the barn-filling year is often the year protein comes up short.

Nothing you do in store changes protein. If it's 12.4% at harvest, it's 12.4% at movement.

Hagberg: rain on a ripe crop

Hagberg Falling Number measures enzyme activity from sprouting. When a ripe crop stands through warm rain, grains begin to germinate invisibly, alpha-amylase rises, and Hagberg collapses — sometimes in days. Low-Hagberg flour makes sticky, unsaleable bread, which is why the mills are unsentimental about it.

Hagberg is protected by harvest timing more than anything else: milling wheat earns its place at the front of the cutting queue when the forecast turns. Like protein, it cannot be recovered in store — a sprouted sample stays sprouted.

Specific weight: grain fill

Specific weight is the bulk density of the grain — broadly, how well the grains filled. Drought, disease late in grain fill, and shrivelled samples pull it down. It matters to the mill because thin grain means less flour per tonne. There's more detail in our specific weight guide, and a converter tool if you're working between units.

Moisture

The 14.5% figure is about safe storage and about water: the mill doesn't want to buy it, and grain over spec gets deductions or drying charges. Under-drying costs spec; over-drying gives weight away for free.

The premium maths

Milling premiums over feed wheat have commonly run £20-£60 a tonne, moving around a great deal by season. Take a middling £40/t: on a 40 ha block of Group 1 wheat doing 9 t/ha, that's 360 tonnes and £14,400 of premium. Serious money for the same combine passes.

Now the other side of the ledger. The premium is earned per load that meets spec, and lost per load that doesn't — and the fastest way to lose it on the whole heap is averaging. One field caught by rain, cut at Hagberg 120, blended into a 300-tonne shed of 280-Hagberg wheat doesn't lower the average gracefully; Hagberg blends badly and unpredictably, and the buyer tests what arrives. You can turn a full-spec heap into a feed heap with one afternoon's optimism.

Segregation and retained samples are the insurance

Two disciplines protect the premium:

• Segregate by risk, not just by variety. If one field stood through the rain and the rest didn't, it goes in a different bay until it's tested — even though it's the same variety. Shed space spent on segregation is the cheapest spec insurance there is; our grain storage guide covers the practicalities.
• Sample and retain, load by load. Test protein, Hagberg and specific weight per field or per bay before committing grain to a milling contract, and keep a retained sample from every outgoing load. When the mill's lab disagrees with your expectation, the retained sample is your side of the argument. The sampling and testing guide covers how to sample so the result means something.

Neither habit costs much during harvest. Both are impossible to apply retrospectively.

When a sample fails

Failing spec isn't all-or-nothing, and it's worth knowing the ladder before you're standing on it:

1. Near-misses may still earn something. Some contracts and buyers work sliding scales around protein, and a 12.7% sample against a 13% contract may take a reduced premium rather than nothing. Check your contract's terms before assuming the worst.
2. Group 2 and other flour markets take wheat below Group 1 spec — lower or variable protein requirements, smaller premiums.
3. The floor is feed. A failed milling sample sells as feed wheat at the feed price. That's the whole downside: you carried milling-spec costs (variety, late N, careful storage) and collected the feed price.

The floor being feed is also the comfort: a failed sample is a lost premium, not a lost crop.

Frequently Asked Questions

What protein does milling wheat need?

Full-spec Group 1 breadmaking wheat typically requires around 13% protein, though contracts vary and some work sliding scales around that figure. Group 2 wheats have lower or more variable requirements. Check your contract — the premium is paid against its numbers, not the textbook's.

What is a good Hagberg Falling Number?

Milling contracts typically ask for 250 seconds or more. Sound, unsprouted wheat harvested in decent conditions usually sits comfortably above that; the number collapses when a ripe crop stands through warm rain and grains begin to sprout.

Can you fix protein or Hagberg in store?

No. Protein is set in the field by nitrogen, variety and season; Hagberg is destroyed by sprouting before or at harvest. Storage can only preserve what came off the combine — which is why testing before blending matters so much.

What happens if milling wheat fails the spec?

Depending on how far out it is: a near-miss may earn a reduced premium under a sliding scale, wheat below Group 1 spec may find Group 2 or other flour markets, and the floor is selling as feed wheat at the feed price. The loss is the premium and the extra growing costs, not the crop itself.