How flour mills calculate wheat moisture and QC deductions

Every wheat lot that reaches a flour mill gets checked before it is weighed into stock. Moisture is measured, HL is taken, and the lab looks for refraction (damaged and shrivelled grain) and mitti (dust and dirt). When a reading is worse than the mill's standard, the mill deducts a claim from the weight or the amount it pays.

This is where most gate disputes start. The vendor sees the readings, the munim works out a figure, and the two sides argue about how it was reached. This guide explains how the common deduction methods work, with worked examples, so the rule is clear to everyone before the next truck arrives.

The four parameters most mills check

Parameter	What it tells you	A claim applies when the reading is
Moisture	Water in the grain. Wet wheat weighs more and stores badly	Above the standard
HL (hectolitre weight)	How dense and well-filled the grain is	Below the standard
Refraction	Broken, shrivelled and damaged grain	Above the standard
Mitti	Dust, dirt and other foreign matter	Above the standard

Each mill sets its own standard for each parameter. For moisture, 12% is the common reference point. The direction matters: a high moisture reading is bad, but a high HL reading is good, so HL is claimed only when it falls below the standard.

Work on the average, not one reading

Labs usually take more than one reading from a lot. The fair way to decide a claim is to compare the average of the readings with the standard.

Say three moisture readings on one lot are 13.0, 13.4 and 14.1. The average is (13.0 + 13.4 + 14.1) ÷ 3 = 13.5. Against a 12% standard, the lot is 1.5 points over.

Now take a lot with readings of 11.6, 11.9 and 12.4. One reading is above 12, but the average is 35.9 ÷ 3 = 11.97, which is below the standard. No moisture claim applies. Deciding on the average stops a single high reading from turning into an argument.

Four ways to calculate the claim

The examples below use the same lot: 100 quintals gross weight in 200 bags, bought at ₹2,500 per quintal.

1. Percentage of weight

The claim is the difference from the standard, multiplied by a ratio, taken as a percentage of the gross weight.

Claim % = (average − standard) × ratio Claim in quintals = gross × claim % ÷ 100

With the moisture average of 13.5, a 12% standard and a ratio of 1:

• Claim % = (13.5 − 12) × 1 = 1.5%
• Claim = 100 × 1.5 ÷ 100 = 1.5 quintals, worth 1.5 × 2,500 = ₹3,750

Some mills use a lower ratio, for example 0.5, which halves the claim to 0.75 quintals. For HL the difference is taken the other way round: with a standard of 76 and an average of 74.5, the difference is 76 − 74.5 = 1.5.

2. Flat amount per quintal

The mill deducts a fixed rupee amount for every quintal once the parameter crosses the standard.

At ₹10 per quintal on a 100-quintal lot, the claim is 100 × 10 = ₹1,000. At ₹2,500 per quintal that is equal to 1,000 ÷ 2,500 = 0.4 quintals.

3. Flat amount per bag

The same idea, charged per bag instead of per quintal.

At ₹5 per bag on 200 bags, the claim is 200 × 5 = ₹1,000, again equal to 0.4 quintals at ₹2,500.

4. Slabs

Many mills prefer a table: readings in each range carry a fixed deduction percentage. For mitti, a slab table might look like this:

Mitti reading	Deduction
0 to under 1%	0%
1 to under 2%	0.5%
2 to under 3%	1%
3% and above	2%

With a mitti average of 2.4, the lot falls in the 2 to under 3% slab, so the deduction is 1%: 100 × 1 ÷ 100 = 1 quintal, worth ₹2,500. A reading of exactly 2.0 belongs to the 2 to under 3% slab, not the one below it.

In slab mode the standard is not used; the zero-deduction slab does the same job. Leaving the last slab open-ended ("3% and above") means every reading has a slab. If the last slab is closed, decide in advance what happens to a lot that reads above it.

Try it on your own lot: the wheat QC claim calculator works out each claim, the bag deduction and the net amount as you type, using any of these four methods.

Claims add up, and so does the bag weight

A lot can carry claims on more than one parameter. Each parameter is worked out on its own rule and the claims are added.

Mills also deduct the weight of the empty jute bags from the gross weight. With 200 bags at 0.5 kg each, that is 200 × 0.5 ÷ 100 = 1 quintal. So for our lot with a 1.5-quintal moisture claim and a 1-quintal mitti claim:

Net weight = 100 − 1.5 − 1 − 1 = 96.5 quintals Amount = 96.5 × 2,500 = ₹2,41,250

Settled claims

Sometimes the mill and a regular vendor agree on a different figure. The rule might give 1.5 quintals, and after discussion both sides settle at 1 quintal.

The settled figure should replace the calculated claim on that lot, and the reason should be recorded. Without a record, the next dispute with the same vendor starts from nothing. Some mills also mark specific lots as no-claim, for example for a trial supply.

Where the 12% figure comes from

The 12% moisture reference is widely used because government procurement uses it. Reporting on wheat procurement describes 12% moisture as the permissible limit (The Tribune), with farmers taking a price cut above 12% and wheat above 14% moisture rejected by FCI (Down To Earth). Private mills set their own commercial terms, but many use the same numbers as a starting point.

Put the rule in writing, then in your software

Most claim disputes come from the rule living in one person's head. Write down, for each parameter:

1. The standard.
2. The direction that triggers a claim.
3. The method: percentage with a ratio, flat per quintal, flat per bag, or slabs.
4. Who can approve a settled claim.

Then apply it the same way on every lot. GrainTech does this at raw material entry: you set the standard, direction and method for each parameter once, enter the readings at the gate, and the claim is calculated on the average and shown in quintals and rupees. See how wheat procurement and QC claims work in GrainTech, or check a lot now with the QC claim calculator.