Specifying West African sesame before contract: purity, oil content and the clauses buyers should fix

Specifying West African sesame before contract: purity, oil content and the clauses buyers should fix

Purity, admixture, oil content and the moisture ceiling belong in the contract as numbers with defined tolerances, an agreed method of analysis and a stated allowance or rejection clause. Leave them to pre-shipment sampling and the risk lands on the buyer after the price is fixed.

IndexBox reports that Nigeria remains Africa's largest sesame seed producer and that variable oil content, foreign matter contamination and inconsistent moisture are what cause shipment rejections and price discounts in premium markets.

What has to be on a West African sesame specification sheet?

The sheet should name five measurable attributes: purity, admixture, oil content, moisture and free fatty acid (FFA). A study of sesame seed quality published in Heliyon sets out the parameters it describes as standard for international trade: a minimum 98% cleanliness, a minimum 51% oil content, a maximum 6% moisture and a maximum of 1% foreign matter or 2% off-colour seeds.

Those are baseline figures. Nigerian offers typically quote purity from 98% upward, oil content in the high forties to low fifties and moisture ceilings of 6% to 8%. Nothing on an offer sheet binds until it is in the contract.

Attribute	Trade baseline	Who prioritises it	Contract mechanism
Purity	98% minimum	confectionery, retail	basis with allowance
Admixture	1% foreign matter, 2% off-colour	all buyers	rejection plus sliding allowance
Oil content	51% minimum	oil crushers	basis with shortfall discount
Moisture	6% maximum	long-transit buyers	ceiling, no allowance
FFA	named attribute; cap set per contract	crushers, premium	ceiling or repricing

Why does the moisture ceiling deserve its own clause?

Moisture moves the other numbers. Gombella notes that elevated moisture accelerates FFA development and creates the conditions for discoloration and mould, that moisture above 7% is where deterioration starts, and that most contracts call for moisture between 5% and 7%.

Tridge, summarising Ghana's export guidance, puts the moisture target at 8% or below and purity at 98% or higher for premium grades. A buyer fixing 6% and a seller offering 8% are not describing the same lot.

Moisture is also a food-safety term. The EU caps aflatoxin B1 at 2 µg/kg and total aflatoxins at 4 µg/kg in sesame seeds, per a 2026 study in Springer's Mycotoxin Research.

Which numbers belong in the contract as tolerances?

All five, but the contract adds what the offer sheet omits: the tolerance. A specification says purity 98% minimum. A contract says what happens at 97.5%.

The FOSFA 26A oilseed contract shows the mechanic. On admixture, the buyer may reject a parcel over 4%; below that, the buyer is entitled to an allowance of 2% of the price for each 1% of admixture above the basis up to 3%, rising to 4% for each 1% between 3% and 4%. Basis and excess are both defined.

Three clauses make the numbers enforceable, following the same evidence discipline as counting defects in a graded lot: the method of analysis, the sampling point and the analyst. Moisture measured to ISO 665 and oil content to ISO 659 give both sides the same reading, and fixing whether the pre-shipment certificate is final removes the second lab report that arrives after loading.

Fluna connects buyers with verified Nigerian and Ghanaian exporters, attaches quality documentation to each lot and manages freight on the East Africa freight lead times lane. Contact our commodity desk to specify sesame on fixed contract terms.

FAQ

Q: What oil content should a buyer require in Nigerian or Ghanaian sesame?
A: The Heliyon study of sesame quality in northern Ghana gives 51% oil content as the international trade minimum. Nigerian offers commonly quote the high forties to low fifties, so fix the contract figure against a stated method.

Q: Is 8% moisture acceptable for export sesame?
A: Ghana trade guidance summarised by Tridge targets 8% or below, but most contracts call for 5% to 7%, and moisture above 7% is where mould and FFA problems begin.

Q: What happens if admixture exceeds the contract basis?
A: Under the FOSFA 26A model, the buyer may reject a parcel over 4% admixture, and between the basis and 4% receives a price allowance of 2% per 1% up to 3%, and 4% per 1% between 3% and 4%.