Sesame seeds from Tanzania: purity grades explained

98%, 99%, 99.5% sortex, crushing grade — what the purity figure actually measures, who buys which grade, and why asking for the highest one is not always the right move.

Almost every sesame enquiry we receive uses the phrase "natural white sesame", and almost every one of them means something slightly different by it. The word that resolves the ambiguity is purity, and it is also the word that moves the price more than any other on this commodity.

Purity is the proportion of clean, sound seed left after cleaning — in other words, how little of anything else is in the bag. We supply natural whitish sesame at 98% purity, at 99% purity and at 99.5% purity, the last of these being sortex quality, alongside a mixed and crushing grade. For the 99.5% grade the admixture tolerance is 0.5% maximum, and for sorted grades foreign matter is 0.5% maximum.

Who buys which grade follows from what the seed is for. Hulling and confectionery buyers work at the higher purities, because a seed that will end up whole and visible on a product has to look uniform; colour sorting is available on request for exactly that reason. Crushers buy the mixed and crushing grade, because oil content and free fatty acid decide their yield and appearance does not. Paying a sortex premium for seed that is going into a press is money spent on a property the buyer will never use.

Purity is not the only number in the specification, and for a crusher it is not even the most important one. Our indicative figures are oil content of 48 to 52% on a dry basis, free fatty acid at 2% maximum, moisture at 7% maximum, and damaged and discoloured seeds at 1% maximum. As with every specification on this site, those are typical trade ranges for Tanzanian origin subject to confirmation by our quality and operations department, and the binding version is the one in the sales contract.

The grade is reached, not found. Seed is machine cleaned and gravity separated to the purity specified, and colour sorted where the buyer's use requires it. Each of those steps costs something and each removes saleable weight along with the impurities, which is the honest reason a higher purity carries a higher price. Ask for the purity your process needs rather than the highest one on the list, and say what the seed is for — that single sentence usually settles the grade faster than a specification sheet does.

On season and shipping: sesame is sourced from the southern and central growing belts and the harvest runs broadly from June to September, so the widest choice of grades is available in and shortly after that window. It ships in 25 kg and 50 kg woven polypropylene bags, in bulk bags, or loose in the container where the specification allows, with an indicative minimum of one 20 ft container load. We quote EXW, FCA, FOB, CFR and CIF.

Send us the purity you need, what the seed is for, the quantity and the discharge port, and we will confirm against the current crop position before quoting.