Ask for the curcumin level your product needs, measured on the lot by a method you name in the contract. For ordinary culinary turmeric, curcumin is usually in the low single digits as a percentage, and it varies with origin, season and processing.
A higher figure costs more. Only pay for it if colour or health positioning matters to your customer.
What curcumin is
Curcumin is the main yellow pigment in turmeric. Labs often report curcuminoids, which include curcumin and two related compounds. It gives turmeric its colour and is the compound most health claims refer to.
Curcumin levels differ by origin, by the age of the crop and by how the rhizomes were cured and dried. Poor drying and long storage in light can both lower the figure. That is why a figure quoted for a variety tells you less than a test on the lot.
Whole turmeric is not the same as turmeric extract. Extracts for supplements are concentrated to very high curcuminoid levels. Do not compare a spice lot with an extract figure.
The method changes the number
This is the most common source of disputes. Different methods give different results on the same sample.
- Spectrophotometric methods, such as the ASTA method, measure total colour and usually read higher.
- HPLC separates and measures each curcuminoid and usually reads lower and more precisely.
- Results can be reported on an as-is basis or on a dry basis, which also changes the figure.
Setting your figure
Start from your use, then test samples from two or three origins with the same lab and method. Set your minimum just below what an approved sample gave, so normal variation does not cause a rejection.
- Culinary powder and blends: a standard lot is often fine. Focus on colour, cleanliness and contaminants.
- Colour-led uses such as mustards, sauces and snacks: ask for a higher curcumin lot and test it.
- Health and wellness retail: higher-curcumin origins, with the method and basis stated on the label claim you plan to make.
- Extraction: buy on a tested curcuminoid figure and price against it.
Watch for shortcuts
A high curcumin claim on a cheap lot is a warning sign. Colour can be faked with added dyes, and in some cases with lead chromate, which makes turmeric look brighter. A high colour reading is not proof of high curcumin.
Ask for an HPLC result on the actual lot, and test for lead and chromium alongside it. Our guide to checking turmeric for lead chromate explains why. For origins known for higher curcumin, see the main turmeric finger varieties.
Finally, agree in the contract which lab settles a dispute, and keep a sealed retained sample from every lot. Two honest labs using different methods can report quite different curcumin figures on the same turmeric.
How we help
We have samples from competing lots tested side by side at an NABL-accredited lab using the method you name, so you compare like with like before booking. To set a curcumin figure that suits your product, start with a free sourcing review.