Quick answer: Real saffron is the red, trumpet-shaped stigma of the Crocus sativus flower, and only a lab test proves its quality. An ISO 3632 report measures color (crocin, 440 nm), flavor (picrocrocin, 257 nm), aroma (safranal, 330 nm) and moisture. Category I, the top grade, needs a coloring strength of 200 or more.
Saffron is considered one of the most expensive spices, as the FDA's saffron method notes, so it gets faked. A good seller answers with numbers, not adjectives. Here is how to read those numbers, with our own lab report as the worked example.
| Measure | What it tells you | Category I | Category II | Category III |
|---|---|---|---|---|
| Coloring strength, crocin (440 nm) | Color | 200 or more | 170 or more | 120 or more |
| Flavor strength, picrocrocin (257 nm) | Bitterness and flavor | 70 or more | 55 or more | 40 or more |
| Aroma strength, safranal (330 nm) | Aroma | 20 to 50 | 20 to 50 | 20 to 50 |
| Moisture and volatile matter, threads | Water weight you pay for | 12% or less | 12% or less | 12% or less |
What does an ISO 3632 lab report measure?
ISO 3632 is the international standard for saffron. Part 1 is the specification, and ISO published its third edition, ISO 3632-1:2025, in July 2025, replacing the 2011 edition. Part 2, ISO 3632-2:2010, sets the test methods.
The core test is simple. The lab dissolves a weighed sample in water and reads how strongly the solution absorbs light at three wavelengths. Crocin, which gives the color, is read at 440 nm. Picrocrocin, the source of saffron's bitterness, is read at 257 nm. Safranal, which carries the aroma, is read at 330 nm. Each result is scaled to a 1% solution in a 1 cm cell and corrected for moisture.
Grading is voluntary, and ISO itself does not test saffron: it says it does not perform certification or issue certificates. A lab tests a sample against the standard and reports the numbers.
What are the ISO 3632 category limits?
Two numbers decide the category: coloring strength and flavor strength. Aroma must fall between 20 and 50 in every category. In the 2011 edition, moisture and volatile matter may not exceed 12% for threads or 10% for powder.
The table above uses the 2011 limits as published in peer-reviewed research. ISO sells the 2025 text, so check which edition a report names.
How is saffron faked?
In the EU's 2021 control plan for herbs and spices, 16 of 141 saffron samples (11%) were suspected of adulteration. Four were mostly safflower and one was marigold. Twelve samples (8.5%) held unauthorized dyes such as tartrazine and sunset yellow, and 11 of those had no foreign plant material at all: real saffron can be dyed.
Researchers have also documented corn silk dyed maroon or neon yellow, saffron stamens and dyed paper strips sold as saffron. Weight gets added with syrup, honey or glycerine, and a 2022 study found silica sand. ISO notes that fraud happens more often with powder, because cheaper spices can be mixed in to add mass.
Can you test saffron at home?
- Look. A real thread is a red stigma that widens into a trumpet at one end, usually with a yellowish-white style at the base, as the FDA's analysts describe it. Dyed corn silk and paper strips are flat, even in width and have no trumpet.
- Soak. Drop a few threads into a clear glass of water. India's food regulator, FSSAI, notes that artificial color dissolves rapidly, while genuine saffron keeps releasing its color for as long as it lasts.
- Snap. FSSAI also notes that genuine saffron does not break as easily as the fake kind.
Know the limits. None of these checks measures crocin, picrocrocin or safranal, and none can rule out dye added to real threads. They can expose a crude fake. Only a lab report shows quality, so buy threads, not powder, from a seller who names the lab and the report number.
What does a real saffron lab report look like?
Here is ours. Report 004389 covers our March 2026 lot, and these are its findings, in the exact words we use:
- Grade A saffron threads from Herat, Afghanistan.
- Tested by the Saffron Quality Control Lab, Herat Directorate of Agriculture, Irrigation and Livestock (Report 004389).
- Meets ISO 3632-1:2010 Category I on all tested parameters.
- No artificial colorants detected.
| Measure | Our March 2026 lot | Limit |
|---|---|---|
| Coloring strength (crocin, 440 nm) | 296.5 | Category I minimum 200 |
| Flavor strength (picrocrocin, 257 nm) | 114.2 | Minimum 70 |
| Aroma strength (safranal, 330 nm) | 32.7 | Range 20 to 50 |
| Moisture | 8.5% | Maximum 10% |
Read it the way you would read any seller's: every value sits inside its limit, and it names the lab and the report number. Our report lists a 10% moisture ceiling; the 2011 edition allows up to 12% for threads, so 8.5% is inside both. When the lot changes, we update these numbers. More on origin and use is on Our Saffron.
Shop the guide
- Raihan Saffron Gift Vial, 1 g, $20: Grade A saffron threads from Herat, Afghanistan, in a gift vial.
- The Saffron Baker's Gift Box, $98, 6 items: 2 g of Raihan Saffron, whole cardamom, a vanilla bean and recipe cards for saffron buns, shortbread and rice.
- The Noël Noir Christmas Gift Box, $148, 8 items, with 1 g of Raihan Saffron and a saffron bun recipe card.
See all Saffron Gifts, or bake with it: our saffron buns recipe uses half a gram for 16 buns.
Questions people ask
What is Category I saffron?
The top ISO 3632 category. In the 2011 limits, it needs coloring strength of 200 or more and flavor strength of 70 or more, with aroma between 20 and 50.
What does 440 nm mean on a saffron report?
It is the wavelength at which the lab reads crocin. The number beside it is the coloring strength; higher means more color.
Is powdered saffron more likely to be fake?
Yes. ISO notes that fraud happens more often with powder, because cheaper spices can be added. Buy whole threads.
Does the water test prove saffron is real?
No. It can expose some fakes, but it cannot measure quality or rule out dye on real threads. Only a lab report can.
Does ISO certify saffron?
No. ISO writes the standard but does not perform certification or issue certificates. Labs test samples against it.
Sources
- ISO: ISO 3632-1:2025, Saffron, Part 1: Specification and ISO 3632-2:2010, Part 2: Test methods
- ISO: Certification and How to recognize quality saffron? (2014)
- Scientific Reports: Locatelli et al., Progress in quality assessment of Italian saffron (2025)
- Foods: Bergomi et al., Determination of Saffron Quality through a Multi-Analytical Approach (2022)
- European Commission, Joint Research Centre: EU coordinated control plan on herbs and spices (2021)
- U.S. Food and Drug Administration: Macroanalytical Procedures Manual, Supplemental Method for Saffron (2024)
- Frontiers in Plant Science: The menace of saffron adulteration (2022)
- Food Safety and Standards Authority of India: DART, Detect Adulteration with Rapid Test
Last updated September 30, 2026 by Emir, founder of Exclusive Gift House.