ISO 3632, explained properly.
Every serious saffron offer quotes it. Very few explain it. This is what the standard actually measures, what the categories mean, and which numbers you should refuse to buy without.
Colour, taste, aroma — each one measurable.
ISO 3632-2 dissolves a sample and reads its absorbance in a spectrophotometer at three wavelengths. Each reading is reported as E¹% 1cm — the absorbance of a 1% solution in a 1 cm cell.
The carotenoid that makes saffron yellow a dish. This is the headline figure and the one that most closely tracks price. Higher crocin means fewer grams for the same result.
The glycoside behind saffron's characteristic bitterness. It degrades with age and poor storage, so a low figure on a young lot is a warning sign.
The volatile that gives saffron its hay-like smell. Unusually, the standard sets a band rather than a floor: too high suggests over-drying.
What Category I actually guarantees.
| Threshold | Category I | Category II | Category III |
|---|---|---|---|
| Crocin (min, 440 nm) | ≥ 190 | ≥ 150 | ≥ 100 |
| Picrocrocin (min, 257 nm) | ≥ 70 | ≥ 55 | ≥ 40 |
| Safranal (band, 330 nm) | 20–50 | 20–50 | 20–50 |
| Moisture & volatile matter | ≤ 12% | ≤ 12% | ≤ 12% |
| Typical grades | Mongra · Super Negin · Negin · Sargol | Lacha · Pushal | Lower commercial grades |
These are the published thresholds of the standard, not Pravaha's own claims. Pravaha ships against Category I and Category II and states the measured value for your lot on its certificate of analysis.
Why "Category I" alone is not enough
Category I is a floor, not a score. A lot measuring crocin 191 and a lot measuring crocin 245 both qualify as Category I — but the second delivers roughly a quarter more colour per gram. If a supplier will only tell you the category and not the measured figure, you are being sold the floor.
Always ask for the number. A supplier who tests their lots has it on hand; a supplier who does not will change the subject.
What the standard does not cover
ISO 3632 is a specification for saffron quality. It does not certify origin, it does not detect every form of adulteration on its own, and it says nothing about pesticide residue or heavy metals. For those you need separate testing — which we will arrange on request.
It is also worth knowing that the 2011 revision folded the old Category IV into Category III and tightened the test methods. An old certificate quoting four categories is quoting a withdrawn edition.
How to read an offer sheet
Four lines tell you almost everything. Form — whole thread, or broken tips sold as thread? Category — with the measured figure beside it, not on its own. Moisture — high moisture is water you are paying saffron prices for. Date of analysis — a certificate from three harvests ago describes a different lot.
If all four are present and the numbers are specific, you are dealing with someone who tests. If they are vague or missing, the price is not the risk — the product is.
ISO 3632 in practice.
No. It is a voluntary international standard, not a legal requirement in most importing countries. That is exactly why it separates serious suppliers from the rest — nobody is forcing anyone to test.
Once per lot, before release. Because saffron degrades with time and light exposure, a certificate is a statement about a specific lot at a specific date — not a permanent property of the supplier.
Added dyes will lift an absorbance reading, which is why the full ISO 3632-2 method includes checks designed to expose them, and why reputable laboratories run additional screening. Buy against a report from an accredited lab rather than a figure typed on a letterhead.
The standard permits up to 12%. We ship at 10% or below. Above 12% you are buying water at saffron prices and inviting mould in a long container transit.
Sample first. Decide after.
Tell us the grade and volume you are working to and we will send an indicative offer, the specification sheet, and a sample dispatch window — normally within one working day.