Every lab report on this site quotes three numbers: crocin, safranal and picrocrocin. They are not marketing inventions. They are the three measurements the international saffron standard, ISO 3632, uses to grade every saffron on earth, and once you know what each one means you can read any saffron report from any lab and know exactly what you are buying. This page explains them without requiring any chemistry.
Three compounds, three senses
Saffron does three things in food: it colours, it perfumes, and it flavours. Conveniently for anyone trying to grade it, each job is done by a different compound, so each can be measured separately.
Crocin: the colour
Crocin is the pigment family that makes saffron worth its price in a biryani or a kheer. It is a carotenoid, a chemical cousin of the pigment in carrots, with one crucial difference: crocin dissolves in water. That is why a few threads can turn a litre of milk gold, and it is why the slow release of colour in a glass of water is a genuine authenticity test. Of the three values, crocin is the one that varies most between good and poor saffron, which makes it the headline number on any report. Higher is stronger.
Safranal: the aroma
Safranal is the volatile oil you smell when you open a pack: honeyed, dry, a little like fresh hay. Here is the interesting part: the living flower contains almost none of it. Safranal forms during drying, as a fragile precursor breaks down in the heat. That is why drying skill matters as much as growing skill, and why badly dried saffron can test high for colour yet smell of very little. Because safranal evaporates, it is also the number that falls first as saffron ages. A fresh, well dried harvest sits comfortably inside the ISO range; a tired one drifts low.
Picrocrocin: the taste
Picrocrocin is the bitter compound that gives saffron its flavour, and it is nearly unique to the saffron crocus, which makes it an excellent fingerprint. Its presence is why a real thread tastes bitter on the tongue and why sweetness is a warning sign. Picrocrocin is also safranal’s parent: it is the precursor that converts into aroma during drying and cooking. A strong picrocrocin number means flavour in the pack and aroma still to come in the pan.
How the numbers are measured
The method is direct. The lab grinds a sample, dissolves it in water, and shines light through the solution at three wavelengths. Each compound absorbs light at its own wavelength: crocin at 440 nanometres, safranal at 330, picrocrocin at 257. The more compound in the sample, the more light it absorbs, and the reading is reported as absorbance for a standard concentration. That is what the notation on our reports means: a crocin of 245 is not a percentage or a mark out of 300, it is how strongly that batch absorbs light at the colour wavelength. What matters for a buyer is simple: within each measurement, higher means more of the compound.
The ISO 3632 categories
ISO 3632 sorts saffron into three categories by these measurements. Category I is the highest. These are the thresholds a filament saffron must meet:
| Measurement | Category I | Category II | Category III |
|---|---|---|---|
| Crocin (colour, at 440 nm) | 200 or higher | 170 or higher | 120 or higher |
| Picrocrocin (taste, at 257 nm) | 70 or higher | 55 or higher | 40 or higher |
| Safranal (aroma, at 330 nm) | 20 to 50 | 20 to 50 | 20 to 50 |
Two details are worth noticing. Safranal is a range rather than a floor, because an implausibly high safranal reading suggests interference rather than quality. And a batch is graded by its worst measurement, not its best: saffron with Category I colour but Category II taste is Category II. We apply the same rule on our own pages, so the category shown against a batch is the honest one.
How to compare two reports
Suppose you are choosing between two packs and both sellers, commendably, show you a report. Read them in this order. First check that each report names an accredited laboratory and carries a test date; an undated report tells you what the saffron once was, not what it is. Second check that the report is tied to a batch code that appears on the pack itself, because a report that could belong to any stock proves very little. Only then compare the numbers, and compare crocin first, since colour strength is where saffron varies most and where you will notice the difference in a dish.
Watch for two quiet tricks. A seller may quote a single flattering number, usually crocin, and omit the other two; a batch with strong colour and almost no aroma is a real and common failure of bad drying, and only the full trio exposes it. And a report may cover powder rather than filaments. ISO 3632 sets separate expectations for powdered saffron, and powder is also where adulteration hides most easily, so a filament purchase deserves a filament report.
A full ISO analysis also measures things buyers rarely ask about: moisture content, since damp saffron weighs more and moulds sooner; floral waste, meaning parts of the flower that are not stigma; and foreign matter. If a lab quotes those too, a low moisture figure and near zero foreign matter are quality signals in their own right. They tell you the drying was competent and the sorting was honest.
What the numbers cannot tell you
Honesty requires the other half of the story. The three values grade strength, not origin: an ISO report will not tell you which valley grew the threads. They are measured per batch, so a report is only meaningful if it is tied to the specific batch in your pack, which is exactly why our packs carry batch codes. And a laboratory number does not replace your own senses; it confirms them. The water test, the smell and the bitter taste described in how to identify real saffron remain worth doing with any saffron you buy, from anyone.
Reading a Karewa report
Every batch we sell is tested at an accredited laboratory before it goes on sale, and the full report is published, not summarised. On any product page you will see the three values for the current batch next to the ISO ranges, and the batch code links to a verification page carrying the report PDF. Try it now: open the lab report index, pick any batch, and read the numbers with what you have just learned. Then, if you like what the evidence says, the current harvest is in the shop.
Frequently asked questions
What is a good crocin value for saffron?
Under ISO 3632, Category I saffron measures 200 or higher for crocin at 440 nanometres. Well handled Kashmiri Mongra frequently measures well above that threshold. Within a category, higher means stronger colouring power.
Why is safranal a range instead of a minimum?
Because more is not automatically better. Safranal is measured indirectly, and a reading far above the expected range usually points to interference or added material rather than exceptional aroma, so the standard treats 20 to 50 as the plausible window for genuine filament saffron.
Do the values fall as saffron ages?
Yes, at different speeds. Safranal evaporates first, then crocin degrades with light and air exposure. This is why a report should carry a test date, why packs should be airtight and dark, and why we print the harvest year on every batch page.
Can a lab report prove saffron is Kashmiri?
Not by the three ISO values alone; they measure strength, not geography. Origin rests on traceability: knowing which batch, from which harvest, from which fields, which is what our batch codes and origin records exist to document.