How to Read a Saffron Lab Report
"ISO 3632 Category I" on a label tells you the seller passed. It does not tell you by how much. The number does.
"ISO 3632 Category I" on a label tells you the seller passed. It does not tell you by how much.
The number does. Here is how to read one.
The three numbers
ISO 3632-1:2011 measures three things by ultraviolet and visible light spectrophotometry, each at its own wavelength, all reported on the E1% scale.
- Crocin, read at 440nm. This governs colouring strength.
- Picrocrocin, read at 257nm. This governs taste.
- Safranal, read at 330nm. This governs aroma.
Three numbers, three wavelengths, three different things. A report that gives you one number is not a full report.
What the E1% scale means
You will see the values written as bare numbers, and they are not percentages of anything obvious.
E1% is a standard way of expressing how strongly a solution absorbs light at a given wavelength, normalised so that different laboratories testing the same material get comparable figures. What matters for a buyer is that it makes reports comparable. A crocin figure from one lab can be read against a crocin figure from another, because both are on the same scale at the same wavelength.
That comparability is the entire reason to ask for numbers rather than adjectives.
What Category I requires
For Category I, the thresholds are roughly these: crocin at a minimum around 190 for filaments, picrocrocin above 70, safranal between 20 and 50, and moisture at 12 percent maximum.
Now the honest part. Sources quote the Category I crocin floor as both 190 and 200. They are not all wrong. The thresholds differ between filament and powder, and different published summaries pick different rows from the same standard.
We are not going to resolve that for you by picking the number that flatters us. If you see 190 in one place and 200 in another, that is why. What matters more is the actual figure on your report and how far above the floor it sits.
Passing is not a score
This is the point of the whole article.
Category I is a band, not a value. A batch that scrapes in just above the floor and a batch well clear of it both print "Category I" on a label. They are not the same product, they will not behave the same in a pan, and one of them justifies a higher price.
The same applies to safranal, which has a range rather than a floor: between 20 and 50 for Category I. A figure sitting near the bottom of that range is a passing figure and a faint-smelling saffron.
So when a label says Category I, the correct next question is always: what were the numbers?
Why a red batch can still test weak
Colour is the thing people judge by eye, and it is the easiest thing to be wrong about.
Crocin at 440nm is a measurement of colouring strength in solution. A batch can look deeply red in the tin and still return a modest crocin value, because what your eye reads as red is surface appearance rather than extractable colour. It can also be red because something was added to make it red, which is a different problem covered by a different test.
This is the whole reason the standard exists. Your eye is not a spectrophotometer.
Moisture, and how weight gets padded
Moisture maximum is 12 percent, and it is the quiet one.
Saffron is sold by weight. Water weighs something. A batch carrying more moisture than it should gives you fewer threads per gram, and every one of those threads is a little weaker than it looks. Nothing has been added that would show up as an adulterant. You have simply paid saffron prices for water.
Moisture is also the figure most often missing from a summary that a seller quotes at you. Check it is on the report. If it is not, ask why.
What spectrophotometry cannot see
The three values are chemistry. They do not tell you what the material physically is.
Two other methods cover that.
- Microscopy looks at structure. A genuine saffron stigma has a trumpet shape at one end. Safflower, marigold petal and dyed corn silk do not.
- HPLC looks for artificial dyes such as Tartrazine, Sudan dyes and Amaranth, which exist to make weak or fake material look strong.
A full picture needs all three approaches. Spectrophotometry for potency, microscopy for structure, HPLC for what should not be there at all. A report covering only the first leaves the other two questions open.
What a report should have on it
Beyond the numbers themselves, a report worth anything carries:
- The name of the laboratory and its accreditation.
- The date of the test.
- A lot or batch identifier that matches the tin in your hand.
- The method used for each value.
The lot number is the one people forget. Without it, a report is a document about some saffron, somewhere, at some point. With it, the report is about your tin.
Our report
Our saffron is independently tested to ISO 3632 by the India International Kashmir Saffron Trading Centre in Pampore, NABL TC-9209, and we send the report on request. You can see the tins it applies to on our products page.
The short version
A label that says Category I is a pass mark with the score rubbed off. Ask for the score. Ask which lab. Ask for the lot number.
Any seller who tests their saffron has these documents sitting in a drawer. The only reason not to show you is not having them.