Every few months a state food-safety raid makes the news, a lab report names a brand, and the same question comes up at our counter: how do I know what is actually in this packet? You cannot run a chromatograph in your kitchen. But you can run four or five simple checks that the Food Safety and Standards Authority of India publishes itself, and they will catch the crude adulteration that is most common in ground spice.
This guide covers the three powders people ask us about most — chilli, turmeric and coriander. Each test below comes from FSSAI's DART handbook (Detect Adulteration with Rapid Tests), the set of kitchen-level checks the regulator wrote for ordinary households. We have added what we see from the milling side of the counter, because knowing why a spice gets adulterated tells you a lot about where to buy it.
First, what "adulterated" actually means
It is worth separating two very different problems, because they need different tests.
Bulking agents are cheap solids added to increase weight — brick powder or sand in chilli, chalk or starch in turmeric, dung powder or husk in coriander. They are crude, they are heavy, and they usually sink. These are the easiest to find at home.
Colouring agents are the more serious problem. Industrial dyes such as Sudan Red, Rhodamine B and metanil yellow are added because consumers buy on redness and yellowness. They are not food colours. Several are classified as carcinogenic, and unlike grit they cannot be seen, felt or rinsed away. Most of the tests below are aimed at these.
There is a third category worth naming honestly: dilution with spent material — spice from which the oil has already been extracted, milled back into the powder. It is not toxic. It simply means you are paying spice prices for something with the flavour taken out. No home test finds it reliably. Smell does, a little: spent spice is flat.
Chilli powder
Test 1 — the water glass test for added colour
Fill a clear glass with water. Sprinkle half a teaspoon of chilli powder on the surface and do not stir. Watch for a minute.
Pure chilli powder floats for a while and then sinks more or less as a mass, and the water below stays reasonably clear at first. If a water-soluble dye has been added, you will see coloured streaks running down through the water from the floating powder — thin red trails, quite distinct from the powder itself descending. That streaking is the signal.
Test 2 — the paraffin rub for Rhodamine B
Rhodamine B is the dye most often found in chilli powder. Take a cotton ball, dip it in liquid paraffin (or coconut oil at a pinch), and rub it against a small heap of the powder. If the cotton picks up a bright pink or magenta stain, that points to Rhodamine B. Natural chilli will tint the cotton a dull orange-red, not a fluorescent pink.
Test 3 — the grit test for brick powder and sand
Stir a teaspoon of powder into a glass of water and let it stand for a few minutes. Brick powder, sand and soapstone are heavier than chilli and settle as a distinct gritty layer at the bottom. Pour off the water and rub the sediment between your fingers: chilli sediment is soft, brick and sand are abrasive.
Turmeric powder
Test 4 — the acid test for metanil yellow
This is the important one. Metanil yellow is a textile dye used to make pale turmeric look vivid, and it is banned in food.
Put a teaspoon of turmeric powder in a glass and add a few drops of concentrated hydrochloric acid diluted in a little water. Pure turmeric turns pink or violet — and that colour disappears when you add more water. If the pink or violet persists after dilution, metanil yellow is present.
If you would rather not keep acid in the kitchen, the water test still helps: pure turmeric settles leaving a faint lemon-yellow tint, while heavily dyed turmeric releases a strong, bright yellow immediately.
Test 5 — iodine for starch and chalk
Mix a little turmeric in water and add two drops of tincture of iodine. A blue-black colour means starch — rice flour or arrowroot bulking the powder out. A separate clue for chalk: add a few drops of dilute hydrochloric acid and watch for effervescence, the fizz of chalk reacting.
Coriander powder
Test 6 — the float test for husk and dung powder
Coriander is bulked with its own spent husk, with sawdust, and — the reason this test exists — with dried dung powder. Sprinkle the powder on water. Dung powder and husk float and can be skimmed off the surface; genuine coriander wets and sinks. A strong, sour or barnyard smell in the wet powder is a second sign.
Test 7 — iodine again, for starch
The same iodine test applies: blue-black means starch has been added. Coriander is one of the easiest powders to dilute because its flavour is mild enough that a 20% cut is hard to taste.
What these tests can and cannot tell you
We want to be straight about this, because a lot of content on this subject over-promises.
These tests are indicative, not conclusive. They find crude, high-dose adulteration. They will not detect low-level dye, pesticide residue, aflatoxin from bad storage, or heavy metals — and those are the contaminants that matter most for long-term health. A negative kitchen test is reassuring; it is not a clean bill of health.
The only thing that settles those questions is a laboratory. We publish our own third-party test reports — including colour value, added-dye screening, pesticide residue and aflatoxin — on our lab reports page, batch by batch. If a brand will not show you that, the kitchen tests above are all you have.
The simpler answer: buy it whole, or watch it milled
Every adulterant described above has one thing in common: it needs the spice to be already ground before it reaches you. You cannot hide brick powder in a whole chilli or metanil yellow in a whole turmeric finger. Grinding is the step where things get added, and it is the step most customers never see.
That is the whole reason our shops mill in front of the counter. You pick the whole spice, you watch it go into the mill, and you take the powder home the same day. There is no window in which anything can be added, and no months of shelf life during which the volatile oils quietly evaporate.
If you are in Hyderabad, our Kondapur and Serilingampally stores mill to order six days a week — you are welcome to come and watch the machine run before you buy anything.
What we sell, and what is in it
- Premium Kashmiri Chilli Powder — milled from whole Kashmiri pods, no added colour, no anti-caking agent.
- Lakadong Turmeric Powder — single-origin Meghalaya turmeric, tested for curcumin content and for lead chromate.
- Brown Coriander Powder — whole seed ground to order, no husk filler.
Run the tests above on ours. That is genuinely the point of publishing them.
Sources: FSSAI, DART — Detect Adulteration with Rapid Tests, Food Safety and Standards Authority of India. The tests described are the regulator's own household methods and are indicative only; laboratory analysis is required for a definitive result.