The colour value of chilli powder is checked in a laboratory by measuring extractable colour, most often reported in ASTA colour units. The lab extracts the colour pigments with a solvent and reads the result on a spectrophotometer.
Do not judge colour by eye alone. A bright powder can owe its colour to added dye or oil, and a dull one can still test well. Put a minimum ASTA value and the test method in your contract, and test each lot.
What colour value tells you
Red chilli gets its colour from natural carotenoid pigments. The ASTA value is a measure of how much of that colour the powder contains. Higher values mean a deeper red that goes further in a recipe.
Colour value depends mainly on the chilli variety, the crop year and how the pods were dried and stored. Some Indian varieties are traded for colour and others for heat. Our guide to why ASTA colour value matters covers the varieties and the trade-off between colour and pungency.
How to specify and test it
- State a minimum ASTA value that suits your use, agreed after testing samples. Any figure is product and grade specific.
- Name the method, for example the ASTA method for extractable colour, so both labs measure the same thing.
- Ask for colour value on the certificate of analysis for each lot, not a typical value for the product.
- Have the pre-shipment sample tested by an independent lab before loading.
- Keep a retained sample from each lot in case of a dispute.
Colour falls over time
Chilli colour is not stable. Carotenoids break down with light, heat and oxygen, so a powder that tests well at the factory can test lower months later. Powder loses colour faster than whole pods because more surface is exposed.
Agree whether the minimum applies at dispatch or on arrival, and ask for packing that blocks light and limits oxygen. Store the powder cool and dark once it lands.
Watch for artificial colour
Because colour drives value, chilli powder has a history of adulteration with illegal dyes such as Sudan dyes. These boost apparent colour and are banned in food in the EU, UK and US. A high ASTA reading does not prove the colour is natural.
If your market is strict, include a test for Sudan dyes and other prohibited colours alongside colour value. See whether Sudan dye is still a risk in Indian chilli for the background.
How we help
We source chilli powder from grinders who buy the right varieties for colour, and have each lot tested for ASTA colour and prohibited dyes at a NABL-accredited lab. We share the original reports with you. To set up a chilli powder spec, ask for a free sourcing review.