Counterfeiting saffron is widespread. For many traders, counterfeiting the precious spice is profitable.
Most widespread are fakes of ground saffron. By adding turmeric, the real saffron is stretched or even completely replaced. Paprika powder and even nitrate are also often used by counterfeiters.
If you want to check saffron for authenticity from home, you can resort to a tried and tested chemical detection method: Caustic soda is added to the solution of the "saffron powder". If the powder is pure saffron, the solution turns yellow; if it also contains some turmeric, it turns red.
There are also fakes of saffron threads, but far fewer. They are relatively easy to recognise by their appearance and smell. Real saffron smells sweet but tastes bitter. With fake saffron, the taste is often sweet as well.
Chilli threads, saffron flowers, sandalwood fibres and marigold petals are sold as saffron or mixed in with the real thing.
For the protection of consumers, various quality criteria for saffron are defined internationally and nationally. The international standard ISO/TS 3632-1 regulates the chemical and physical properties.
The ISO standard prescribes a certain value of safranal and crocin. Safranal is an essential oil and crocin is the red dye. Both distinguish genuine saffron.