Turmeric stains – a fact that is made clear to me every time I make curry and a drop ends up on my light coloured counter tops (what were the previous owners thinking when they installed baby blue counter tops?). Turmeric seems to stain more than any other spice I use, why?
First, a bit about turmeric. Native to South Asia, turmeric plants thrive in the moist, hot conditions found there. It's a member of a tasty family including: ginger, galangal and cardamom. The name 'turmeric' may originate from the Latin terra merita, which means merit of the earth. The turmeric powder commonly used as a spice is derived from the rhizome, a horizontal stem that typically grows shallow beneath the soil. From this stem, roots and shoots are sent out. These rhizomes are harvested about nine months after planting, then boiled, peeled and dried in the sun. Once dry, it is ground into a power.
About turmeric, Marco Polo said “There is also a vegetable which has all the properties of true saffron, as well as the smell and the colour, and yet it is not really saffron.” In medieval Europe, this spice was called 'Indian saffron' and was commonly used as an alternative to the expensive saffron. According to 'The Flavor Bible' turmeric has a bittersweet pungent flavour. Today it's commonly used to make mustard yellow, and as a component in curries that adds both flavour and colour. At times, turmeric even been used to colour cheeses, margarine and chicken broth. I wouldn't mind at all if turmeric was used as a colourant in my iron pills because it can do some good. In fact, a long list of potential medicinal uses have been attributed to turmeric, one use that has been proven is that it reduces inflammation.
Turmeric's use as a dye probably dates back as long as it's been used. I can't imagine not to noticing that turmeric stains cooking implements once it's added to a dish, however, the first record of using turmeric as a dye comes from an ancient Assyrian herbal recipe dating back to 600 BC (a fact from The Cook's Encyclopedia of Spices). The yellow colour is caused by curcumin, a chemical component of turmeric. About 5% of the dry powder is curcumin. The colouring components of other spices like paprika are less than 1%, so, to answer why turmeric stains more, there is just more colouring potential in the turmeric. On the plus side, turmeric fades in sunlight – so if a drop of curry ends up on a favorite white shirt put it in the sun for the colour to fade.