...I would welcome advice on when it's appropriate to use food coloring in a curry and the the timing of when it should be applied.
Hi Chef1707,

These are my comments:
BIRs generally use synthetic food colours (e.g. tartrazine) to produce their vibrant colours (particularly yellows and reds). However, there are some concerns that these synthetic food colours (dyes), which contain E-numbers (e.g. E102 in synthetic yellow), may cause allergies and hyperactivity in some people (e.g. some children) and possibly even cancer (e.g. E123).
Check out this link for more information:
http://nac.allergyforum.com/additives/index.htmlNonetheless, this is what BIRs generally use in dishes such as Pilau Rice, Chicken Tikka Masala, etc.
These synthetic colours arise in so many foodstuffs (e.g. drinks, sweets, pickles, cakes, crisps, ice creams, etc) that, in my (albeit subjective and humble!) opinion, a couple of drops, here and there, in home curry cooking, is very unlikely to kill me any faster! This is my personal opinion, of course, and each of us should make up our own mind on whether to use them or not

These vibrant colours are also purely aesthetic. They add nothing to the flavour of the dish, they simply make the dishes look more attractive and appealing. Any dish will taste equally good (or bad!) without them. So you don't need to use ANY colourings if you don't wish to. Having said that, some natural food colours (e.g. tumeric, saffron, etc) will also add flavour as well as colour.
Synthetic food colours are available in liquid and powder forms. The liquids are not too intense and are suitable for most uses. The powders are far more intense and are useful for making tandoori masalas, etc (where their powder form is maintained). They can also be used in place of the liquid forms (e.g. in rice) by disolving a pinch or two in water.
I usually add the food colours towards the end of cooking. For instance, for rice I add a few drops of yellow and red (and sometimes green) after the rice is cooked. For Tikka Masala, I add a few drops of yellow and/or red (until I have the colour I want) just prior to serving. However, for yellow rice (e.g. Pilau Rice), I add a few drops to the rice whilst its boiling. For tandoori and tikka dishes, I add food colours (liquid or powder; it doesn't really matter) to the marinade. I add powder colours when I make tandoori masala.
Natural food colours are used in traditional (authentic) Indian cooking. These can be used in place of synthetic colours for those concerned about using synthetic colours. However, they are far less vibrant and their colour can deteriorate during cooking. Red is generally achieved using paprika (particularly) and chilli. Deep red (e.g. in Rogan Gosh) is achieved using Ratin Jot (a natural red root). Beetroot powder can also be used. Yellow is generally achieved using tumeric and saffron. Anatto seeds can also be used for an orangey/yellow.
It is probable that your local BIR uses any one of (or a combination of) the above (including a little tandoori masala) to obtain a rich red coloured Patia. They may also include red pepper, tomatoes and/or tomato puree.
Hope this help!
