Well done Haldi! I can't wait to try this. If at all possible, a picture of your used oil would be very helpful. Did you target a take away that didn't make fish, or do they all use a separate fryer for fish and you asked for the chip fryer oil? What kind of take away do you suggest that we approach?
I must say, I always thought the missing taste would be something filth related ;D. I can really imagine it's used oil doing the trick. Although all the small food particles in the oil have been fried and fried, tyey will have been sealed on the outside by the hot oil. Boiling the oil up in the base sauce will release all of that sealed in fried tastiness. This could explain why the oil doesn't smell of much until used in base sauce.
I'm really excited about this breakthrough. Once Haldi manages to post his advice on acquiring the right kind of used oil then I'll go and try to get some. The chip shop near me serves fish so I think perhaps I should try elsewhere.
Once I have the oil, I'm tempted to try a very minimal curry session. A basic minimally spiced base with just onion, tomato, garlic, ginger, turmeric, cumin, coriander powder and paprika (all spices used sparingly, E.G. 2 dsrt spoons total) and a BE style curry with just 1 tsp spice mix. Really looking forward to it!
Congratulations on your obsessive hard work finally paying off Haldi! ;D Well deserved! If anyone was going to get there it was going to be you!
As far as your health concerns go, I wouldn't worry too much. As long as your only getting a few tbsps a couple of times a week it'll be fine. I imagine saturated fat would be worse for you. Just try not get the oil smoking when you cook with it because as I'm sure you know, that makes it more carcinogenic. That's the only concern really. Any microbes in there would be dead instantly at that temp! The stuff's probably sterile!
Does the darker oil effect the colour of your base and/or curry?
Cheers,
BB.