Most stainless steel pressure cookers have a base made up of aluminium and stainless 'sandwitched' together to stop the hot spots,stainless is also easier to clean,looks better after long term use,and doesn't suffer with acidic deterioration (unless you like aluminium in your food  ) plus the best quality PC are all stainless steel. Aluminium PC have thinner base's making it easier to burn food.

I don't think you can 'make' spiced oil to match the reclaimed oil from the top of a good curry I reckon it would be worth saving some of this oil in a container and smelling it every day to see if there are any changes.
Many things come to mind that points to the oil such as George's post where he had oil from a t/a drip onto the paper carrier what the t/a had come in and this had the BIR smell.
Our favourite t/a up until a few months ago made their curries with plenty of oil with plenty of red nectar on the surface of the curry, recently they have started  using veg ghee in their curries in place of the oil and the flavour has suffered big time 
Our closest t/a use the 'all in one' base and start their curries with a chef's spoon of base,very little oil is visible and very little flavour too 
The BB1 base seems to be good on flavour and that base uses a fair amount of oil.

 The Wife left half of her Chicken Madras (zaal base) which I made on Saturday ( it was a large portion  ) and I just spotted it in the fridge,I then noticed that some of the oil from the curry had dripped onto an egg box which the curry had been perched on WOW  pure BIR  ;D .
The curry itself did smell good but the oil was spot on BIR and far more fragrant than the curry itself.
To me this reinforces what has been found many times on the forum - that BIR flavour is in the oil.
And again the flavour of the curry (with the oil) has improved since Saturday.

Guild Starfire 1V (late 1990's)
Fernandes Telecaster (1980's)
Couple of practice amps and a 100w valve amp, and a Watkins copy cat.
Played rhythm Guitar (Hohner) in a school band in the 60's,love rock n roll,shadows  : and blues.

Quote from: stevejet66 on January 20, 2013, 08:02 PM
Personally i think a lot of you need to go to cookery lessons, BB1's stuff is pukka.

You've spent too long playing with your cucumber sunshine  :

BigBaby1, CA is one of the most respected members on the forum and has probably contributed more than any other member ,he certainly is no ' ass ' when it comes to making curries.
Do you really think he would go to the time and expense plus the excellent photo's just to give your recipe's a not so favorable report ?
I'm getting fed up reading your posts with attitude and this forum was doing OK before you came along !
About time you moved on and take your greasy recipe's with you.

Good work JerryM,interesting thread 

On the subject of oil in BIR's I noticed my local t/a use Pride Rapeseed oil in 20 ltr drums.

Bought one of the Aldi pressure cookers today and all looks good  ' made in China ' 

ps, just noticed the Aldi pressure cooker is exactly the same ( other than the colour of the button on the handle ) as the BEEM ones on Amazon,even the writing on the handles is the same 
http://www.amazon.co.uk/BEEM-F1000-650-X-Press-Pressure-Cooker/dp/B004EHJBJG/ref=sr_1_3?s=kitchen&ie=UTF8&qid=1358113049&sr=1-3

But Beem don't seem to do a 5 litre one.

I got burned quite badly some time ago whilst blending hot base, the stick blender created some sort of vacuum effect and a fair amount of very hot base shot out of the pot and landed on my bare arms  it was bloody hot !!
Blending when cool would be a safer bet if you have time.