Guys-have a look here, i have tried these and you can get high temps in a domestic oven.
You can get them in the UK but sadly I lost mine when my (now ex)wife cleared the house out while I was at work!
http://www.romertopfonline.com/clay-bakers/
Hope this helps
Phil

Hello Axe
I had the same problem-until I found this site

http://www.uni-graz.at/~katzer/engl/index.html

Very useful as it gives translationsin to lots of languages.
Hope this Is whatyou were looking for.

Phil

Axe- I hear what you say,I'm just thinking that in a BIR environment, the sauce is always on the stove,and therefore always cooking-the base sauce recipes one here are probably very authentic to a point, but they seem to be cooked fairly quickly,from what I've read then they get portioned up and chucked in the freezer, whereas the BIR version, would be stewing a lot longer and therefore releasing its sugars slowly.
Having said that-what do I know!, I'm a relative newbie and I've never worked In a BIR,and whilst I think the base sauces on here are authentic, I'm guessing that they get cooked a lot longer in a restuarant situation- thus releasing those magical sugars and taking away the boiled onion taste.
Once again- love the feedback and great advice on here!
Phil

well thanks guys- question answered,looks like the concentrated base has already been done by razor-who seems to have a good reputation on here!
So thats me sorted, slow cooked concentrated base next time-cant wait!
Phil

Phil-I was coing to add the caremelised onions instead of raw onions to the base sauce recipe-I made a dopiaza the other night using caramelised onions and it was superb-I use bunjjarra paste in my curries too- which are in effect spiced caremelised onionns
phil

I keep wondering why base sauces have to have so much liquid in them-I realise that in a BIR environment, they have the luxury of having a big pot of the stuff on the stove top, and of course they have the turnover so they don't have to freeze the stuff like most of us mere mortals do.
My thinking is that a base sauce for domestic use could be made with a much reduced quantity of water in. This as I see it would  the following benefit of taking up far less storage space in freezer.
All you would have to do is thin the base to required thickness using either hot water, or better still veg/chicken stock-In fact a lot of base sauces have quite a thin consistency which has to be reduced in many cases by simmering at the cooking stage-with a thicker base you wouldn't need to reduce.
you could theoretically make a base sauce paste?
Any thoughts on this folks?
Phil

I too have been thinking about the sweetness thing that razor mentions_ I cant help felling that boiling onions for an hour or so which is what most base sauces call for will result in a slightly bitter base, unless sugar is added as an extra.
Infact the base sauces I've made have always had an underlying 'boiled onion' flavour which isn't particularly nice in my opinion and only gets lost by generous use of spices in finished curry.
I've done a bit of reading up on the chemistry of onions(given that onions are the major constituent in base sauces)and onions have their own sugars- you just have to cook them right to release them.
For my next base sauce I'm going to caramelise the onions first by slow frying for around 40 Min's (probably with garlic too as this is a form of onion) then add caramelised
onions to the remaining base ingredients will then slow cook overnight in crockpot on low.
What I'm hoping to achieve is the removal of the boiled onion flavour and addition of the onions natural sweetness-what are your thoughts on this?
Phil

I always use tamarind  paste in the little tubs-it like indian marmite!
I cant be doing with the faff of boiling the blocks.
hope this helps
Phil

From what I've seen on 'posh' cooking sites cassia bark is regarded as poor mans cinnamon- its certainly a lot cheaper, I accidentally bought a bag last week- it was marked as Cinnamon sticks- only when i got it home did i notice  in very small letters it said Chinese cinnamon sticks( the Chinese bit was in very small letters) and it turned out to be cassia bark.
I don't think theres a huge diff between the two personally- especially in a curry, where theres all sorts of other spices fighting for competition.
As for weighing it- well i just would guess,its not as powerful as proper cinnamon,have a guess is what i usually do!

Re quantities-
having experimented try these quantities(you can always adjust to suit your taste)
This will make enough for 2 people(or one greedy person)
all quantities are approx

100ml mango pulp/juice
1/4tsp coriander leaf finely chopped
1/4tsp mint leaf  finely chopped
1/4 tsp red chilli powder
1/4 tsp tamarand(go easy on this- too much makes the sauce dark brown!)
red food colour-a pinch should be enough

mix and leave in fridge for 30mins or so to let the flavours come out
-you can adjust thickness with a little water if required.
As I said im my previous message this is my first attempt- you can adjust quantitiies as required and add sugar and salt as well(although i dint find i needed it)

Hope this helps
Phil