Topic: 18hr Slow Cooker Curry Base, Double Concentrate

[natterjak]

No, it's not a typo in the subject line - this is really a curry base which takes 18 hours to cook...!    So why would you be interested in making this then?

- Convenient... Yes, even with an 18 hr cooking schedule this is a convenient recipe because the vast majority of the time the cooking is completely unattended.
- Low stress.... because the cooking is so slow it's hard to go wrong.  You won't burn anything, over evaporate, etc. and if you're busy when the base is done, just leave it cooking till you're ready.  It won't spoil.
- Truly excellent results.... Using this curry base I've finally achieved the sweetness of flavour and texture I've been looking for in my curries for ages.  The slow cooking technique seems to cook the onions in a very delicious way.

The recipe uses a 6.5 litre slow cooker (crockpot), loaded to the brim with ingredients and cooks to a double concentrated outcome, meaning you can freeze into portions and add equal quantity of water to curry base when you defrost to achieve the correct base sauce consistency.  This makes it very space and energy efficient for freezing versus normal "fully dilute" curry base.


6.5l Slow Cooker such as Morphy Richards 48715

The timings may be summarised as follows using 1 hyphen per half hour:

|--|  1 hour initial prep, loading slow cooker
|--------|  4 hours slow cooker on high, bringing everything up to temperature (unattended)
|------------------------|  11 hours slow cooker on low (unattended)
|-| Switch off allow to cool for 30 mins
|--| Blend mixture, sieve base, return to slow cooker
|----|  2 hours on high to come back up to boiling temperature (unattended)
|--| 1 hour final boil until oil separation and final flavour achieved (attendance required to skim and stir).

The idea is to commence the cooking at a time which means you will be around to provide input at the necessary stages (prep, blending & sieving, finishing stages).  For most of the cooking there is no user input at all, not even the occassional lift of the lid to give it a stir.  Indeed opening the lid of a slow cooker can release a lot of heat which takes time to get replaced and interferes with the cooking.  Just be brave and leave it alone!

I suggest you begin at 6pm with prep, so the cooking begins at 7pm and you can switch down to low setting at 11pm before retiring to bed.  Next time you need to go back to it will be at 10am the following day (nice lie in!) and cooking will be fully finished by around 2:30pm, leaving time to it to cool and be portioned up, fridged overnight and frozen the next day. 

Although adapted for slow cooking, the basic recipe is closely based on Chewytikka's 1hr and 3hr base recipes and also borrows from the Zaal base recipe, so due credit to Chewytikka and Az 

Ingredients
For the initial cook in the slow cooker:
- 3kg onions, peeled but left whole.  It's about 25 medium onions, or as many as will almost fill the slow cooker to the brim.  (other ingredients will mostly fit around the onions and into the space under the lid)
- 100g frozen sliced carrot, or 1 large carrot peeled and sliced
- 120g frozen sliced cabbage or one third of a fresh cabbage sliced
- 1 medium potato peeled and sliced
- 100g coriander stalks (stalks from a good big bunch of coriander)
- 100g green pepper / capisicum (the flesh of 1 medium green pepper less seeds and core)
- 1 litre water
- 1 mug full of oil (veg or sunflower), approx 250ml to 300ml
- 3 level tsp salt
- 20g block of frozen garlic puree (or substitute fresh)
- 20g block of frozen ginger puree (or substitute fresh)

For the frying stage:
- 2 chef's spoons oil
- 1 chef's spoon garlic/ginger paste
- half chef's spoon mix powder
- half chef's spoon haldi (turmeric powder)
- 1 tsp chilli powder
- 4 chef's spoon passata

For the Akhani (spiced water)
- 1 litre water
- 3 asian bay leaves (tej patta)
- 7 cloves
- 1 black cardamon
- 6 green cardamon
- small piece of cassia bark

Directions

Load the slow cooker with the peeled whole onions (cut off top and root of onion) and tesselate carefully to fit the max. onions into the space.  Add the sliced carrots and sliced cabbage, encouraging these small ingredients into the gaps between the onions.  Pour in 1 litre water and 250 to 300ml oil (large mug full).  Add sliced potato and green pepper plus coriander stalk at the very top of the pot.  pop the frozen garlic and ginger blocks into any remaining space.  It's probably a tight squeeze and if necessary take out an onion to fit it all in.  The ingredients will relax and settle during cooking and if necessary you can weight the lid of the slow cooker to keep it down firmly at the start of the cooking.  Note.. the liquid does not cover the ingredients nor is intended to.  The long slow cook allows the heat to fully penetrate and cook the ingredients, even those at the top of the slow cooker out of the liquid.  Also additional water will come from the onions during cooking so the liquid level will rise.


Nearly fully loaded with onions


Everything except coriander stalks and potato

Switch the slow cooker on high setting, make sure the lid is fully seated and leave it alone for 4 hours.  After 4 hours it should be nicely bubbling at the edges.  Switch to low and retire for 11 hours.  Do not go fiddling with the slow cooker, lifting the lid, etc. during this 11 hour period! 


Fully loaded, at start of 4 hour initial cook


Towards the end of the 11 hr slow cook

After 11 hrs on low, switch slow cooker off and remove lid to allow to cool prior to blending.  You can lift the crockpot insert out of the slow cooker to aid the cooling.  Then use a handblender to thoroughly blend.  There will only be just enough liquid to allow blending at this stage, so give the blender time to do its work and rest the blender every few mins to prevent overheating.  When blended smooth, place a metal sieve over a large (6 to 8 litre) stockpot and pass the base through the sieve in batches.  Use the back of a spoon and a stirring motion to encourage the base through.  Ultimately you'll be left with a large clump of onion fibre which won't pass through and an aching arm.  Ignore the arm ache and throw the onion residue in the bin.  Check out Chewytikka's 3 hour base sauce video for an illustration of this process and don't skip it, it really enhances the texture of the base and removes some bitterness too.

Give the now empty slow cooker crockpot a quick rinse then decant the sieved base back into the slow cooker and put back onto high heat for 2 hours to bring back to boil.  Meanwhile get some akhani underway and fry spices in tomato paste (both processes described separately below but you can do both at the same time)

Akhani

Pour 1 litre cold water into saucepan and put onto high hob to warm to boil.  while warming put the whole spices listed in(crush the green cardamom a little to open the pods)  Ingredients in the pan.  When boiling turn down and simmer for 10 to 15 mins then pour through a sieve  into slow cooker to add to the sieved base, (ie. Whole spices don't go into the slow cooker mix). Stir well

Fried spices

Put a non-stick frying pan onto high heat with the oil and when very hot add garlic ginger paste and fry for around 1 min till not spitting and slight colour change.  Add mix powder, turmeric (haldi) and chilli powder and fry till cooked (around 1 min) when you should smell a toffee like aroma.  It's not necessary to singe the spices, just make sure they are cooked but not necessarily on the edge of burning.  Now add the passata or diluted tomato puree and fry again till reduced and darkened slightly.  Add this complete mix into the slow cooker and stir into sieved base.

Taste the slow cooker contents at this stage.  It's interesting to taste before and after the addition of the akhani to understand the added "zing" from the spiced water.  It should taste primarily sweetish and mildly spicey but you will probably find at this stage that there is still some bitter aftertaste present.  This will cook out in the final cook.  After the first 2 hours on high setting have elapsed the slow cooker contents should be visibly boiling and a scum may have started to form.  Leave heat setting on "high" and cook for at least another hour.

As and when scum forms, remove it by skimming.  Then stir the sauce and quickly replace slow cooker lid to prevent excess heat loss.  During this final hour of cooking stir every 20 mins and pay attention to lifting from the bottom of the cooking pot the sediment.  Stir it back through the sauce to reincorporate.  Each time you stir, taste the sauce and note how the subtle bitter aftertaste reduces and disappears.  After about an hour a rich dark oil will have separated as per photo below.  Now the sauce is done but will require another final stir to reincorporate the oil and lift sediments from the bottom of the pot.  At this stage switch the slow cooker off, lift the pot out of the cooker and leave to cool with lid off.


Fully cooked double concentrated curry base sauce

Freeze into portions of 175ml (single curry) or 350ml (two curries).  When defrosting, pop the frozen base into a small saucepan with equal quantity of fresh water and heat/stir together to defrost and warm back to the boil. 

[solarsplace]

Hi NJ

What a tremendous post! absolutely superb  effort.

Must give this a try. Thanks for taking the time to thoroughly document and present this.

Regards

[PaulP]

What a great post NJ,

Very interesting stuff and I'm glad to hear it tastes great for you.
Sadly my slow cooker is far too small for this! And I've already committed about 200 quid to my forthcoming "sous vide" meat cooking experiments, which I'll report back on when I get set up.

Cheers,

Paul

[chewytikka]

Wow, what a breath of fresh air NJ, fantastic post and thanks for the credit.
Great alternative method there, well done for sharing this for free, in keeping with the cR0 mission.
But no doubt it will turn up in a ebook, as a new curry secret somewhere down the line.
cheers Chewy

[Salvador Dhali]

I can only second, third and fourth the above comments, natterjack. Sterling work bordering on sheer genius.

My only caveat is that I don't own a slow cooker, dammit, so inevitably I find myself faced with further CRO-generated expenditure.   

(Cue the usual suspects with a raft of helpful suggestions tempting me to shell

[natterjak]

I can only second, third and fourth the above comments, natterjack. Sterling work bordering on sheer genius.

My only caveat is that I don't own a slow cooker, dammit, so inevitably I find myself faced with further CRO-generated expenditure.   

(Cue the usual suspects with a raft of helpful suggestions tempting me to shell

[natterjak]

Wow, what a breath of fresh air NJ, fantastic post and thanks for the credit.
Great alternative method there, well done for sharing this for free, in keeping with the cR0 mission.
But no doubt it will turn up in a ebook, as a new curry secret somewhere down the line.
cheers Chewy

Thanks CT. The core of the recipe is really yours, I've kept the ingredient proportions very similar just upped the onions and fried the spices & tomato rather than adding and boiling. Your ideas also helped me understand the contributions the akhani and sieving can make to the end result so thanks 

[natterjak]

Hi NJ

What a tremendous post! absolutely superb  effort.

Must give this a try. Thanks for taking the time to thoroughly document and present this.

Regards

Thanks Russ. Re, the thoroughness of the description it's just because I'm rubbish at being concise 

[Salvador Dhali]

I'll be happy if a few people try this at some point and delighted if you feel it's better than your normal base, but would certainly be nervous about people rushing off to spend money on new appliances just so they can try it.

No worries - I was just having a bit of fun. Besides, being a serial buyer of appliances I need no encouragement whatsoever!

Interesting to note that you've combined different base ingredients/techniques though Natterjak. My best bases of late have been born from a similar approach, but regardless of base I find using the second stage frying produces the most consistent results.

Right - I'm of the the kitchen dept at Amazon! 

 

[chewytikka]

Hi NJ
It's great to see how your currying and your understanding has developed since your few hours of real behind the scenes experience with Az at Fleet.
Can you imagine if you worked along side the team there for a couple of weeks! - The mind boggles.

Just read your OP again and I've got the exact slow cooker tucked away.(30 squid ASDA)

So I'll fill it up later today and there should be a nice aroma for breakfast. ;D
cheers Chewy