Topic: DIY tandoor build and test-firing

[George]

After one or two years of delay after delay, I finally built a home made tandoor today. My objective is to do this as cheaply as possible, both in terms of the cost of materials and the effective cost of land taken up. I decided to build a 'portable' tandoor using bricks which are easy to erect and easy to dismantle after a cooking session. I don't want such an ugly item as a tandoor to have a permanent place in my garden.

I'm relaying some paving slabs down an alley at the side of my house at present, so seized the opportunity to use the land there. Who needs a special base made of fire bricks? I decided to scatter a bit of sand to help level things out and start building on soil/clay with no special base at all. Could that have been a mistake. not having a 'proper' base? I doubt it, but read on...

I'm using magnetite bricks from a couple of old electric storage heaters. They stack up quite well owing to the square edges and they are obviously designed to be happy with heat. The total cost of ALL my materials for the tandoor was about GBP5 and most of that was petrol to go and collect the storage heaters from a friend. I also decided to add a blower/fan system to provide a bit of air flow. The six small fans came friom old computers and can be powered from a 12 volt car battery.



Here's the finished item, which took about 1.5 hours to 'design and build'.



I'd started it off with newspaper, twigs and small dry branches. Flames leapt out of the top and I feared the fence might catch fire. Then I added 2 bags of charcoal (10Kg) and eventually it quietened down and all the charcoal seemed to be making a contribution. Most of the activity was near to the air intake vent, not surprsingly.



I put a lid on top with insulation (not pictured) to try and build up heat but my oven thermometer indicated a temp of only around 250C after 2 hours, even in the lower half of the oven.  Perhaps the storage heater bricks 'suck out' too much heat. HestonB said on TV that he used 10 bags of charcoal to get the temp up to his target of 370C using refactory bricks, I think he said. That's crazy! 10 bags would normally cost about GBP30. I paid 75p each for 2 bags in an end-of-season sale.

First I tried cooking chicken tikka on a long rod I'd made to resemble the type of thing the BIR's use. This cooked for 10 mins, not far above the charcoal but was only just cooked. All the signs are that I have failed to produce anywhere near sufficient heat. How can that be with 10Kg of charcoal glowing away, with a turbo fan, and the lid on to retain heat? Anyway, the tikka was fine but no better than if I'd cooked it on my gas cooker.

Next I tried cooking some naan bread. It stuck to a marble slab I'd dropped into the oven, to provide a clean, flat surface, but it simply would not cook. It was a joke. Back to the drawing board...total failure. Here's a photo after the dough had been in the oven for about 10 minutes!



I'm going to rearrange the bricks into a completely different layout, add some insulation all round and try again.

 

[Jeera]

George, that nan bread looks depressed down there. 10 out of 10 for the experiment though :-)

[martinr1000]

hi

lumpwood charcoal would probably help as it burns really hot. judging by the size of your tandoor it probably needs and absolute load of charcoal to make it work properly. my little tandoor needs a couple of kilos of charcoal just to get it started and then a few more kilos of lumpwood to heat it up. i would suggest at least a 5 or 6 kilo bag of briquettes followed by a 6 kilo bag of lumpwood for yours judging by the size of it.

i would say that if the naan is sticking then the walls are actaully hot enough it's just the interior heat thats lacking.

just one more thing but you might want to angle the wall at the top inwards so there is more of a funneled heat effect.

in terms of insulation then maybe you need to skim some concrete over the outside of it.  

probably doesn't help much but it's my two penneth worth anyway.

cheers

[George]

George, that nan bread looks depressed down there. 10 out of 10 for the experiment though :-)

Jeera - thanks for the marks for effort, a bit like grade A effort and grade E attainment at school! I'm just relieved I hadn't spent days putting something more permanent together, only to discover it didn't work. Most people use fire cement but I doubted if a few gaps would matter. The fire has to breathe somehow so the cracks are my exhaust vents. The naan was flatter when it went in. By the time that photo was taken I'd picked at it a bit for a taste. Even though not cooked, the flavour was not 'smoked' or anything special, despite there being plenty of smoke in the oven.

I WILL get there in terms of generating an oven which gets up to 500C. This first attempt is just a stepping stone.

[George]

lumpwood charcoal would probably help as it burns really hot. judging by the size of your tandoor it probably needs and absolute load of charcoal to make it work properly.

Many thanks for your suggestions. I had more brickettes than lumpwood charcoal in stock but I didn't realise there was a different burning temperature, so I've learned something. I would have added the lumpwood for potentially better 'flavour' but never got to that stage. I must now search out end-of-season supplies of lumpwood charcoal.

I'm sure you're right about the oven size. Perhaps it's the pure physics of the energy required to heat an oven of that size, especially if it's not insulated. My next attempt will be smaller and insulated. My oven can't be much larger than a BIR tandoor, though, can it? How much gas or charcoal do they use?

[Curry King]

WOW, great stuff George, may only be a quick knock up but it's further than I have got.  I can't wait to see mark 2 

[Yousef]

George,

Amazing work and a great read, cant wait for part 2.

Stew

[haldi]

Sorry it didn't work out George
Best of luck with the modifications

[George]

I guess a temperature of up to 250C wasn't too bad given that gas mark 8 is 230C and very few domestic ovens get hotter than that. If I'd never heard about tandoors using charcoal, I'd really wonder if it's the best fuel. I mean barbecue food is notorious for being an undercooked health hazard, even when meat and other foods are positioned on a grille just a few inches above the glowing charcoal.

Another type of old fashioned oven is wood fuel based as in some bread and pizza ovens, so my next attempt will lean towards that, partly in the hope of achieving a significantly higher temperature. What are we aiming for here? I suggest it's (a) high temperature and (b) the aroma/smoking effect which is said to come from charcoal and/or wood. That's all. Some people disagree and say gas-cooked food tastes just as good, on a barbecue for example. I simply don't believe that more than 1 in 100 BIRs can use anything other than gas, electricity or possibly oil as a heat source. Charcoal or wood would surely be far too impractical for a restaurant. So wherever the best BIR tikka or naans you've ever tasted came from, I bet they were cooked in a gas fired tandoor!