Topic: Home Tandoor Tips

[George]

The potential output of food from this thing is IMO quite impressive: 7 skewers of chicken say 2 breasts per skewer say 15 minutes cooking time? I think that's quite good. You could possibly get 5 or 6 naans on the go at any one time say 3 minutes each..... You do the math!!!
I will keep an eye on the fuel consumption but I think I used about ?5 worth of charcoal over about 5 hours

I'm really puzzled as to how the tandoor style ovens manage to get such good results, when I can't match it with my wood burning stove, whether using wood or charcoal. My stove will get so hot that it would be IMPOSSIBLE for anyone to put their arm in for the several seconds you usually see when people place a naan into a tandoor. Secondly, the tandoors are often seen used without the lid, so you'd think all the heat just shoots straight out. Perhaps the naans cook in the exhaust stream, so to speak.

Here's one of many examples on youtube:

Naan Bread in the Tandoori Oven

[Willyeckerslike]

Its a long time ago now when I was at college & the the beer has damaged what few brain cells I had... but I think the clay pot used in a traditional tandoor retains the heat whereas the metal in your prototype conducts heat, so the initial temperature would be the same and as the primary heat source (coals)subsides the metal would lose the heat to your lagging but the pottery would maintain a steady temperature.  For example you have been using a granite tile for naan trials? take it out of your oven along with a metal grill & see how long the granite maintains the heat compared to the metal grill.

I have been wrong before tho ;D

[mickdabass]

Willyeckerslike - that makes sense to me too. Ive been bringing the tandoor in at nights - worried that the frost might crack it and it is still quite warm the next morning

[George]

I think the clay pot used in a traditional tandoor retains the heat

That's right, of course. I tried to take all those factors into account and it still doesn't work.

>the metal in your prototype conducts heat

Yes, but the heat was stopped from going anywhere by thick insulation, just like in a tandoor. A clay pot would leak heat if there was no insulation in a tandoor.

>For example you have been using a granite tile for naan trials?

Yes, that's right - as a substitute for 1sq ft or more of the clay walls of a tandoor.

>take it out of your oven along with a metal grill & see how long the
>granite maintains the heat compared to the metal grill.

Of course, but the metal wasn't being used for cooking, i.e. in contact with the bread. I'm sure a granite slab would hold heat better than a clay wall.

I'm getting better results with my domestic oven now so I won't be tempted to buy a tandoor. Any of these charcoal-fired devices strike me as too much trouble, simply for baking naan bread. I may, however, try making a smaller stove for cooking tikka, where there could be advantages from (a) the very hot skewer and (b) juices falling onto charcoal, with the smoke then feeding back into the chicken.

[JerryM]

George,

i'd go along with you that your oven is too hot. i think with crucible molten metal might just be possible.

why i think this is from a disaster on the pizza front in my domestic oven. it's really working a treat now - i have quarry tiles on the 1st shelf and sheltering the thermocouple. anyway cut it short i moved the quarry tiles to the base of the oven - burnt pizza - i think the temp increased from ~550F to something like 700F.

what i'm getting at is this science is no easy thing and a few mods may well be all that is needed on your machine.

the 1 hr heat up of the tiles seems very critical - hence the prior comment on heat mass.

i'm on the lookout for a cheapo infrared temp as my analogue dial gauge is helpfull but does not tell the full story of surface temperature.

[George]

i'd go along with you that your oven is too hot. i think with crucible molten metal might just be possible.

Jerry - many thanks for your suggestions and feedback from your own experience. I tried placing a tiny copper pipe and some copper wire in the chimney of my stove where I assume the heat was at its most intense. The copper did not melt - not even slightly - which really surprised me. I then placed a thin strip of aluminium only 0.8mm thick in the flame stream. Eventually, an inch at the end fell off the end of the aluminium (melted away) which suggests a flame temperature of perhaps 700C but nowhere the 1000C+ required to melt copper. Some websites seem to suggest that wood flames may not be particularly hot. I placed a K probe leading to a multimeter in the chimney as well, and measured up to 475C in exhaust gas, but I didn't want to risk the K probe in direct flames. There must be something special about the design of a tandoor but, as I'm getting better and better results from my gas oven indoors, I'm now less bothered about using charcoal.

[JerryM]

There must be something special about the design of a tandoor

George,

many thanks for temp info - interesting. will let you know if i get anywhere with idea of outside combi oven.

interesting too on the "hotness" of wood -something i'd not thought of and need to dig a bit deeper. albeit i already know wood produces enough heat down to cooking tikka on chiminea. it must be down to the free air needed to burn efficiently, the need for this heat mass and the type of heat mass material.

ps i tried aluminium tray to cook pizza (to compare with black steel) and found it very poor. base was soft like bread yet topping over cooked. all interesting stuff.

[PhilUK]

The reason I think a proper tandoor get so hot is that it works the same way as a jet engine- the base where the charcoal is is wider than the neck- the heated air moves up the tandoor and accelerates, this causes a draw on the coals an the bottom and a superheating effect- hence it just gets hotter and hotter (400-500c).
Combine with this the radiant effect of the clay and bricks.
If you google how a jet engine works and imagine it stood on its end- the similarities are striking.
I may write to Richard branson and suggest he straps Tandoors to the wings of his planes.
Phil

[JerryM]

given PhilUK thoughts does anyone know how hot a tandoor gets - what i'm really searching for is how do you test that it's at cooking temp.

i've been reading up a few website on wfo (wood fired ovens) for pizza and one suggests chucking floor onto the stone and looking for how the colour changes.

[Peripatetic Phil]

does anyone know how hot a tandoor gets ?

Wikipaedia him say :
 

Temperatures in a tandoor can approach 480