After taking a look at the history of the tandoor, it would be interesting to know how it is made, how it functions and essentially, how can cater to all tastes.
Basically, the tandoor works on the same principle as the oven. The biggest advantage it has, and this is over the oven also, is that it provide completely wrap around heat, because of its construction. By controlling the draft and the fuel, it can be heated to up to 400 degrees centigrade, a feat that no other traditional coking oven can achieve.
It uses chopped dry timber as fuel and is made from clay free of any silica content (or mud), some grasses for pliability, along with some binders. The drum shaped oven is open at the top and has an opening about 10 cms across at the bottom to remove the ashes and also allow circulation of air.
The oven itself is either built in sections; wherein cylinders of a certain width and height are put together in layers and then gelled into each other to get the whole oven, or a coil is used to make the whole cylinder in one go. Either ways, it takes a lot of smoothing and then internal curing to make sure that it doesn't crack on drying, and also that no breads or meats stick to its internal surface while cooking.
Traditionally the tandoor uses non-smoky, non-resinous wood. In modern times, charcoal is the easiest to use fuel. Coke though, is never used inside the tandoor since it has high sulfur content. While cooking, sometimes twigs of aromatic herbs are added to the fuel during cooking, and these impart subtle flavors to the food inside. Charcoal heat inside itself adds to the flavor of the meats and breads cooking inside, and these herbs make the whole thing even better.
To bake breads, the dough is fashioned into round flats and stuck to the sides with a hooked stick or even bare hands. When it is ready, if falls off and can be collected. Meat is usually skewered and stuck into the oven, periodically tested for tenderness, and then the skewers or long sticks are taken out. Sauces and gravies are usually served separately.
The latest version of this age-old implement is, interestingly, a tandoor run by gas. This variation is made of special iron ally steel and is run on the principle of hot air circulation. Experts have pronounced it to be as effective as the traditional version, but purist still swear by the flavor of burning charcoal that the clay tandoor gives... and the gas tandoor cannot!!
The uses of tandoor have been appreciated across the East Asian belt, as we know. Afghanistan and the western Pakistan-Indian areas use the tandoor for their daily cooking. Indeed, in Afghanistan, huge naans (unleavened breads) are made by the womenfolk for their families that usually consist of twenty or more members. As far as Egypt, men use the tandoor to bake the bread, the only difference is that their tandoor is buried into the sand, while in India, it is usually buried inside a raised platform, with only the top opening showing.
The Chinese use porcelain ovens, very much like the tandoor, to make their famous Peking Duck. This porcelain is made with clay that is found only in that region. In Iran, the oven is called Tanoor and is even today, used to bake breads, the popular ones being called berbery, sangak and lavash..almost as regularly used as flour bread in the rest of the world. In other Arab countries too, makeshift tandoors are made wherever clay and twigs are available , and breads are baked sticking to the sides of the oven. Sometimes, a pot of meat curry or meats is also cooked inside the same oven along with the breads...a most primitive, yet efficient method of getting a meal ready.
While baking various types of breads in the tandoor has been done since time immemorial, meats can be cooked in the tandoor only after tenderizing. Only tender meats can be fully cooked in it, since there is no provision for braising, sautéing or broiling. Traditionally, in India at least, meats were not cooked in the tandoor. The only exception that history throws up is the meat of the still born lamb of the variety burrah karakul, which was possible because it was so tender. The regular flesh needs tenderizing for at least 6-8 hours before plunging it in the tandoor. Fortunately, the Indian spice tradition has the solution for this and the result is there for the entire world to see, taste and admire.
Some of the best traditional tenderizers used in tandoori cooking are souring media like lemon and pomegranate juice, yogurt, pungent condiments like ground mustard. This information can be found in the medical treatise of an ancient Indian physician, Sushruta, dating back to the fourth century AD. He lists out these tenderizers for cooking meats, thereby making them a wholesome diet with tissue building properties.
Today we know that some of the best tenderizers are raw papaya, yogurt, raw pineapple, and sometimes, even vinegar. Of course, the one to use will depend on what flavor the dish is planned to be, for in Indian cuisine, there are no hard and fast rules, the personality of the dish almost always reflects the expression of the person cooking it.