A tandoor is a traditional Indian clay oven, with rounded sides, standing about 5 feet high, used in cooking and baking. The tandoor is used for cooking in a number of countries other than India like Azerbaijan, Turkey, Iran, Pakistan, Afghanistan, the Balkans, the Middle East, and Bangladesh etc.
The oldest examples of a tandoor were found in the Harappa and Mohenjo Daro settlements of the ancient Indus Valley Civilization. In Sanskrit, the tandoor was referred to as kandu. The tandoor was popularised during Muslim reign in South Asia.
Pre-fired clay tandoori oven [Image source]
A mobile clay tandoor oven and its cross sectional view showing the clay pot arrangement in an outer steel casing with castors.
The tandoor oven relies on the natural cooking medium - "charcoal". The intense heat inside, created by the hot coals cook the meat, seafood or chicken pieces very quickly. The food becomes crispy on the outside while remaining juicy inside. The tandoor is used for cooking certain types of Iranian, Afghan, Pakistani and Indian foods. Tandoori chicken, chicken tikka and bread varieties like tandoori roti and naan which are very popular in the Indian cuisine. The word tandoori means "pertaining to the tandoor" and is used to describe a dish cooked in a tandoor. Tandoori cooking does not use much oil or ghee and therefore is preferred when one is pursuing a low calorie diet.
It is believed that, it is the charcoal fire in the tandoor that gives the food its smoky flavour which cannot be replicated any modern oven. It is also impossible to create the exact flavour and texture of tandoori foods without a tandoor oven.
A tandoor in use - making naan and baking meat and vegetables on skewers.
The heat for a tandoor was traditionally generated by a charcoal fire or wood fire, burning within the tandoor itself, thus exposing the food to live-fire. Cooking temperatures in a tandoor can approach 480°C (900°F), and it is common for tandoor ovens to remain lit for long periods to maintain the high cooking temperature. The tandoor design is something of a transitional form between a makeshift earth oven and the horizontal-plan masonry oven.
A traditional tandoori oven has to be seasoned. A paste is made of spinach and applied to the inner surface and left to dry. An emulsion of mustard oil, buttermilk, jaggery and salt is applied over the spinach. A small fire is lit and the temperature allowed to rise gradually until the emulsion peels away from the walls of the tandoor. A brine solution is sprinkled on the inner walls to facilitate the sticking of breads like naans to the sides. To know if the oven temperature is optimum a naan is stuck to the sides, if it falls off, the oven is not hot enough. It is important to marinade the meats and paneers( cottage cheese) cooked in a tandoor as the process is very drying and also to impart flavours.
In India, the tandoor is also known by the name of Bhatti.
The tandoor is a very important fixture in many Indian restaurant kitchens around the world, as it is very versatile and can be used as an oven and a grill. The flavour that it imparts to the food from the hot charcoal is very delicate and delicious. Some modern day tandoors use electricity or gas instead of charcoal.