There are a huge number of tandoor oven types available in market but for commercial purposes we can divide them mainly into two types.
Traditional Clay Tandoor Oven – Traditionally the tandoors are made of clay. These are bell shaped clay pots with insulated outer layer. Hot coal or fire is used to heat this pot which rises the temperature of the air inside the pot. The food is placed inside these hot pots or tandoor ovens with the help of skewers and food gets cooked to the perfection with circulating hot air inside. The spicy smoke and dripping juices on coal that turns into fumes give the food a unique flavour and aroma that make the dish a tandoori dish. As these are authentic Indian tandoors many restaurants still prefer these types of ovens but these are perfect only for outdoor cooking.
Modern Tandoor Ovens – As almost all restaurants do indoor cooking you will find modern tandoors in these restaurants. These tandoor ovens are designed especially for commercial purposes and are available in two types, electrical and gas tandoor.
There are many reasons why most of the restaurants prefer modern tandoor ovens over the traditional ones. It is true that there is nothing like food cooked in traditional tandoor but these tandoors are unsafe for indoor cooking while in most of the restaurants, the cooking area is indoors. The second main reason is these modern ovens are designed for multipurpose usage which means one tandoor can prepare many dishes at one time along with tandoori dishes. These tandoors are easy to use, long lived and much safer in comparison to the traditional ones.