Confusion about floor of cob oven
I would like to build a cob oven and have watched and read about several methods of doing it. One method said you have to build it on top of a bunch of empty wine bottles so that the floor of the oven doesn't steal the heat. Where as other methods build it right on the ground. Wouldn't building an oven first over bricks/stones or on the ground steal the heat from the oven? I am just curious why other methods haven't mentioned the wine bottles.