Most of the material is ceramics with only one wooden spoon. Wood also can survive without decay if it is in an environment without oxygen. Also, the kitchen is

Most of the material is ceramics with only one wooden spoon. Wood also can survive without decay if it is in an environment without oxygen. Also, the kitchen is stated as part of the underground part of the house, a.k.a it might've been in a basement or a semi-basement and it is easier to fill it with soil compared to if it was above ground.