Historically, kitchens weren’t luxurious and unlike today’s kitchen, they were not rooms where people wanted to spend time in. They definitely weren’t rooms meant for hosting guests or entertaining. They were dark and prone to catching fire; they were filled with noises, messes and smells.
They were extremely busy spaces and could be hot and uncomfortable. For these reasons, kitchens tended to be situated as far away as possible from the social or private rooms in a home. The upper class even celebrated a disconnection from food and food preparation by situating their dining rooms far away from the kitchen, going so far as to mask the smell of food. Even the lower classes placed the kitchen away from the center of the home by moving them to the back of the house, next to the outdoor work areas.
Source: Porch.com