Heyman had spent his life in the main kitchen. He came in when he was 11, and the first time he got to touch the knife was at 18. Afterward, he spent 30 years to become the head chef of Kitchen One. He spent another 100 years in the main kitchen, and took over the role of the supervisor from his master. That made it 120 years in total.
The chief and nobility had an exceptionally high expectation for their everyday meals, so he could not afford to make any mistakes. The lives of hundreds of chefs from the main kitchen depended on him.
Entering the main kitchen was akin to going to jail. Unless you died or lost the chief's favor, there was no going out.
Heyman had been trying to innovate and create new dishes to come up with new flavors to satisfy the chief and nobilities' taste buds so that they did not get tired of the food.