I was standing in the kitchen making dinner when my grandma suddenly walked in and froze. She stared directly at the cast iron pan sitting on the stove and looked at me with complete shock. I laughed and asked what was wrong, thinking maybe I had burned something. Instead, she slowly pointed at the pan and asked what I was cooking inside it. I told her proudly that I had been experimenting with all kinds of different meals lately.

She pulled a chair closer and shook her head. “You can’t cook just anything in one of those,” she said seriously. I looked at her with confusion because I had always believed a pan was just a pan. As far as I knew, if food fit inside it, then it could be cooked there. Apparently, according to her, I had been making a mistake without even realizing it.

Then she started explaining the first thing she avoided: highly acidic foods. She said things like tomato-heavy sauces and dishes with strong amounts of vinegar could sometimes affect the surface of a traditional cast iron pan. Next came delicate fish because certain smells and flavors could stick around longer than expected and affect later meals.

Finally she mentioned sticky sugary foods and desserts. She claimed they could become difficult to clean and sometimes create frustrating messes if not handled correctly. I sat there listening carefully because I had never heard any of this before. Suddenly I started thinking about all the random things I had cooked over the past few weeks.

By the end of the conversation, I realized I had learned more in ten minutes than I had in months of cooking alone. Sometimes the people who spent years in kitchens discover small lessons that never appear on packaging or instructions. And apparently grandmas always seem to know them before everyone else does.