Beef Noodle Soup In Bangkok Has Been Simmering For 45 Years : The Salt : NPR | INTELLIGENT WORLD TODAY |
"Lots of people think we never clean the pot," he says. "But we clean it every evening. We remove the soup from the pot, then keep a little bit simmering overnight."

It's that little bit, he says, that forms the stock of the next day's soup. So, yes, at least a taste of what you put in your mouth is 45 years old and counting.