To refrigerate, or not too once its open- that is the question!
Here’s Heinz’s official stance on the issue:
Because of its natural acidity, Heinz® Ketchup is shelf-stable. However, its stability after opening can be affected by storage conditions. We recommend that this product, like any processed food, be refrigerated after opening. Refrigeration will maintain the best product quality after opening.
It really comes down to your palate’s preference: Do you like it cold or room temperature? If you prefer it at room temp, then just make sure you use it up more quickly.
What’s next: Peanut butter? Mustard? Hot sauce? Pantry or fridge?