It's an age-old debate, do you store ketchup in the cupboard or refrigerator after opening?
Well, the Heinz bottle says it should be kept refrigerated after opening, so why do restaurants leave theirs sitting out on tables all day? Heinz says, "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." These instructions appear simple. Keeping this condiment in the fridge prolongs its longevity, right?
Yes, it will last longer when kept chilled, but this isn't really an issue at a restaurant dishing out fries and burgers all day. An eatery likely uses as much ketchup in one day as your family will use in weeks or months. Their ketchup will never get the chance to become "unstable." Cheatsheet does, however, say that the practice of "marrying ketchup" — pouring the remaining contents of several ketchup bottles into another — is more concerning, listing it as one of the grossest "things restaurants do to save money."
Heinz recently asked, "Where do you store your ketchup and the answer of "fridge" appeared to be the consensus, according to 63.2% of over 13,000 votes cast, the poll's results showed. Meanwhile, 36.8% of respondents said they preferred their ketchup in the cupboard.
For what it's worth, there are two bottles of ketchup in my household. Mine is stored in the fridge, and my wife prefers hers stored in the cupboard.