Do you prefer refrigerated ketchup or warm ketchup?

Cool, of course.

Refrigerated. Similarly, I do not want my tomatoes slices warmed when I put them on a sandwich or burger.

Taste wise, it doesn’t make any difference to me. I keep my ketchup in the refrigerator for safety reasons. When I know I’m going to be adding ketchup to a meal, I do my best to remove it early on & let it sit out for a little bit so it flows better when I use it. I find cold ketchup to be lazy & it tends to want to sleep in when I want to use it!!!

At home, once it’s opened, I store it in the refrigerator as per the instructions on the label “refrigerate after opening” but I prefer it to not be chilled because it cools off the food. I don’t use a lot of ketchip, either at home or in restaurants. A little dab’l do ya, as they say.

Room temperature is fine.

You must keep opened ketchup in the refrigerator. If you like, warm a little up before using on your potatoes or eggs or whatever. I’ve had food poisoning from unrefrigerated ketchup. Read the label; it does not stutter. REFRIGERATE AFTER OPENING RECOMMENDED. The “recommended” was added in recent years because of restaurant owner complaints. They don’t want to put a new bottle for every customer. Well, they should and that’s why I will not use condiments in restaurants….unless they can provide the little sealed take-away packages.

No ketchup. It’s gross

Same as @flutherother, although I think Scottish rooms are usually cooler than SoCal rooms. ;)

@SnipSnip

“You must keep opened ketchup in the refrigerator.”

I agree, and the same goes for mayo, even before it’s opened.
Actually, I store almost everything that’s been opened in the fridge, including bread, nuts, seeds, etc.
I just read that William “Refrigerator” Perry, stored everything in his stomach!* ;-o

*I read it, just after I wrote it.

@Brian1946 Correct. But when I buy ketchup I put it in the refrigerator and most of the time it goes in the trash with never having been opened. We rarely reach for it.