If you use ketchup at home, you probably store it in the fridge, right? After all, the bottles themselves say the condiment needs to be refrigerated. So, why isn't restaurant ketchup refrigerated? It's not because they're using a special kind of ketchup—it's because they're going through it a lot faster.

It turns out, it's totally fine to keep ketchup at room temperature, but keeping it in the fridge will preserve its shelf life—something that's a lot more important for people at home than for restaurants. Restaurant ketchup doesn't have a long lifespan in the first place because it's used so quickly, so long-term freshness isn't really a concern. Household ketchup, meanwhile, is a different story. Here's the truth about why restaurants don't refrigerate ketchup.

Does restaurant ketchup need to be refrigerated?

Despite the messaging on the label, ketchup is actually shelf-stable. In fact, Kraft and Heinz have an official statement declaring so.

"Because of its natural acidity, Heinz Ketchup is shelf-stable," the company's website explains. "However, its stability after opening can be affected by storage conditions. We recommend that this product be refrigerated after opening. Refrigeration will maintain the best product 'quality' after opening."

There's nothing wrong with restaurants keeping ketchup bottles on the table. The product is shelf-stable, and restaurants go through it pretty quickly. Think of how many people use ketchup on their burgers and fries!

Should you keep ketchup in the fridge at home?

Even though Heinz admits that ketchup is shelf-stable, there's a good reason you might still want to keep it in the fridge. As restaurant employees explained on Quora, they go through ketchup way faster than you will at home.

Think about it: How many times do you use ketchup in your at-home meals? Once or twice a week, at most? A restaurant, on the other hand, might use the same amount of ketchup in a day that your household could take weeks or even months to use.

Keeping ketchup in your fridge at home is a smart move to preserve the condiment's shelf life and keep it fresh. Sit-down eateries don't need to worry about that as much, as they have a high rotation of diners seasoning their food with the restaurant ketchup. But given the average family's much-lower ketchup usage, keeping the condiment in the fridge makes more sense.

RELATED: The easy way to make healthier comfort foods.

What about mustard?

OK, here's where it gets a little tricky: It depends on the type of mustard. According to French's, Dijon and horseradish-based mustards need to be refrigerated. Other types of mustard, like ketchup, are shelf-stable, but you might still want to keep them in the fridge if you're not using them that often.

"Dijon and Horseradish mustards will lose their distinct flavors if not refrigerated, so we encourage refrigerating both," the French's website states. "For all other mustards, refrigeration will help maintain flavor; however, it is not necessary to refrigerate if you prefer to consume your mustard at room temperature. There are no ingredients in mustard that spoil."

If you keep ketchup and mustard in your pantry, rather than in your fridge, they're probably not going to go bad, but keeping them refrigerated could extend their shelf life. After all, your home's condiments will be on the shelf for way longer than that restaurant ketchup will be.