How Long Can You Leave An Open Jar Of Jam On The Counter?

A sticky, scrumptious spoonful of jam can bring a little bit of magic to your breakfast no matter the season. But those heavy glass jars can take up a lot of space in the fridge and make the jam too firm to spread. You might be tempted to smear some strawberry preserves on your toast and then leave the jam jar right on the counter. After all, you picked it up from the pantry aisle of the grocery store. It should be shelf-stable, right?

That's not always the case. Popular brands like Smucker's and Bonne Maman recommend their jams and jellies be refrigerated after opening, but these companies don't specifically mention what will happen if they aren't. The USDA recommends a general 12-month period for storing unopened jams in your pantry and 6 months for storing them in the fridge after opening, but it's always advised to consult the "best by" date on any particular item first. After all, you don't know how long that case of jam was sitting in a warehouse somewhere.

When stored above 40 degrees Fahrenheit — the threshold for most bacteria growth — jam starts to get a little tricky (per National Center for Home Food Preservation). It can develop a funky odor, be infected by bacteria, or grow mold on the surface. And you can't just scoop off the fuzzy top and go ham on the remaining jam because invisible tendrils of mold can infiltrate the entire container, making it an absolute no-go, according to the USDA.

The good thing is that unrefrigerated jam probably isn't the cold-blooded killer you're afraid it is. The high acid content of the berries and grapes used to make jam puts it at a low risk for botulism, which thrives in alkaline conditions (via Saveur). But just because a bad batch of jam won't kill you, doesn't mean it'll make you stronger. Salmonella, E. coli, and other bacteria can still turn a delicious meal into an untimely episode of common food poisoning if you don't follow the best practices when it comes to expiring or expired foods.

According to Cake Decorist, your jam should be safe to eat for about one month after opening. "Refrigeration can extend its shelf life by a few months, but because jam has a pH level of 3 (bacteria grows most in pH levels of 6.5-7), there's no harm in storing it in your pantry," explains Eric Sieden, director of nutrition and food services for Glen Cove, Plainview, and Syosset Hospitals in New York (per HuffPost). 

Water activity is another factor that plays into food safety. The higher the water activity, the more prone food is to cultivate mold and bacteria, and jam's water activity is far below that of perishable goods like meat, milk, and fresh fruit (per a study conducted by Public Health England).

Storing your jam in a cool, dark place will increase your chances of it lasting long enough to make it to your next family brunch. Avoid shelves close to radiators or windows, and make sure you give it a good sniff before you dig in.