Here's How Long Pesto Should Be Good For After Opening
When it comes to pesto, a little goes a long way. The blend of garlic, basil, and pine nuts packs a burst of flavor with every small scoop added to creamy pesto pasta dishes, well-seasoned sandwiches, and more. Most recipes don't call for a very large helping of pesto, leaving the rest of the unsealed jar to wait until the next time it's needed. Unfortunately, pesto does not have a particularly long shelf life after it has been opened.
A sealed jar of pesto will typically last between four and six weeks in your pantry, with the exact "best by" date depending on the brand and type of pesto. But once you crack open a jar of the store-bought sauce, it's best to only keep it around for up to five days in the fridge. While you won't see any unappetizing mold build-up for at least a few weeks, you may notice a difference in flavor after just 72 hours. Luckily, there are ways to elongate its shelf life and prevent tossing yet another half-full jar of tasty pesto before its time runs out.
Pro tip: keep your pesto extra cold to preserve its flavors
Just like any pasta sauce, it is best to store your pesto jar in the fridge after opening. While your pesto can safely reside in your pantry until its first use, forgetting to refrigerate it after opening is guaranteed to spoil it long before the five-day mark. It's also best to seal and refrigerate your jar of sauce right after using, as exposure to oxygen can speed up the spoiling process. Make sure it doesn't sit on the counter for too long after opening, which can alter its flavor before you get a chance to properly chill it.
If you're hoping to extend your pesto sauce beyond its five-day lifespan, you can always stick it in the freezer. Opened pesto that has not yet reached the five-day mark can be frozen for up to six months without going bad or developing a drastic change in flavor. There are two different ways to freeze pesto. You can portion the sauce into cubes by filling an ice cube tray to freeze and use only the cubed amount you need for recipes. A standard tray holds about one ounce of liquid per cube, which will make for easy reference when deciding how much pesto you need to defrost. You can also freeze your remaining pesto in a glass jar if you plan on using the entirety of your leftovers when it thaws.
Does homemade pesto have a different shelf life?
If you are someone who prefers to prepare things by hand instead of reaching for pre-made sauces, you can always make your pesto at home. The results will undoubtedly be fresh and satisfying, but the storage process for your leftover pesto is different from a store-bought jar.
Many of the ingredients in traditional basil pesto have a high percentage of growing bacteria due to their low acidity levels. This means that certain food-grade preservatives are likely added to many of the store-bought brands to ensure the sauce does not spoil while sitting on the shelf. While homemade pesto will be free of any added chemicals and preservatives, this also means it will not last as long as the pre-jarred alternative. After preparing, your homemade pesto should be immediately stored in the fridge where it will last for up to four days before you notice a drastic shift in taste and possibly smell. You can, however, safely freeze your homemade pesto for up to six months to elongate its freshness.