First things first: Homemade pesto usually lasts about 4 to 7 days in the fridge. That’s right—barely a week. Store-bought pesto, on the other hand, is a little more resilient, holding out for 1 to 2 weeks after opening, assuming you didn’t buy it in 2018.
But wait—don’t slam the fridge door just yet. These are just rough guidelines. Your pesto’s lifespan depends on a few sneaky factors. And by “sneaky,” I mean “science.” And by “science,” I mean “how much air you let in.”
The Villain in the Room: Oxygen
Pesto’s worst enemy isn’t time. It’s air. That green color you love? It comes from basil, and basil is a diva that turns brown when exposed to oxygen. It’s like a sad avocado, but with more garlic attitude.
So, if you leave the jar half-empty and loose, your pesto will oxidize faster than a gossip magazine at a hair salon. Press plastic wrap directly onto the surface before putting the lid on. It’s like giving your pesto a little oxygen-proof blanket. Tuck it in.
