How Long Does Pesto Last Once Opened

Last Tuesday, I opened a beautiful jar of green pesto, slathered it generously over my pasta, and then — just like that — put the lid back on and tossed it in the fridge. About nine days later, I grabbed it again, opened the cap, and was greeted by… a smell I won't describe in polite company.

That's when I thought, "Wait, how long does pesto actually last once opened?" Turns out, I probably took my sweet time with that jar. Let's dig into this so you don't end up in my shoes.

The Short Answer

If your pesto is store-bought and unopened, you're golden for a pretty long time — sometimes well past the printed date. But the moment you break that seal, the clock starts ticking. An opened jar of commercial pesto generally lasts about 5 to 7 days in the refrigerator.

Yeah, that's shorter than most of us would like to admit. And yes, I'm looking at myself right here.

What About Homemade Pesto?

Homemade pesto is a whole different story — and honestly? It's even more delicate. Because it lacks the preservatives and stabilizers you find in store-bought versions, homemade pesto usually holds up for about 3 to 5 days in the fridge.

Now, before you panic, there's a little trick I wish I'd known: adding a thin layer of olive oil on top of the pesto surface before storing it. It creates a sort of shield between the air and the ingredients, slowing down that unpleasant oxidation — which is exactly what turns your bright green pesto into a sad, brownish sludge.

How Long Does Pesto Last After Opening?

Why Does Pesto Turn Brown?

Great question. The basil in pesto is sensitive to oxygen. The moment the pesto meets air, the enzymes in the basil start reacting, and the color shifts from vibrant green to brownish. It's not dangerous, per se, but it does mean the flavor has degraded. And nobody wants bland pesto — that kind of defeats the entire purpose, doesn't it?

Pouring a little olive oil on top works like a tiny army blocking the oxygen from reaching the basil. Pool of oil. Barrier. Problem solved. Well… partially solved.

How to Tell If Pesto Has Gone Bad

So, if you've got a jar sitting in the back of your fridge — you know the one — here are some clues that it's time to say goodbye:

Smell: If the pesto smells sour, off, or just generally funky, it's done. Trust your nose; it rarely lies. Mold: Any visible fuzzy spots on the surface mean immediate disposal. Don't even think about scooping around it — just toss it. Texture: Slimy or watery separation is another red flag.

How Long Does Pesto Last After Opening?

If you're not sure — and I say this with love — just throw it out. It's not worth the gamble.

Can You Freeze Pesto?

Absolutely, and this might be your best move if you can't finish a jar quickly. Pesto freezes beautifully for up to 3 to 6 months if stored properly.

The easiest way? Pour it into an ice cube tray, freeze the cubes solid, then transfer them to a freezer bag. Want one serving? Just pop out a cube, toss it in a pan, and you're back in business. It's practical, it's smart, and it makes you feel eerily organized in the kitchen.

Fridge vs. Freezer: A Quick Comparison

Let's keep it simple. Opened store-bought pesto: 5-7 days in the fridge. Opened homemade pesto: 3-5 days in the fridge. Either version, frozen: 3-6 months in the freezer. See how freezing gives you a massive stretch of time?

How Long Pesto Is Good For Once It's Opened

And honestly? Being that person who remembers to freeze their leftovers makes you feel impossibly accomplished. You deserve that small win.

Final Thoughts

So, if you're anything like past-me and you open pesto with more enthusiasm than caution, just know the answer: opened pesto lasts roughly 3 to 7 days, depending on whether it's homemade or store-bought. Beyond that, you're gambling with flavor — and possibly your stomach.

Keep it fresh, layer that olive oil, or simply freeze it. Your future self will thank you, and your taste buds definitely will too.

Now go — check that jar in your fridge. You're welcome.