Can Pesto Go Bad?

Pesto is a sauce made from fresh basil, pine nuts, and olive oil. It is often used as a sauce for pasta as well as a dip or as a sandwich spread.

Since pesto sauce is made with fresh basil, along with other ingredients high in oil, its shelf life after opening is quite limited.

The good news is since pesto sauce has plenty of uses, so you’ll have no trouble using up your supply in a flash!

Still, this sauce is quite delicate so storing it properly is a critical part of extending its shelf life. This goes especially for homemade pesto that’s free of preservatives.

Fresh pesto
Fresh pesto

Can Pesto Go Bad?

As with any type of sauce made from fresh, oily ingredients, pesto will go bad at some point.

The storage life of pesto oil is limited because the olive oil and pine nuts are high in oils that could go rancid much faster than the other ingredients.

If you’re making pesto from scratch, make small batches of it rather than a massive batch that you cannot use up in a week or less. Or freeze most of it soon after making.

Thankfully, several storage techniques can extend the shelf life of the sauce past its date.

You see, the storage conditions of the sauce will affect its shelf life. By being mindful of how to store pesto, there is no reason why you couldn’t extend the storage life of this beloved sauce.

Making pesto using mortar and pestle
Making pesto using mortar and pestle

Signs that Pesto Has Gone Bad

For starters, take a look at the sauce. If its color has changed (e.g., it turned brown instead of the usual green), or there are any specs of mold on the surface, it’s gone. The same applies to any visible discolorations.

The second thing is the smell. If it smells rancid or like old oil, it’s rancid and you should discard it. Same thing if it smells funny.

Eating rancid pesto most likely won’t make you sick, but it won’t taste anywhere near fresh pesto.

If your pesto looks and smells okay, give it a taste. If it tastes weird in any way, chances are it has gone bad.

And even if it didn’t, what’s the point of eating off-putting pesto?

Pesto, spinach, and chicken
Pesto, spinach, and chicken

How to Store Pesto?

When it comes to an unopened store-bought pesto, you should store it the same way it was stored in the supermarket.

Sometimes it’s in the refrigerated section, while most of the time it’s where other sauces in jars and bottles are. Because of that, it’s easiest to do the same the supermarket did.

Once you open the container, the leftovers should sit in the fridge, and be sealed well. In most cases pesto comes in a jar, so that’s not a problem.

If your pesto was in the refrigerated section, it probably won’t keep for more than a week past its date. And only about 2 or 3 days after opening.

For pesto jars that weren’t chilled, they usually are pasteurized and last months. Because of that, adding an extra couple of weeks shouldn’t be a problem. But once you open the container, expect it to retain quality for no more than 4 to 5 days.

Pasta, pesto, and spinach
Pasta, pesto, and spinach

For homemade pesto, its place is in the fridge. And again, always keep the pesto tightly closed after every use to reduce oxidation and minimize air exposure.

Store homemade pesto in an airtight container.

The pesto you made should last for about two to three days. If you need more time, freezing might be the way to go.

Fresh basil
Fresh basil

Can You Freeze Pesto?

Yes, you can freeze pesto sauce to extend its shelf life. This goes especially for homemade pesto that’s free of preservatives as well as sauce that’s nearing its shelf life.

Simply spoon the sauce into an airtight container, leaving a few inches of space before closing the lid. Keep the airtight lid secure so the sauce won’t leak out. Write the storage date then stick in the freezer.

We highly recommend packing the product into manageable portions so you don’t have to defrost the entire container for a single serving of pesto sauce!

If you don’t have as many containers as you need, or use only a small amount of pesto at a time, you can freeze it in ice cube trays.

When kept in the freezer, store-bought pesto sauce will keep for 8 months or so. Homemade pesto should retain quality for at least 4 months.

Pasta with pesto and spinach
Pasta with pesto and spinach

Summary

  • Store unopened pesto the same way it was stored in the supermarket. Once you open the container, remember to keep it in the fridge and sealed well.
  • Homemade pesto belongs to the fridge.
  • If pesto smells like old oil, has any signs of mold or other discolorations, or tastes off, discard it.