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Can Pesto Go Bad?

Pesto is a sauce made from fresh basil, pine nuts, and olive oil. It is often used as a pasta sauce as well as a dip or 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 pesto sauce has plenty of uses. Therefore, you shouldn’t have any trouble using up your supply quickly!

Nevertheless, pesto 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 goes bad at some point.

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

Fortunately, by taking good care of pesto, you can extend the shelf life of the sauce past its date. More on that later.

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 like old oil (or rancid0, it’s rancid and you should discard it. The same thing holds true if it smells funny.

Eating rancid pesto most likely won’t make you sick, but it won’t taste nearly as good as 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 and How Long It Lasts?

Store unopened store-bought pesto, 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 simply 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 you cannot reseal the package, transfer the sauce into an airtight container.

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, don’t expect the dip to retain quality for more than 4 to 5 days.

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

For homemade pesto, its place is in the fridge in an airtight container.

Keep pesto tightly closed after every use to reduce oxidation and minimize air exposure. This will help retain its quality for longer.

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, neede for fresh pesto

Can You Freeze Pesto?

Yes, you can freeze pesto to extend its shelf life, and it works well for both homemade and store-bought pesto. All you need is a plastic container and a minute or two.

To freeze pesto, spoon the sauce into an airtight container, leaving a few inches of space before closing the lid.

Keep the airtight lid secure so that the sauce won’t leak out. And add a label with the name and storage date if you like, then stick it in the freezer.

Pack the sauce into manageable portions so you don’t have to defrost the entire container for a single serving of pesto. If you don’t have as many containers as you need, or use only a small amount of pesto at a time, freeze it in ice cube trays.

When kept in the freezer, store-bought pesto sauce will retain the best quality for about 8 months or so. The homemade variety usually doesn’t keep as well, so it’s best to finish it within like 6 months.

If you want to learn more about the topic, I wrote a whole guide on freezing pesto on my sister site CanYouFreezeThis.com.

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, keep it in the fridge and seal it well.
  • Homemade pesto should always be refrigerated.
  • If pesto smells like old oil, has any signs of mold or other discolorations, or tastes off, discard it.