Pesto is a traditional Italian blend of fresh basil, garlic, nuts and cheese. It makes a flavorful addition to sandwiches, soups, pastas and many other foods. Fresh pesto has a very short shelf life, though, even when you keep it in the refrigerator. You can extend the shelf life of this delicate condiment up to three or four months by putting it in the freezer. Just make sure you package it correctly to prevent freezer burn and keep your pesto tasting fresh.
You can freeze a whole batch of pesto by placing it in glass freezer jars or plastic containers rated for temperatures below 0 degrees Fahrenheit. Avoid conventional containers not made for the freezer since they can crack or split. The National Center for Home Food Preservation recommends freezing pesto with 1/2 inch of head space to allow for expansion. Adding an extra 1/4 inch of olive oil can help seal the pesto and keep it fresh longer. You can get a similar effect with less oil by applying plastic wrap directly to the surface of the pesto before freezing, then sealing the container as usual.
Pesto for One Meal
Many cooks only need a few tablespoons of pesto at a time. This can make it difficult to deal with a large frozen container. The solution is to freeze your pesto in smaller batches. Silicone baking cups work very well, as do conventional muffin pans lined with parchment paper. Simply fill the cups and place them in the freezer until the pesto has solidified. Remove the frozen pesto and wrap it in plastic to keep out excess oxygen. Place the frozen portions in a lidded container or resealable bag and put them back into the freezer.
If you prefer to use your pesto in single serving dishes like sandwiches, soup toppings or individual portions of pasta, freezing it in ice cube trays makes things easy. You can use any type of tray, but silicone styles make removing the frozen pesto easier. Once the pesto has solidified, remove each cube, wrap it individually in plastic, and store it in a covered container for optimal freshness. You can also freeze single dollops of pesto by spooning it on a piece of plastic wrap, freezing it, then wrapping and storing just like a pesto cube.
You'll get the best flavor and longest storage life if you freeze your pesto immediately after making it. If you can't do this, make sure that you get your pesto into the freezer within five to seven days. Commercially prepared pesto stays fresh in the refrigerator for a little longer, but it's still best to freeze it within two weeks of opening.