How to Preserve Pesto

Pesto adds a fresh, herbal note to pasta or gnocchi.

Pesto is one of the signature sauces of the Italian canon. It originates in the coastal region of Liguria, and more specifically in the great trading port of Genoa. The local basil is remarkably fragrant and strongly flavored, and the Genoese take great pride in this home grown specialty. The traditional ingredients of pesto, basil, garlic, olive oil, pine nuts and Parmesan cheese are all readily available in America today, so anyone can make fresh pesto. Although it is best if eaten when it is freshly made, pesto may also be stored for later use.

Things You'll Need

• Canning jars, or other sealable jars
• Olive oil
• Plastic film wrap
• Freezer bags
• Ice cube trays (optional)

Instructions

1. Pack the fresh-made pesto into small jars for storage, ideally with no more than one or two portions per jar. Smooth the top of the pesto with the back of a spoon, and drizzle a small amount of olive oil over the top to provide a seal. Screw the lids onto the jars, and store in a cool, dark place for up to two months.

2. Pack the pesto into jars, as directed above, and press a small piece of plastic film wrap to the surface of the pesto. Store in the refrigerator no longer than two or three days, for the best flavor and color.

3. Freeze single or meal-sized portions of pesto in zipper-seal freezer bags, for easy use. Press out any air before sealing the bag, for maximum freshness. Bags of frozen pesto may be thawed overnight in the refrigerator for next-day use, or in less than an hour under cold running water.

4. Freeze pesto in ice cubes trays, if desired, as an alternative. Once the sauce is frozen, empty the ice cube tray into a zipper-seal freezer bag. For longer term storage, each cube of pesto may be individually wrapped before going into the freezer bag.

Tips & Warnings

• Blanching the basil in boiling water before making the pesto will help the color stay fresh and green.

• A small portion of spinach leaves may be blanched, and added to the pesto. This will not materially change the flavor, and will provide a more vivid green color.

• Storing pesto at room temperature under a seal of oil is the traditional way of preserving it for later use. This technique involves a risk of botulism poisoning, which may be minimized by blanching the basil leaves in boiling water before they are used in the sauce. Refrigeration and freezing remain safer methods.

References

• "On Food and Cooking: The Science and Lore of the Kitchen, Revised Second Edition"; Harold S. McGee, 1984
• National Center for Home Food Preservation: Freezing Pesto
• National Center for Home Food Preservation: Canning FAQ
• The Nibble: The Best Pesto Sauce