All About Pesto
Your complete guide to pesto - discover how to store it properly, identify when it's gone bad, and find the best substitutes for your recipes.
How Long Does Pesto Last?
Storage times and freshness tips for pesto in different conditions.
Safety first: This guide provides general information. When in doubt, throw it out! Trust your senses and err on the side of caution. If something smells, looks, or tastes off, don't consume it.
Unopened Pesto (Shelf-Stable Jar)Refer to 'Best By' or 'Expiration' date (typically 6-12 months from production)
Signs of Spoilage
Bulging lid, leaking, mold growth visible through the jar, unusual discoloration (e.g., dark brown/black throughout), off-odor upon opening.
How to Check
Visually inspect the jar for any damage or signs of pressure (bulging lid). Check for visible mold or extreme color changes. Upon opening, smell for any sour, rancid, or fermented odors.
Storage Tips
Store in a cool, dark place away from direct sunlight. Once opened, it must be refrigerated.
Opened Pesto (Refrigerated)5-7 days for best quality, up to 1-2 weeks with proper handling
Signs of Spoilage
Darkening of the top layer (beyond normal oxidation), visible mold (white, green, black fuzzy spots), sour or rancid smell, fizzy texture, extreme separation with a watery layer at the bottom and a hard top.
How to Check
Visually inspect the surface for mold. Use a clean spoon to gently push aside any surface oil and check the pesto underneath. Smell the pesto for any off, sour, or overly pungent odors that are not characteristic of fresh basil and garlic. If it smells like old cheese or has a yeasty/fermented smell, it's likely spoiled. Do not taste if spoilage signs are present.
Storage Tips
To extend freshness, press a piece of plastic wrap directly onto the surface of the pesto to minimize air exposure, or pour a thin layer of olive oil over the surface before sealing the container. Always use clean utensils to avoid introducing bacteria.
Homemade Pesto (Refrigerated)3-5 days
Signs of Spoilage
Rapid darkening of the top layer, visible mold (often starts as white or light green fuzz), strong sour or rancid smell, slimy or unusually soft texture.
How to Check
Similar to opened store-bought pesto: visually check for mold and severe discoloration. Perform a smell test for sour, rancid, or fermented odors. Since homemade pesto is more perishable, be more cautious with any signs of spoilage.
Storage Tips
Homemade pesto oxidizes faster. Cover the surface with a thin layer of olive oil and/or plastic wrap pressed directly onto the surface to prevent air exposure. Store in an airtight container. Freezing is an excellent option for longer storage.
Pesto (Frozen)6-9 months for best quality, up to 12 months
Signs of Spoilage
Significant freezer burn (dry, discolored patches, excessive ice crystals), off-odor after thawing, a dull or muted flavor profile.
How to Check
Visually inspect for severe freezer burn. After thawing, smell the pesto – it should retain a fresh, herbaceous aroma. If it smells stale, bland, or rancid, it may have lost quality. The color might be a bit darker than fresh, but it shouldn't be brown or grey.
Storage Tips
Freeze pesto in small, individual portions (e.g., ice cube trays, small freezer-safe containers) for easy thawing and use. Cover the surface with a thin layer of olive oil before freezing to help preserve color and flavor. Thaw in the refrigerator overnight or on the counter for a few hours. Once thawed, use within 3-5 days and do not refreeze.