All About Sweet onion
Your complete guide to sweet onion - discover how to store it properly, identify when it's gone bad, and find the best substitutes for your recipes.
How Long Does Sweet onion Last?
Storage times and freshness tips for sweet onion 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.
Whole, Uncut (Room Temperature/Pantry)1-3 weeks
Signs of Spoilage
Soft spots, moisture, dark patches, mold growth, sprouting green shoots, strong pungent or sour odor.
How to Check
Visual inspection: Look for any discoloration, mold (fuzzy green/black spots), or sprouts. Touch test: Gently squeeze the onion; it should be firm. If it feels soft, mushy, or slimy, it's likely spoiled. Smell test: A strong, unpleasant, or sour odor, distinct from its mild onion scent, indicates spoilage.
Storage Tips
Store in a cool, dry, dark, well-ventilated area. Avoid storing in plastic bags, as this traps moisture and accelerates spoilage. Do not store near potatoes, as both release gases that can hasten spoilage in the other.
Cut, Raw (Refrigerator)3-5 days
Signs of Spoilage
Slimy texture, strong pungent or sour odor, discoloration (yellowing, browning, or dullness), visible mold.
How to Check
Visual inspection: Look for a slimy film on the surface, browning or yellowing edges, or any fuzzy mold. Touch test: The onion should feel crisp; if it's slimy or overly soft, it's past its prime. Smell test: A very strong, sour, or unpleasant smell beyond its typical fresh pungency is a clear sign of spoilage.
Storage Tips
Store in an airtight container or tightly wrapped in plastic wrap to minimize odor transfer to other foods and prevent dehydration. Place in the coldest part of the refrigerator.
Cooked (Refrigerator)3-4 days
Signs of Spoilage
Off-odor (sour, fermented, or moldy), slimy or mushy texture, visible mold, unusual discoloration.
How to Check
Visual inspection: Look for any mold growth, unusual color changes, or a slimy appearance. Smell test: A sour, fermented, or 'off' smell is the primary indicator. Touch test: The texture should not be slimy or excessively mushy, beyond what is expected from cooking.
Storage Tips
Cool cooked onions quickly after preparation and store in an airtight container. Reheat thoroughly to 165°F (74°C) before serving.
Frozen (Whole or Cut)6-8 months (for best quality); safe indefinitely
Signs of Spoilage
Significant freezer burn (dry, discolored patches), strong off-odor (rare if properly stored), significant texture degradation upon thawing.
How to Check
Visual inspection: Look for excessive ice crystals or dry, leathery spots (freezer burn). Smell test: While frozen items don't typically 'spoil' in the microbial sense, a stale or 'freezer' smell can indicate quality degradation. Texture upon thawing: Will be softer and mushier than fresh, but should not be slimy or completely disintegrated.
Storage Tips
Peel and chop/slice onions as desired before freezing. For best quality, blanching for 1-2 minutes can help retain color and texture, but it's not strictly necessary. Store in freezer-safe bags or containers, removing as much air as possible to prevent freezer burn. Frozen onions are best used in cooked dishes where their softened texture won't be an issue.