All About Unsalted butter
Your complete guide to unsalted butter - discover how to store it properly, identify when it's gone bad, and find the best substitutes for your recipes.
How Long Does Unsalted butter Last?
Storage times and freshness tips for unsalted butter 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 in Refrigerator1-3 months (often good past 'best by' date)
Signs of Spoilage
Sharp, sour, or 'cheesy' rancid smell; visible mold (green, black, or white fuzzy spots); significant discoloration (darker yellow, white streaks, or gray patches).
How to Check
Smell Test: Take a sniff – fresh butter has a mild, creamy aroma. Rancid butter will smell distinctly off, like old cheese, sour milk, or metallic. Visual Inspection: Look for any mold growth or abnormal color changes. Texture Test: If it appears overly dry or crumbly, it might be past its prime.
Storage Tips
Store in the coldest part of the refrigerator. Ensure packaging remains sealed to prevent odor absorption from other foods.
Opened in Refrigerator2-3 weeks
Signs of Spoilage
Rancid, sour, or metallic smell; visible mold; darkening of the butter's surface, especially where exposed to air; development of a 'cheesy' or 'off' flavor.
How to Check
Smell Test: Sniff for any sour, sharp, or unpleasant odors. Visual Inspection: Check for mold, dark yellowing, or white streaks on the exposed surface. Taste Test (Cautious): If smell and appearance are borderline, cut off a tiny piece from the center and taste it. If it tastes sour, bitter, or 'off,' discard immediately. Spit it out if it tastes bad.
Storage Tips
Store in an airtight butter dish or tightly rewrap in plastic wrap, foil, or an airtight container. This prevents odor absorption and oxidation, which causes rancidity. Cut off and discard any discolored or moldy portions if the rest of the butter appears and smells fine, but err on the side of caution.
At Room Temperature (Butter Dish)1-2 days (maximum 3 days in a cool environment)
Signs of Spoilage
Strong rancid smell; very soft, oily, or greasy texture; significant darkening of the surface; visible mold (less common in this short timeframe but possible).
How to Check
Smell Test: Rancid butter at room temperature will have a very noticeable sour or 'old oil' smell. Visual Inspection: Look for a very dark yellow or even brownish surface, or an overly oily sheen. Texture Test: If it's excessively soft, greasy, or has separated, it's likely spoiled.
Storage Tips
Unsalted butter is more perishable than salted butter at room temperature due to the lack of salt as a preservative. Only keep out small amounts you plan to use quickly. Use a lidded butter dish to protect it from air, light, and contaminants. Discard if your kitchen is particularly warm or if it's been out longer than 2 days. For slightly extended room temp storage, consider a butter bell (crock) which uses water to create an airtight seal, but still limit time.
Freezer6-9 months (quality may start to decline after 6 months, up to 1 year)
Signs of Spoilage
While frozen, signs are hard to detect. After thawing: distinct rancid smell, faded or uneven color, dry and crumbly texture (due to freezer burn), or 'off' flavor.
How to Check
Visual Inspection (before thawing): Check for signs of freezer burn (dry, discolored patches on the surface). Smell Test (after thawing): Once thawed, smell for rancidity. Taste Test (after thawing): If thawed and smell/look are okay, a small taste test can confirm quality.
Storage Tips
Wrap butter tightly in its original packaging, then add an additional layer of heavy-duty foil or place it in a freezer-safe bag or airtight container. This prevents freezer burn and absorption of freezer odors. Thaw butter slowly in the refrigerator for best texture. Do not refreeze thawed butter.