All About Buttermilk
Your complete guide to buttermilk - discover how to store it properly, identify when it's gone bad, and find the best substitutes for your recipes.
How Long Does Buttermilk Last?
Storage times and freshness tips for buttermilk 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 refrigerator1-2 weeks past 'best by' or 'sell by' date
Signs of Spoilage
Unusual sour smell (beyond its typical tang), visible mold (green, pink, or black spots), significant thickening or curdling that doesn't dissipate with stirring, yellowish or discolored appearance.
How to Check
-
Visual Inspection: Check for any signs of mold on the surface or around the rim. Look for unusual discoloration or extreme separation that looks like chunky cottage cheese.
-
Smell Test: Open the container and take a good whiff. While buttermilk is naturally tangy, a spoiled batch will have a distinctly sour, pungent, yeasty, or 'off' odor.
-
Texture Check: If it looks and smells fine, pour a small amount. It should be relatively smooth, though some slight separation is normal. If it's excessively lumpy or slimy, it's likely bad.
Storage Tips
Store buttermilk in the coldest part of your refrigerator, typically the back, to maintain its temperature consistency. Keep the container tightly sealed to prevent absorption of other food odors and bacterial contamination.
Opened in refrigerator7-14 days after opening
Signs of Spoilage
Strongly acidic or 'off' odor, visible mold (any color), extreme separation into a very thick, lumpy solid and watery liquid, slimy texture, or a bitter taste.
How to Check
-
Smell Test: This is the most reliable indicator. A strong, unpleasant sourness, a yeasty smell, or a rotten odor indicates spoilage.
-
Visual Inspection: Look for any mold growth on the surface or sides of the container. Note any unusual color changes (e.g., yellowish tint) or excessive chunkiness that doesn't mix back in.
-
Texture Check: Pour a small amount. If it's noticeably slimy or has large, unappetizing curds, it's best to discard it.
-
Taste Test (Caution): If smell and visual checks are clear, a very small taste can confirm. Discard if it tastes overly bitter, excessively sour, or otherwise 'off'.
Storage Tips
Always reseal the container tightly after each use. Consider transferring to an airtight container if the original carton doesn't seal well. Avoid leaving buttermilk at room temperature for more than 2 hours, as this significantly accelerates spoilage. Use clean utensils when pouring to prevent cross-contamination.
Frozen3-6 months
Signs of Spoilage
While frozen, it won't spoil in the traditional sense. After thawing, look for signs of spoilage similar to refrigerated buttermilk: mold, extreme off-odors, or a very undesirable texture that makes it unusable even for cooking.
How to Check
-
Before Freezing: Ensure the buttermilk is fresh and free of spoilage signs.
-
After Thawing: The texture will likely be more separated and slightly grainy, which is normal for frozen dairy. Stir it vigorously. Then, perform a Smell Test and Visual Inspection for mold or truly 'off' odors. If it smells or looks bad, discard.
Storage Tips
Buttermilk freezes well for cooking and baking, but its texture often becomes grainy or separated upon thawing, making it less ideal for drinking straight. For best results, freeze buttermilk in smaller, pre-measured portions (e.g., in ice cube trays, then transfer to a freezer bag, or in 1-cup containers) for easy thawing. Thaw buttermilk slowly in the refrigerator overnight. Stir or whisk well after thawing to reincorpor solids and liquid.