Does Buttermilk Go Bad? | Cook's Illustrated (2024)

I always keep buttermilk in the fridge, since I like to make pancakes and soda bread on a whim. More often than not, the buttermilk is well past its expiration date since the stuff always looks and smells perfectly fine for weeks. (Plus, we know those dates aren’t officially regulated and aren’t meant to convey anything about food safety.) I often joke with my family that buttermilk never goes bad.

Of course, it does eventually. There are obvious signs of spoilage like blue-green mold growth or when the buttermilk’s naturally sour aroma gets more pungent and its viscous body becomes gloppy. But does it start to spoil before those cues are obvious?

In the test kitchen, we asked industry experts to weigh in on buttermilk shelf life and compared their input with our own experience.—Elizabeth Bomze

What Is Buttermilk?

The term applies to a range of dairy products, but most commercial buttermilk is skim milk that manufacturers culture by adding lactic acid bacteria. The bacteria give the milk its thickness and distinctive sour aroma and acidity.

How Long Does Buttermilk Last?

Buttermilk has a much longer shelf life than fresh milk because its abundance of lactic acid is hostile to the growth of harmful bacteria. But based on what we’ve learned from industry experts and our test kitchen experience, it doesn’t have a precise shelf life.

  • The dairy farm that produces the buttermilk we use in the test kitchen told us to consume their product within five to seven days after opening.

  • Guidelines from agricultural programs at various universities recommend consuming buttermilk within three weeks of the date stamped on the package.

  • In the test kitchen, we’ve found that buttermilk won’t turn truly bad (signified by mold growth) until at least three weeks after opening.

Can You Freeze Buttermilk?

Absolutely. It freezes really well. Here’s an easy way to do it if you think you won’t finish the carton in time.

  • Pour buttermilk into an ice cube tray and freeze until solid.

  • Transfer buttermilk cubes to a zipper-lock bag and freeze until ready to use.

Alternatively, there are so many good ways to use up buttermilk.

Does Buttermilk Go Bad? | Cook's Illustrated (2024)

FAQs

Does Buttermilk Go Bad? | Cook's Illustrated? ›

Guidelines from agricultural programs at various universities recommend consuming buttermilk within three weeks of the date stamped on the package. In the test kitchen, we've found that buttermilk won't turn truly bad (signified by mold growth) until at least three weeks after opening.

How can you tell if buttermilk has gone bad? ›

Signs of Spoiled or Bad Buttermilk

Pour some into a cup and look at its consistency. It should be smooth, but if it's really thick and has clumps or chunks, the buttermilk has gone bad. The buttermilk smells strong and sour.

Can I bake with expired buttermilk? ›

As long as your aged buttermilk smells like it did when it was fresh and looks creamy, it's usable. Its tang and buttery notes are most likely diminished, but you can cook and bake with it. It has a low pH or level of acidity, which inhibits the growth of bad-for-you bacteria.

Why does my buttermilk look like yogurt? ›

Today's buttermilk has live cultures in it to help it ferment- similar to yogurt. You can see the little lumps on the spoon- this is good buttermilk.

What is buttermilk supposed to look like? ›

Buttermilk is a little thicker than regular milk and it has natural little lumps in it. So, yes, buttermilk is supposed to be a little chunky, just like me. If it's supposed to be chunky and it smells a little sour, how can you tell if buttermilk is bad? If it's super thick and smells super sour, that's not good.

Does dry buttermilk go bad? ›

Most fresh dairy products will spoil if left alone for too long; however, there are shelf stable versions that last much longer than their refrigerated counterparts. These non-perishables include powdered milk, evaporated milk, powdered egg substitute, egg white substitute and powdered buttermilk.

How long can buttermilk last in the fridge? ›

While an expiration date can help provide some insight as to when it will spoil, it often doesn't take into consideration whether the buttermilk was opened. Since quality fades quicker after opening, buttermilk will last a maximum of 2 weeks in the fridge.

What can I do with old buttermilk? ›

Whisk It into a Dip, Sauce, or Dressing

another cake. For an easy savory option, drizzle some buttermilk into your next salad dressing or creamy dip. You can whip up a simple, herby ranch dressing or any easy buttermilk dressing. Drizzle some into bean dips or caramelized onion dips.

Can I use 2 month expired buttermilk? ›

Buttermilk itself has a shelf life of 14 days you should consume before expiry date. But if there is no nasty smell and fungus in your buttermilk you can consume it. But if you see your buttermilk starts separating you should discard it.

Can buttermilk look curdled? ›

Sometimes overculturing (too long or too warm) can cause the buttermilk to curdle or become lumpy before it separates fully. To make a smooth consistency, simply whisk it. (Remove some of the whey if you like, or stir it back in.)

Does buttermilk have good bacteria like yogurt? ›

The fermentation process involved in making buttermilk produces beneficial bacteria that are similar to those found in yogurt. These probiotics can help promote digestive health by improving the balance of gut bacteria and aiding in the absorption of nutrients.

What are the yellow dots in buttermilk? ›

Lactic acid in the milk produced a bacteria that fermented milk. Cultured buttermilk is from milk that has been pasteurized and hom*ogenized. Then one of two types of bacteria is added, which encourages the natural fermentation process. Some manufacturers add tiny yellow flakes to imitate butter.

Is buttermilk supposed to be thick or thin? ›

Before you walk out of the store, check the buy by date or the use by date. No it should not be chunky, buttermilk is supposed to be the consistency of thick cream or thin yogurt, not chunky.

How long is buttermilk good for once opened? ›

You may know that fermented foods can last a long time, and lactic acid does inhibit the growth of bacteria, but unlike pickles or miso, buttermilk doesn't last for months. An opened container will only stay fresh for two weeks when stored in a refrigerator, and for up to three months if kept in the freezer.

Should homemade buttermilk be lumpy? ›

Don't worry if the mixture looks curdled or has small white lumps in it, it will be fine once cooked.

When should you throw out buttermilk? ›

How to Tell If Buttermilk Has Gone Bad. Once your buttermilk is chunky, and you can't pour it, or if it has visible mold, it's time to throw it out. Another sign is a strong sour odor.

What to do with old buttermilk? ›

Whisk It into a Dip, Sauce, or Dressing

another cake. For an easy savory option, drizzle some buttermilk into your next salad dressing or creamy dip. You can whip up a simple, herby ranch dressing or any easy buttermilk dressing. Drizzle some into bean dips or caramelized onion dips.

What color is buttermilk? ›

Buttermilk color is a light, bright pastel yellow and part of our Yellows Collection. Inspired by the baker's go-to ingredients for biscuits, buttermilk adds a bit of warmth and tang.

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