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How to Tell if Buttermilk Is Bad

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Milk is a great source of calcium, vitamins, and other nutrients that are vital to our body. If you have children, then you will know how important it is to instill the habit of drinking milk when they’re still young.

There are many types of milk that we can consume such as regular dairy milk, almond milk, oat milk, non-dairy milk, and many more.

But there is one type of versatile milk that is not only good for drinking but can be used to enhance the flavor and texture of many foods such as cookies and cakes. It is called buttermilk.

Buttermilk is produced from the fermentation of dairy products. Like other milk, it won’t last forever and tends to go bad over time.

How can we tell if the buttermilk we bought has spoiled?

Similar to most dairy products, you can easily spot spoiled buttermilk by the way it smells and its texture. If it smells bad and there is mold in and around the package or container, then it is time to throw it away.

Pouring homemade buttermilk

Discoloration or any color change that is completely different from its original form is another obvious sign that your milk is spoiled.

There are also a few other signs that show how spoiled buttermilk often looks, tastes, and smells. That being said, let’s dive in deeper to know more.

What Does Buttermilk Smell Like When It Goes Bad?

Our nose is capable of detecting the slightest change in odor or smell. Hence, the quickest way to know whether your buttermilk has spoiled or not is to smell it.

Buttermilk has a tangy and butter-like smell that is not so different from the smell of most fresh dairy products. However, if the smell is unpleasantly stronger and sour, then it is time to throw the milk away.

Buttermilk made with yogurt

Fresh and good buttermilk won’t give off a pungent smell. And you can instantly notice how the strength of the smell gradually decreases when it is exposed to outside air. Over time, this smell can turn sour, especially when the milk has spoiled.

How Long Does Buttermilk Last in the Fridge?

Buttermilk should be kept in the fridge to extend its shelf life. The optimum temperature to store this milk would be below 40°F or 4.4°C. Anything above this temperature can promote bacterial growth, resulting in spoiled buttermilk.

On average, you can keep unopened buttermilk in the fridge indefinitely and for around 1 to 2 weeks after its expiration date.

Meanwhile, opened buttermilk can only last around 2 weeks in the fridge. After this period, it is wise for you to check for any signs of spoilage before drinking.

Since opened buttermilk is prone to outside exposure and changes in its temperature, you can’t expect it to last longer than unopened ones.

Portrait of young smiling woman drinking

Is Buttermilk Supposed to Taste Sour?

There are a good number of varieties of buttermilks that you can find. Back in the old days, buttermilk was produced from the by-product of churned butter.

During this process, heavy cream was strained and churned until it turned buttery, creating a residue of low-fat milk. Most of the buttermilk that is being sold today is a lot different than traditional buttermilk.

Modern-day buttermilk or cultured buttermilk is produced through a fermentation process of skim milk containing bacterial cultures called Lactococcus lactis ssp. lactis.

During this process, other ingredients such as citric acid and salt are also added. This process takes around 14 to 16 hours, before lactic acid and diacetyl are added, which contribute to the tangy and buttery taste of the milk. Hence, buttermilk is not supposed to taste sour.

This is also where it gets hard for most people to differentiate between good and spoiled buttermilk.

However, it is within your own common sense to recognize whether that tangy taste is the same as when you first bought the milk, or if it has become stronger and tastes unusually sour.

The tangy taste of good buttermilk won’t be as bad and pungent as the one that is spoiled.

Drawing conclusions based on the taste alone can be quite hard. Hence, you should check whether the milk texture has changed and become chunky.

a cup of Buttermilk

Is Buttermilk Supposed to Be Chunky?

Aside from smell and taste, you should also look for changes in the texture of the buttermilk. Fresh buttermilk will have a clear and smooth texture. Unless you’re using frozen buttermilk, there is no reason for good buttermilk to be chunky.

Any signs of chunkiness and changes in its viscosity are major signs that the milk is spoiled. If you pour the milk out of the carton and it goes out in thick lumps that look like butter, you can be sure that it has gone bad. 

In some cases, fresh buttermilk will have small lumps that can be shaken or stirred away easily. This is not a cause for concern. But if the lumps are bigger, harder, and come with discoloration or a sour smell, the milk is definitely spoiled.

Can You Use Expired Buttermilk?

Buttermilk has its own sell-by or best-by date. This is where you can refer to know when it will expire. In some cases, unopened buttermilk that has passed its expiration date can still be used for a week or two, given that its smell, taste, and texture hasn’t changed.

However, opened buttermilk in the fridge and the ones that are stored at room temperature have a higher chance to spoil quickly, even before their expiration date. So, the best way to keep buttermilk and make it last until its expiration date is to store it in the fridge.

As always, do a quick check before using it and throw the buttermilk away if it has spoiled, even if it’s still unopened.

buttermilk made from yogurt

Can You Freeze Buttermilk?

Another way to extend the shelf life of buttermilk is by keeping it in the freezer. But be sure that the freezer is clean and free from any contamination. You can either freeze it directly in its carton or pour it into an airtight container.

It is also better for you to spare enough space in the freezer or keep other frozen products away from the buttermilk.

No matter if it’s opened or unopened buttermilk, it can last around 2 to 3 months in the freezer. The only downside of freezing buttermilk is that you can only use it for baking or cooking.

This is because frozen buttermilk will become slightly chunky or lumpy even after you have defrosted it. Due to this change in its texture and consistency, it is not suitable for drinking and won’t taste as good as refrigerated buttermilk.

Final Thoughts

Every dairy product is labeled with its own expiration date. As a consumer, you should always be aware of the information written on the pack of your buttermilk and every other edible item to avoid using or buying buttermilk that has passed its expiration date.

Good hygiene is also important to ensure that the milk will last longer. Keep your fridge clean and regularly check the best-by date on the carton before drinking.