Does Buttermilk Smell Sour? Surprising Facts About This Dairy Product

Buttermilk is a dairy product that is made when cream is churned to form butter. It is often used in baking, and has a sour smell. Buttermilk can last for up to two weeks in the fridge, but it will spoil if it’s left out too long. In this blog post, we will discuss some surprising facts about buttermilk!

What is the difference between Milk and Buttermilk?

When fresh cow’s milk is drawn (before homogenization), it contains quite large fat globules. When unpaused, such milk sinks and the fat globules float to the top, forming a layer on the surface of the liquid. Cream is what results from this process.

Coffee grinds, on the other hand, can be removed from the milk and used as is for various applications – cooking, baking and flavoring among them. To do so, simply heat up the milk until it begins to steam.


To make butter, the cream must be “churned.” A lot of stirring. This causes the fat globules to stick together, eventually resulting in a semi-solid substance known as butter. Some liquid remains and can be removed. Buttermilk is the common name for this liquid.

Is Buttermilk supposed to smell a little bit Sour?

Yes, buttermilk is supposed to have a sour smell. This is because of the lactic acid that is formed as the milk sours. This souring happens when bacteria are added to the milk, either naturally or through industrial fermentation. The lactic acid bacteria convert lactose (milk sugar) into lactic acid and carbon dioxide gas.

Another reason for the buttermilk’s sour smell is its high level of acidic content. Buttermilk has a pH of about four, while regular cow’s milk has a pH of six to six and a half. This high level of acidity is what helps to preserve buttermilk.

However, if the buttermilk smells excessively sour or off, it may be spoiled and not safe to drink. If this is the case, discard it and do not consume it. Spoiled buttermilk can cause nausea and vomiting.

How long can Buttermilk ast in the fridge?

Buttermilk will last for about two weeks in the fridge. If it is left out at room temperature, it will only last for a day or two. Once it is opened, you should keep buttermilk in the fridge and use it within a week.

The Signs That Buttermilk Is Bad

However, buttermilk will sometimes come out of condition because its protein content varies from time to time. There are a few signs to look for if buttermilk is off or not, so if you’re not sure whether it’s on or off, check for additional signals to help you decide.

Here are some signs to look for if the buttermilk has gone bad using the various senses.

  • Smell
  • Look
  • Texture


Buttermilk does have a distinct tang to it, but the smell tends to grow more sour as it spoils. When the buttermilk is first produced, it has a neutral or weakly acidic taste. After a few days to a week, depending on storage conditions, though, it becomes considerably more sour. You will be able to detect it right away if this happens. Note that buttermilk will have a stronger odor when it’s packed in a closed carton since the aroma hasn’t had a chance to leave.


You can tell if buttermilk has gone off simply by looking at it. Buttermilk may develop a slight color when spoilt. Buttermilk with a long shelf life, like that found in many refrigerators and dairy products, has an expiration date. Mold can begin to grow on the surface of buttermilk that is past its expiry date. This is due to an increased bacterial count, and if mold is detected in or on the buttermilk, it should be thrown away immediately because it isn’t worth risking foodborne illnesses from drinking bacteria-infected buttermilk.


Buttermilk should have a thicker texture than regular milk. If it’s too runny, your butter and cream will separate, producing buttermilk curds (also known as “butterstones”) that look like little white rocks floating in the liquid.

Buttermilk that has gone bad becomes clumpy and thick. It will be difficult to pour and there will be sizable clumps. There’s no way to repair buttermilk that’s become lumpy, as it’s likely to be rancid.

In Conclusions

Buttermilk is a dairy product that has some surprising properties. It can last in the fridge for up to two weeks, but it will spoil if left out too long. In this blog post, we have discussed some of the most interesting facts about buttermilk. We hope you enjoyed reading it! Share this blog post with your friends and family to spread the word about this delicious dairy product.