How to Tell if Butter is Bad

Butter is a must in everyone’s kitchen. It’s the ideal topping for toast and potatoes and a critical ingredient for treats like cake and cookies. Unfortunately, though, butter doesn’t last forever. How can you tell if it’s gone bad?

Although butter has a pretty impressive shelf life, it does go bad. The first sign of spoilage is a rotten smell. From there, the butter can develop changes in texture, discoloration, and, lastly, mold. If you notice any of these signs, you need to toss your butter ASAP.

Hey, welcome to this article! My name’s Michelle, and I’m a big butter fanatic. This is unsurprising, considering I’ve been a home baker for the past ten years. Butter is just part of my livelihood. That said, I’ve dealt with my fair share of spoiled butter. I’m here to share the signs of rancid butter.

Keep reading to find out how to tell if butter is bad.

How to Tell if Butter is Bad (5 Signs)

The good news is that eating old butter won’t make you sick (although you might get a tummy ache from the response of eating something that tastes sour and gross). 

However, just because you won’t get ill doesn’t mean you should consume it. After all, who wants to eat something spoiled?

That said, here are the top five signs that your butter has gone bad.

1. Rancid Smell

If you smell a stick or tub of butter, it will smell neutral with a somewhat pleasantly sweet flavor. (Honestly, I love the smell of butter!)

But if you give your butter a whiff and it has an odd or disgusting smell, it means that it’s gone bad.

A rotten smell is the first sign that your butter has gone bad. So, if you notice anything but a neutral or pleasing odor, toss your butter ASAP and buy or make your own – it’s easier than you might think!

2. Change in Texture

Most people store their butter in the fridge, as butter isn’t supposed to sit on the countertop for longer than a day or two, according to the USDA.

Storing in the fridge, your butter will take on a rock-hard consistency – which is why you need to let it sit at room temperature or zap it in the microwave before using it in your favorite recipes.

If you pull your butter out of the fridge and it’s not hard – but mushy – you have a problem. A change in texture means that the butter is going bad.

3. Discoloration

To be frank, it doesn’t matter what you’re looking at. Whether it’s a cake, a piece of pizza, or a stick of butter, if you see discoloration on your food item, it’s a clear indicator that it’s gone bad. 

With that in mind, take a close look at your butter. Do you see any colorful spots that aren’t supposed to be there? Then get rid of it, even if it’s only a tiny amount of discoloration.

4. Mold


The word alone is enough to make my stomach turn. How about yours?

If you see fuzzy friends sitting on your mold, it’s time to toss it. 

5. Weird Taste

If you don’t see any other signs of spoilage, your final test is the famous taste test.

Like its smell, butter should have a relatively neutral yet sweet and slightly rich flavor. Use a spoon to scoop a small portion of butter and give it a taste. If it has a sour or odd flavor, it’s gone bad.

How Long Does Butter Last?

When it comes to butter shelf life, this can get confusing. After all, the USDA claims that butter shouldn’t be left at room temp for longer than a day or two. Yet, your grandma likely has a butter dish filled with a butter stick that’s been sitting on her countertop for weeks.

What gives?!

Let’s take a closer look at how long butter actually lasts.

1. Countertop (One Day to Two Weeks)

When it comes to storing butter on the counter, some people say it’s a definite no-no, while others swear by their handy dandy room temp butter sticks.

The fact of the matter is unsalted and whipped varieties should not sit on the counter for longer than a day or two.

Yet, salted butter can sit at room temperature for up to two weeks. The added salt halts bacterial growth, even in slightly warmer temperatures.

However, keep in mind that salted butter must be stored correctly to last the two-week mark. For instance, it must be placed in an airtight container away from heat or light. It should not sit in kitchens higher than 72F. 

2. Refrigerator (Up to Three Months)

If you prefer unsalted or whipped butter, or the thought of leaving your butter on the countertop makes you nervous, don’t worry – you can successfully store it in the refrigerator.

All types of butter will last up to three months in the fridge when stored correctly in an airtight container. 

In fact, plenty of people claim that refrigerated butter lasts up to six months in the fridge. However, quality begins to deteriorate past the three-month mark, so it’s best to use it quickly.

3. Freezer (Up to a Year)

For those needing long-term butter storage, the freezer is the best choice.

In the freezer, butter can easily last up to a year. While you can use it beyond this point, it won’t have the same quality as it did during its first year in the freezer.

Again, ensure the butter is sealed in an airtight container or resealable freezer bag to prolong its longevity. 


Who knew butter could go bad and have so many signs of spoilage? At least now, you don’t have to worry about using rancid butter in your recipes! Oh, but before you leave, I implore you to check out these frequently asked questions.

What happens if you eat bad butter?

The (great?) thing about eating rancid butter is that you won’t get sick. The most that can happen is a stomach ache and possibly vomiting, depending on how disgusted you are by the odd flavor that rancid butter produces.

Is it OK to eat expired butter?

If your butter doesn’t show any signs of spoilage and has been properly stored, then it’s likely a-okay to consume. Remember that most products have a “best-by” date, which is not the same as an expiration date.

What does bad butter smell like?

Bad butter omits a rotten smell. However, it might not be as evident as, say, spoiled milk. Look for an odd smell that butter doesn’t usually emit. Most people say it has a somewhat sour scent that is undesirable

Butter Can Go Bad and Has Many Signs of Spoilage

Butter has a remarkable shelf life, but it can go bad. The most significant indicators of rancid butter include an awful smell, change in texture (mushiness), discoloration, and moldy spots. The final test is a taste test, and bad butter will have a sour and yucky flavor. If you notice any of these signs, get rid of the butter ASAP.

How do you tell that your butter has gone bad?

About Michelle
I have been a lover of sweets since day one. This led me on a self-taught baking journey starting at the age of 13. It's been over 10 years since the start of my baking adventures, and I’ve learned a lot along the way. Now, people rave about my delectable treats, whether it’s a chocolate cake or a strawberry crepe.

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  • Michelle L. Sontheimer

    My husband and I buy 3-4 lbs of butter at Costco. He likes to freeze it in the original packaging.
    It has a horrible taste no matter how long it’s been there. Does it matter what packaging you use?

    Michelle Sontheimer

    • Michelle

      Hi Michelle,
      Sorry to hear about that. I do the same thing and don’t struggle with odd flavors. Could it be something in your freezer causing the bad taste? Maybe something to look into.