Does Butter Go Bad?


Butter is one of those products that you always have and never need, until you need it and don’t have it.

So does butter go bad? Yes it certainly does. The question isn’t necessarily whether or not butter does go bad, because let’s be honest, we have all at one time or another accidentally tasted rancid butter. The question should rather be why does it go bad and what can you do to prevent it.

In today’s jam-packed article, we will be looking at what butter is, why it goes bad, the shelf life of it and what you can do to prevent it going rancid.

can butter go bad

What is the Shelf Life of Butter?

Butter gets made in massive batches on a daily bases therefore the best way to know what the shelf life of your block is, is to check the expiry date on the packaging.

But more often than not, that expiry date means nothing and your butter is rancid before you have used half the block; frustrating isn’t it?

Be it salted or unsalted butter, it should keep for at least 3 months if kept only in the refrigerator. This is subject to the expiry date, i.e. how old the butter was when you bought it.

Salted butter tends to have a longer shelf life than unsalted butter. This is because salt is a preservative, thus the salt in the salted butter, you guessed it, preserves it.

Lucky for us, because using a whole block of butter takes a bit of time, it doesn’t go off quicker once you have opened it like milk or cream would.

Here is where the shelf life of butter shortens considerably; as soon as you leave butter outside of the refrigerator, the shelf life decreases immediately.

How long does butter last: Consume within 1-2 months after opening your butter.

Why Does Butter Go Bad?

why does butter go bad

Butter goes bad for one reason only, when kept at room temperature.

If you constantly keep butter at room temperature, the oils in the butter will go bad. This is because butter is made from animal products (the milk) which contains a lot of fat.

Although the high-fat content is one of the reasons butter has a much longer shelf life compared to milk, the fat is also the element that spoils and causes the rancid-taste.

Oxidation (leaving butter somewhere without being covered) and light accelerated spoilage.

How To Tell if your Butter is Spoiled

The first and most obvious way to tell if your butter has gone off is by looking at the expiry date and how you stored it.

If it is past the expiry date, the butter has most likely gone bad or become too risky to still use. However, you can look at other signs (which we will mention below) to check if it truly has gone off.

The second most obvious thing to look at is how the butter has been stored. If you kept the butter in the refrigerator for the whole time, it might still be fine a couple of weeks past the expiry date.

If the butter was frozen, it will still be fine a few months after the expiry date.

butter with knife

However, if you kept the butter outside the fridge for the majority of the time, the expiry date will not be met and your butter is most likely off by then, if not much sooner.

Other things you can check to determine if the butter has gone rancid include;

  • discoloration
  • off-taste
  • off-smell

When the butter is anything other than yellow, for example when it starts forming darker or lighter spots, your butter isn’t safe to use anymore.

Other forms of discoloration include the growth of actual mold or even mold spores. These spores are usually black but can also be blue or green. If your butter has any form of mold on it, discard immediately.

If your butter smells sour or rancid (or anything else than butter), you should check the expiry date or even taste a tiny piece. Rather be safe than sorry and discard the butter.

The same goes for when you taste the butter; if there is any rancid or sour taste, your butter has gone off and shouldn’t be used.

The risk of becoming seriously ill from consuming rancid butter is very low, your body will still experience some discomfort, mainly stomach aches.

How To Properly Store Butter

butter storage

As previously mentioned, the spoilage of butter is accelerated by oxidation and light.

The best way to store butter is to;

  • Wrap it is baking or non-stick wax paper. This will prevent direct contact with oxygen and also prevent the butter from absorbing other smells.

You do not have to wrap it in plastic or saran wrap or store it in an airtight container. Using these methods might cause the butter to sweat and form water droplets on the surface.  Simply wrapping it in wax paper is enough to keep it for the amount of time you need it.

  • Keep it away from direct light or a heat source. This can be best achieved by storing it in the refrigerator at 41 degrees Fahrenheit (5 degrees Celcius).

Butter can also be frozen in an airtight container for a couple of months, although this will affect the quality and mostly the texture of it once defrosted.

The problem you face now is that you need softened butter but cannot leave it outside otherwise it will go rancid much faster.

The solution? Only leave out the amount of butter you need in a butter dish – enough for a couple of days. This way you always have a small amount of soft butter which can constantly be refilled and the rest of the butter stays cold in the refrigerator.

Simple, yet very effective.


As you can now see, storing butter or keeping it from going off isn’t difficult in any way. Simple keep it in the refrigerator to prevent oxidation.

Only keep out a small amount at room temperature for you to easily use when needed.

By knowing what makes it go off, you can easily prevent and overcome the problems and keep your butter fresher for longer.

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