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Is It Safe to Not Refrigerate Butter | The Debate Settled

In the process of making candy for the holidays, I somehow managed to leave a whole package of butter out of the refrigerator overnight and was wondering whether it can safely be used or if I should just toss it. I’ve heard people argue both ways, so I did a little research and was surprised by the findings.

It is safe to store butter outside the fridge at room temperature for up to 10 days. The fats in butter protect it from bacterial growth but will slowly decompose and become rancid. A good rule of thumb is if you will not use the entire stick within 2 days, it’s better to keep it in the fridge.

Butter’s survival outside of the refrigerator will depend on a few factors, especially butter type and temperature. The rest of the article will cover the storage guidelines of butter and answer a few common questions.

Butter Storage Safety

Butter is a product made from milk or cream and is the result of a churning process that separates milk or cream into buttermilk and butterfat. Buttermilk is liquid, and butterfat is predominantly solid.

This means that butter is over 80% fat, with the rest being made up of water. This combination makes it unlike most dairy products because it is extremely low in carbohydrates and proteins. However, its high fat content makes it more resistant to the growth of bacteria.

Many people prefer to leave their butter out on the counter to keep it softer and more pliable, which is perfectly safe under certain circumstances. To maximize shelf life, cover butter to protect it from particles in the air.

I wrote an article on the storage guidelines for butter, be sure to check it out.

How Long Can I Leave Butter Out at Room Temperature?

Because of butter’s high fat content, it can safely sit on the counter for up to 10 days. In this time period, the product is not likely to spoil or become rancid, assuming your house is not too warm. If your home sits at a temperature above 77 ° F (25 ° C), you should store your butter in the fridge to keep it fresher longer.

Warm temperatures will speed up the oxidation process and increase the chance of bacteria spreading. Oxidation results in your butter spoiling faster.

Spoiled butter will develop a weird “off” taste. If this happens, it should just be tossed out. While rancid butter probably won’t cause you to become seriously ill, it can certainly give you a stomach ache. Of course, you probably won’t be able to eat that much since it will taste terrible.

Pro Tip: A good compromise is to keep a small amount of butter on the counter for easy use and keep the rest stored in the refrigerator, especially if you will not be using the whole tub or square of butter right away.

Does Salted vs. Unsalted Matter?

How long your butter can safely stay outside the refrigerator depends on whether it is salted or unsalted. The United States Food and Drug Administration (FDA) found that many types of bacteria can survive on unsalted butter. As a result, unsalted and unpasteurized butter should be stored in the refrigerator. Refrigeration lowers the bacterial growth risk.

In contrast, salted butter can safely be stored both in the fridge or at room temperature. Salted butter can be stored outside of the refrigerator because it has a low risk of bacterial growth and has a shelf life of a few months when stored at room temperature. The recommended room temperature for butter storage is between 70-77 ° Fahrenheit (21-25 ° Celsius).

Can You Leave Butter Out Overnight to Soften?

Salted or unsalted butter can safely be left out overnight. The best practice is not to take out the whole container to soften unless you plan to use it up within a couple of days. Just take out what you need and leave the rest in the refrigerator. This will keep it fresher longer.

Also, keep in mind that butter softens really quickly at room temperature. I just did an experiment where I left it out for only an hour, and it was soft enough to spread easily. You could also microwave it for a few seconds to soften it quickly.

Does Margarine Need to Be Refrigerated?

Soft margarine needs to be refrigerated to keep it fresh, while hard margarine can be left out on the counter for up to 10 days, just like butter.

When margarine is left out on the counter, it can separate into water and oils. The change of margarine to oil and water can affect the overall taste of the spread and make it difficult to use. This happens more often with the soft tub type of margarine because of its polyunsaturated or monounsaturated fats. It is recommended that you immediately return soft tub margarine to the refrigerator after use.

Stick margarine differs in its overall composition. This type of margarine contains considerable levels of saturated and trans fats. These fats help protect the overall shape and taste of the product when at room temperature. If well covered, stick margarine may be able to survive for up to 10 days at room temperature before going rancid.


I was certainly surprised to find that some folks say it is alright to keep butter unrefrigerated for up to a week or even longer. My personal philosophy is always to keep butter and margarine refrigerated unless I’m softening a stick or two to use later in the day.

According to the AskUSDA website, butter is safe at room temperature, but it is always safer to leave out only the amount you can use within a day or two. As for me, I think I’ll follow the advice of the experts at the USDA.