Does butter go bad?

In this short article, we will answer the question “Does butter go bad?” and will explain why butter can go rancid.

Does butter go bad?

Yes, terrible butter does exist. You should start with the production process to comprehend why. Cream, which is produced after the sterilisation process of pasteurisation, is the basic ingredient in butter. 

The water that was left inside the butter is eliminated by beating and kneading this cream, which is high in fat. As a result, 82% of the product is made primarily of milk fat as opposed to 16% of water. 

Flavourings and salt (or not) make up the remaining 2%. Butter does go rancid and needs cautious storage because it is still essentially milk.

Should I keep butter in or out of the refrigerator?

You should keep it inside the refrigerator. When butter is left out of the refrigerator, bacteria and fungi gorge on it, turning it rancid and bitter. If the butter is left out and does not return, it may even produce food poisoning. 

Temperatures between 0 and 5 °C inside the refrigerator stop its multiplication, extending the food’s shelf life. But remain calm. That doesn’t mean that enjoying soft butter on toast is no longer enjoyable. Simply don’t misuse it. 

Up to two hours can pass when the butter is left outside. However, the trick is to leave the butter on the refrigerator door, where the lower temperature makes it less hard if you don’t want to get up at 6 am to store the butter until 8 am.

There may be a serious health danger if you eat butter that hasn’t been refrigerated. Let’s first take a look at some of the chemical components of butter to better understand why this happens. 

Why does butter deteriorate if it is not refrigerated?

To respond to this query, we must first identify the components that emerge from the creation of butter:

A glycerol molecule, which is a molecule of glycerin try alcohol, and three fatty acids (long-chain carboxylic acids, typically with 4 to 22 carbon atoms in even number, with only one carboxyl group each) combine to form a compound known as a glyceride. 

Since butter is fat, it belongs to this group of lipids (propanetriol). “Triglycerides are another name for glycerides because of this. Solid fats are produced if the fatty acid radicals that generated the molecule have no double bonds, or if they are saturated like oils (liquids).

Both vegetables and animals are capable of developing fats in this way. Since butter is made from cow’s milk, it is considered to be of animal origin.

The main step in making butter is getting a milk cream, a dairy product rich in fat, as an emulsion in water with the aid of a creamer. This cream is standardised to have a fat content between 38 and 42% before being pasteurised at 85 °C to kill bacteria. 

The dough is next washed and kneaded to make it more homogeneous and to control its consistency and structure. This is done in a continuous mixer to separate the buttermilk from the fat. It’s possible to add salt and artificial colours. 

Linoleic acid, which has a melting point of -5 C and is an omega-6 fatty acid, makes up the majority of the fat in butter. Butter tends to harden at lower temperatures due to its near-linear structure and high content of saturated fats. 

There are two unsaturations in linoleic acid. When a substance is made entirely of saturated fatty acids, it has a very high melting point and is no longer suitable for the consistency needed for this kind of product. 

Butter has predominantly saturated chains and a little number of unsaturated acids, making it semi-solid. 

This composition makes it so that if we leave the butter out of the refrigerator, contact with air humidity, oxygen, and high temperatures will lead to the multiplication of microorganisms, which will generate a very complex sort of reaction known as rancidity. 

When butter is stored poorly, that is, outside of a refrigerator, free radicals are created by the double bonds of unsaturated fatty acids. These free radicals then react with oxygen (an oxidation reaction) to create products that change the properties of lipids. 

These glycerides will then experience chain breakdown, resulting in the formation of rancid-smelling acids. Butyric acid (H3C (CH2)2 COOH) is the primary acid responsible for this odour. 

Its name is even derived from the Latin word butyral, which means “butter,” because it imparts the rancidity of butter with a unique odour. 

This oxidative ratification is aided by elements present in the environment outside of the refrigerator, such as more oxygen, exposure to sunlight, and an increase in temperature that accelerates oxidation.

For example, an increase in temperature of 10ºC will result in a two-fold increase in the reaction of oxygen with fat. The presence of metals that act as catalysts and water (moisture) both speed up the reaction. 

Another type of rancidity, known as hydrolytic rancidity, is made more likely even by the presence of water. 

In this type of rancidity, the ester link is broken by an enzyme like lipase or a chemical agent in the presence of moisture, releasing saturated and free unsaturated fatty acids in the process.


In this short article, we answered the question “Does butter go bad?” and explained why butter can go rancid.


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