The need to refrigerate butter depends on the type of butter you have. There are two main types of butter:
Unsalted Butter: Unsalted butter is made purely from cream and does not contain any added salt. This type of butter can become rancid more quickly if left at room temperature, especially in warm environments. To extend its shelf life, it is recommended to refrigerate unsalted butter.
Salted Butter: Salted butter, as the name suggests, contains added salt, which acts as a preservative. Due to the salt content, salted butter is less susceptible to spoilage, and it can be left at room temperature for a short period without going bad. Many people keep salted butter on the kitchen counter for easy spreading. However, if you live in a very hot climate or if you won't use the butter for an extended period, refrigerating it can still be a good idea to maintain its freshness.
In summary, salted butter can be left at room temperature for a short time without immediate concern, but unrefrigerated unsalted butter may go bad faster. To prolong the shelf life of either type, refrigeration is a safer option, and it will not significantly affect the taste or quality of the butter. Additionally, if you prefer your butter spreadable, you can take it out of the fridge a little while before using it to soften it up.