Tradition is frequently pitted against food safety in the debate over butter storage. Some are concerned about spoiling, while others would rather leave it out for easy spreading.
Although butter is less likely to develop bacteria due to its high fat and low water content, it can still turn rancid or develop mold if left out for an extended period of time, particularly in warm, humid kitchens.
Butter stays fresher and safer when refrigerated, but spreading becomes more difficult.
Experts advise storing a small portion in a covered dish at room temperature for a few days and then chilling the remainder. Counter butter can also be kept safe by using a crock or butter bell.