Butter comes from churned pasteurized milk. Pasteurizing milk involves heating the liquid to a degree that reduces harmful bacteria. Churning takes place to complete the process. Sweet cream butter has added salt that helps with preservation. Unsalted butter, sometimes called sweet butter, does not contain extra salt. According to the USDA, commercial butter consists of at least 80 percent milk fat and 20 percent water and salt.
Bacteria, food-borne illnesses and rancidity are the main concerns with storing butter on the counter. Rancidity occurs because of exposure to air, heat and bacteria. Storing your butter in the refrigerator increases the shelf life. According to the University of Missouri Extension, there are no real health concerns with keeping butter on the counter, provided you store it in an airtight container.
The National Dairy Council recommends storing butter in the sealed manufacturer’s container and in the refrigerator to increase shelf life. Salted butter lasts two months in the refrigerator, while unsalted lasts only two weeks. You can safely freeze butter for up to nine months if it contains salt and five months if it's unsalted. The USDA recommends storing butter in the freezer for up to two months when you do not intend to use it within a few days of purchase. Baking 911 suggests keeping butter on the counter in a tightly covered butter dish for several days at a room temperature of 65 degrees Fahrenheit. To make the butter last for a longer period of time on your counter top, store it in a butter crock. This insulated stoneware receptacle keeps the butter cool by packing the butter in the hollowed-out lid and filling the jar with cold water. Replace the water once a week and you can safely store your butter on the counter for up to 30 days.
Butter absorbs the odors from other foods rather easily. When this happens, the taste of butter is affected. To help prevent this from occurring, store butter in the original packaging or a tightly sealed butter dish. If you store butter in the refrigerator, keep it in a separate drawer to protect it from soaking up any odors. Soften refrigerated butter by placing it at room temperature for 15 minutes prior to use; return it to the refrigerator after use.