How Long Can Unsalted Butter Go Unrefrigerated?

Pat of fresh farm butter on a dish


A world without butter is hard to imagine. In the middle of spreading, sauteing, browning or melting it, you might lose sight of some basic butter storage tips. Many recipes call for room temperature, unsalted butter but don't state how to thaw it, and many pieces of toast have been ruined by a stiff, unyielding pad of butter. Follow the safety and storage rules so you don't get the short end of the stick.

Not Too Long

Butter should be taken out of the refrigerator 10 to 15 minutes before using, advises the U.S. Department of Agriculture. But it takes longer than 15 minutes to bring butter to room temperature, which many recipes call for. Many professional bakers bring butter to room temperature overnight. Covering unrefrigerated butter or leaving it in the wax paper reduces the likelihood it will become rancid, absorbing flavors or odors. The chance of bacterial blooms that lead to foodborne illness is relatively low, because butter is made from pasteurized milk.

Soften It Up

If you need room temperature butter for baking but you don't want to leave it sitting out of the refrigerator, slice the necessary amount into tablespoon-sized pats and place them on a plate. Microwave for five to 10 seconds to soften, so that pressing the pats with your finger produces an indentation. Instead of spreading softened butter on toast, melt a small amount of cold butter in the microwave and spread it on the soft bread before toasting.

Keep It Cool

A French butter keeper is another way to have softened, spreadable butter on hand, while adhering to the refrigeration guidelines. It is a lidded pot of butter immersed in cold water. You can buy French butter keepers at kitchen supply stores. You could conceivably make your own butter keeper by placing a dab of butter in a small bowl that fits inside a larger container with a lid, such as a single-serve crock dish.

Other Tips

Because butter easily absorbs flavors and odors, refrigerate it in its original wrapping and rewrap it tightly after using. The USDA recommends freezing butter if you don't use it after three days, while "Cook's Illustrated" reports that butter stored in the back of the refrigerator, where the temperature is coldest, can last more than two weeks. Sources vary on how long frozen butter lasts, from two months according to the USDA to four months according to "Cook's Illustrated."