So, you’ve mastered chopping, know how long it takes to boil pasta, and learned how to whip up amazing recipes at the drop of a hat. Still, there are a few things you might be doing wrong in the kitchen that don’t actually know are wrong to begin with. One of those has to do with butter—and the question of, does it need to be refrigerated or not?
Some people swear by leaving the stuff out on the counter, while others balk at the idea of ever keeping a dairy product outside the refrigerator for longer than ten minutes. Plus, the official USDA guideline states that butter should be refrigerated and only softened “ten to fifteen minutes” before use.
However, according John Bruhn, a dairy-foods specialist at the University of California at Davis, that’s not the complete story. “Most butter contains added salt, which impedes the growth of spoilage bacteria,” he told us. So, while butter will go bad, it happens much more slowly than with unfermented dairy products, such as milk.
Today’s salted butter will rarely spoil, even if you leave it unrefrigerated all the time. Unsalted butter takes about a week to go bad, but it contains enough natural salt to slow the growth of bacteria.
The real issue to consider is rancidity, which is when butter develops an off taste and smell. That rate can be reduced by always covering unrefrigerated butter—you don’t want it to have contact with air. One good way it can be preserved at room temperature is by using a French butter keeper, which is a pot that keeps your butter immersed in cold water—and keeps it both soft and cold.
So, there you have it. No need to sound the alarm bells if you forget to put your butter away after dinner. At the same time, if you are looking to preserve the creamy stuff for a particularly long length of time, you should probably stick it in the fridge.