A simple solution would be to keep my covered butter dish out on the counter or in a cupboard, where the butter stays room temperature and perfectly spreadable at all times. But for some reason I just haven’t been able to do it, which makes me wonder: Does butter really need to be refrigerated?
Buttering bread with cold butter is pure misery — but does butter need to be refrigerated? If not, how long does butter last and how long can butter sit out before it goes bad?
Ultimately, we can’t tell you exactly how long you can leave butter out. We have no problem with leaving butter out to soften as long as it is well-covered. It usually doesn’t take us more than a couple days to go through a stick anyway! We’ve never had rancid butter in that time.
A Chowhound finds out that two friends keep butter out on the kitchen counter, not in the refrigerator. So SIMIHOUND posed the question to fellow ‘hounds: Is this a common practice? And how long does room-temp butter last before it goes rancid? If there’s one thing I know to be true, it’s that butter makes everything better.
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.
But for the butter to be safe for that long, it should be salted, pasteurized butter. It also won't work during the summer. If your kitchen is above 70 degrees, you should keep your butter in the fridge, no matter what kind it is. And if the butter goes rancid, then it's time to throw it out. How can you tell if butter is bad? Smell it.
Butter can be kept unrefrigerated for several days, but conservative estimates put the shelf life of room temperature butter at one to two days, at most. The ambient temperature of the room will determine how quickly the butter spoils; keeping it at 65 degrees Fahrenheit or below is best.
Once she knew keeping butter out was both something other people did and could do safely, Mertzel went on to invent her own butter dish—the Butterie, which, thanks to its flip-top lid and no-skid bottom, prevents a lot of the greasy messes that traditional dishes can result in. Good butter and clean counters are something we can always get behind.
Butter usually can be kept out for several days without going rancid (salted butter will keep longer because salt acts as a preservative). Exactly how long butter will stay fresh at room temperature depends on how much heat and light it gets and whether it’s wrapped.
They recommend leaving butter out for only a day or two. There's been a buzz lately about this question. Extra Crispy addressed it in this article: "There are some caveats, ... How long can I leave butter at room temperature?