Despite what I’ll tactfully call conflicting opinions in my household, it turns out that yes, butter is almost always safe to eat after being left out on the counter.
Not only is room-temperature butter better for spreading and creaming sugar while baking, it turns out that you can leave properly stored butter out for a surprisingly long time.
“Butter is safe to eat after being out at room temperature,” Bri Bell, a registered dietitian, and food safety expert, told Allrecipes.
“One reason it doesn’t go bad as quickly as other dairy products at room temperature is because it’s low in carbohydrates and proteins, which are mould and bacteria’s preferred food sources.“
But does safe mean tasty? Is there an upper limit to how long you can leave butter out on the side? And if so, what is it?
It’ll be safe for ages ― but delicious for as little as a couple of hours
Part of it has to do with storage. On one, more extreme end, bog butter ― butter buried under a bog to preserve it for longer ― has been found to last for literally hundreds of years without posing a health threat to anyone who eats it.
But unless you’ve got an airtight, subterranean cubby-hole of your own, your best bet is probably a butter dish or something similarly airtight that won’t absorb smells from your cooking. This should keep it safe to eat for ages, provided your kitchen isn’t too hot.
However, the question of safety is different to the question of flavour. While butter might be safe to eat after a couple of days on your countertops, its taste might be impacted by leaving the fridge.
Tonja Engen, Culinary Content Specialist for butter experts Land O’Lakes, told Allrecipes “Do not leave butter at room temperature for more than 4 hours. Always return any unused butter to the refrigerator and be aware that butter left outside refrigeration may become darker in colour and have the flavour affected.”
If you need to soften butter for baking or spreading, she says that “you can cut the butter into small chunks and let stand at room temperature for about 15 minutes.”
Or grate frozen butter for a quick-fix for baking, she adds.
The United States Department of Agriculture’s recommendations say that “Butter and margarine are safe at room temperature. However, if butter is left out at room temperature for several days, the flavour can turn rancid so it’s best to leave out whatever you can use within a day or two.”
In other words, while your butter is safe out on the counters for a remarkably long time, its creamy flavour might degrade in a matter of hours.
Honestly, this is the most clear-cut case of “ignorance is bliss” I’ve ever seen...