how long can butter be left at room temperature?

The only time my grandparents butter was NOT at room temperature was when it was in the oven, or skillet or the cow! Other than those times, it was on the kitchen table right next to the flour bin. I don't ever remember it going bad, rancid, or turning funky colors either.

If you google your question, you will find all sorts of answers, but most will agree that butter can last at room temperature up to 2 weeks. Grandma didn't have the option anyway, no electricity, no fridge! They did get "online" about 1968 or so, but I still never saw the butter go into the refrigerator.

Until it starts not tasting good or grows mold. Mine's been out of the fridge now for a couple of weeks. It's fine. Then again, it depends what you mean by room temperature. My house is fairly cool in winter, lows 60s. In summer, if it was 80F indoors, the butter would probably start tasting a bit off in less than week, maybe only a few days. That doesn't mean it's unsafe to eat, but it won't taste great.

With modern day refrigeration, folks are 'taught' to refrigerate butter. But older folks use a Butter Bell, to keep butter at room temperature on the counter top. It is a common practice, but really not necessary. Butter will retain its shape at room temperature, and make it easier to spread. Generally, it is good for around two weeks if kept covered.

You can leave butter out at room temperature for no more than 2 days. After that it will get a rancid taste.

The "technical" answer would be no more than 2 hours.

but I often leave butter out for a day or more.

If I plan on baking I may take butter out the night before and leave it out until I get ready to bake.

I do have a "butter keeper" that is supposed to let you keep butter out all the time but this summer I did have a stick of butter "turn" on me. tasted more like Parmesan cheese than butter.

So use common sense, if it tastes alright then it is fine, if it begins to "sour" toss it out.

If you live in a very warm area and do not keep the room temperatures cool then it will turn faster. If you keep your house a bit on the cool side it may last longer.

Indefinitely. Growing up my aunt left butter in a butter dish on her counter. I read many articles that you could leave butter unrefrigerated, so I started leaving a stick on my counter, some times for 3 weeks or longer, and it has never gone bad.

I never leave butter at room temperature, it goes rancid almost immediately.

Depending on your local country room temperature.

Until it's all used up.

One cube doesn't last too long in my house but I've never had a problem even when I've gone on vacation and left it sitting on the counter where it normally lives.

If it's your butter and your room, as long as you want.