An unusual thing occurred this last weekend when a single blueberry muffin lasted in a container on my counter for about 3-4 days. And by "lasted," I mean it was not eaten that day or the next day, which is what almost always happens.
I believe I made the muffins on Friday morning. So come Monday morning, I was looking for something to have for breakfast. I was thinking about making another batch of muffins, but I figured I might as well eat up that last muffin first. It looked okay (though I probably should have taken it as a bad sign that there were a few fruit flies hanging around it), so I took a bite.
It is difficult to describe to you how NASTY spoiled food tastes, other than to say it was the second most disgusting thing I have ever tasted in my life. The first most disgusting came from a very similar situation, where I tried a bite of gluten-free cornbread that had been sitting out on my parents' counter (though covered) for about 4-5 days. Cornbread lasts at least about that long, right? Haha... WRONG. Not gluten-free cornbread, anyway. I felt bad for practically spewing it back out and immediately rinsing out my mouth right in front of my mom (who had just told me the bread should be fine), but folks... it was NASTY!!!! Rancid would be a better word. Given another 24 hours, that muffin probably would have equaled if not surpassed the cornbread in nastiness.
So the moral of this story is: if you will eat your homemade gluten-free goods within about 24 hours, you're fine. Maybe 36... I'm pretty sure I've eaten some things the following night after I made something one morning. But any longer than that, PLEASE do yourself a favor and refrigerate it!!! I hear it should last about 4-5 days in the fridge. I kept a coffee cake in the fridge for a week, and it was okay (though a bit dry), but since muffins are a bit more moist, I wouldn't advise keeping them that long.
Just eat your muffins up, kids.