Here's where things get really interesting. If you're planning on using your buttercream for decorating, you'll want to make sure it's still fresh and pliable. Think of it like playdough - you want it to be easy to work with, not hard and crumbly. So, even if it's still technically "good" after 3 days, it might not be the best for decorating purposes.
Does Buttercream Thicken In Fridge at Bailey Walters blog
But, what if you want to freeze it? Well, that's a whole different story. Frozen buttercream can last for up to 3 months, which is pretty amazing. Just think of it like putting your favorite dessert on pause - you can come back to it whenever you're ready.
