I have only made buttercream a handful of times but I was wondering about freezing.
I tried searching the "Everything you want to know about buttercream" forum thread and didn't find many answers. I also posted in it, but I think I might get answers quicker in here.

How long can you freeze buttercream?
Can you keep just butter, no shortening buttercream at room temp?
What is the best way to store? Glass air-tight container? Ziplock bag?
Should I thaw at room temp or in fridge?
Does it have to be completely thawed before whipping?

This is my recipe that I have used:
4 cups (460 grams) confectioners sugar (icing or powdered sugar), sifted
1 cup (226 grams) unsalted butter, room temperature
1 teaspoon pure vanilla extract
4 tablespoons milk or light cream

Thanks so much!

How long can you freeze buttercream?
approx 3 months

Can you keep just butter, no shortening buttercream at room temp?
for short periods of time - it contains dairy products [besides butter]

What is the best way to store? Glass air-tight container? Ziplock bag?
As long as it is air-tight - either one

Should I thaw at room temp or in fridge?
Fridge

Does it have to be completely thawed before whipping?
yes

Thank you!

I make a shortening and/or butter based buttercream with powdered sugar, depending on the season.

I freeze it all of the time, generally in plastic containers. It usually get used up within 3 months, but I would have no problem with up to 6 months.

I usually defrost in the fridge & then on the counter. I don't re-whip, just stir with a spatula to re-mix.

I use heavy whipping cream, not milk, and because of the extra fat, it helps in preservation. The less water (and milk has more water than heavy cream) in the BC, the longer it can stand at room temp.

Rae

Thanks Rae!! Great tips. Wouldn't have thought about the cream!