...did it need more moisture? Should I have beaten longer? beaten shorter?
In my experince those are from air bubbles that form and then pop while you are icing it.
Unless I have a mixer full of icing I only mix it on a low speed and for a short period of time after I have added in the powder sugar. I find the smaller amounts of icing I do (like a batch using only 1lb of sugar) the more air I get it in
I know there are others, even Indy has said, that beat the heck out of the icing, but I look at it like the idea behind SugarShacks icing. If you don't have a mixer full of icing, it is easy to incorporate added air into it, and while that is good for some things, it causes air bubbles and later marks in icing with some buttercreams.
I'd be curious to see how much icing those that make Indy's recipe and beat the heck out of it make at one time. Is your mixer full to the top, almost full or barely full?
I have a 4.5 quart Kitchenaid and when I mix up a batch using 2lbs of xxxsugar, the icing probably fills the bowl about 3/4 full. The beater is not completely covered and I'm sure I am beating in too much air. I know the Sugarshack approach is to have the bowl so full the beater is completely submerged in the frosting, but I've been too chicken to try mixing that much at a time. And I haven't adjusted the recipe amounts to create 1/4 to 1/3 more frosting than the original...Guess I'll have to bury my fears and dive into the super full bowl approach to see if that makes a difference. 
I know what you mean about the fear of over loading the bowl. Until you get past that, I would just suggest after you add the powder sugar that you mix it on a low speed and until it is mixed really well. The higher speeds and longer times are what does it.
You can also let the icing sit after you mix it, and take a flat spatula and press down on the icing, pushing it agains the side of the bowl to break up any airbubbles that may be in there.
I have come to the conclusion that these "air" things people keep talking about is caused by the dream whip because I made a batch and forgot the dream whip until the very last minute. The icing looked like crisco in the bowl until I added the dream whip, then I could see that it lookd a little "rough". However, as I've always said, once I put it on the cake and melvira'd it, it looks fine. If it became a trade off between "rough" looking (in the bowl) and the taste dream whip adds ..... I'll take the dream whip version anytime! 
Using a 20-qt mixer, I can't say I've ever covered the beater when making icing so maybe that method is dependent on the recipe. I've always had it in my head that using a whip will "whip" in air, but using a beater just "mashes" (or "beats") the ingredients (like mashing potatoes - no one ever accused me of whipping in air when I mash my potatoes with the beater 
). No idea how accurate that may or may not be ..... it's just the mindset I grew up with.
Indy, when you used your 20q bowl was it always usually pretty full though? Even if it wasn't above the beater?
I know in the smaller mixers when I make a smaller batch of icing it tends to get more air in it than when I do bigger batches.
Indy, when you used your 20q bowl was it always usually pretty full though? Even if it wasn't above the beater?
I know in the smaller mixers when I make a smaller batch of icing it tends to get more air in it than when I do bigger batches.
Not really. I'd say most of the time, it was only about 1/2 full. Sometimes more, but not all the time.
Hmmm. Maybe this is one of those, what works in one kitchen doesn't always work in another?
I made a batch of yours last night, and I did mix it on high like I've read and I have tons of bubbles in it.
Quote by @%username% on %date%
%body%