I made "The Well Dressed Cake Swiss Meringue Buttercream" tonight and it came out great. I decided to make another double batch because I need quite a bit of icing. I used 10 egg whites instead of 5 and 2 cups of sugar instead of 1. I heated it in a bowl over simmering water until it was 160 degrees and then put it in my kitchen aid and began to beat it...except nothing happening. It wont stiffen at all. I'm in shock! I let it whip for 5-10 minutes and it looks exactly like it did when it was on the stove, very liquid and slightly frothy. Is it a lost cause?

Did you give your tools a vinegar and or alcohol bath?
Sounds like you got some grease or maybe a speck of yolk in their some where.

Since the last thing you made in the bowl contained a lot of fat, there were pretty obviously traces of that fat left behind inthe bowl or on the whisk. It's not a matter of washing it untilit looks clean, it's getting allt he fat off.

Vinegar and a salt scrub work wonders to defat a dry bowl and beaters after they've been washed.