I use dried pasteurized egg white powder for Swiss Meringue Buttercream because it's less expensive than fresh eggs and avoids the problem of how to use the egg yolks.
Would there be a difference in the buttercream using heated meringue, as one does when using fresh egg whites, versus room-temperature meringue, as one could do with dried egg white powder?
I've been whisking reconstituted dried egg whites over simmering water until the sugar dissolves and the meringue is hot; whisking the meringue until it's completely cooled (about 10 minutes); then adding the softened butter and flavorings. I use a ratio of 1 part egg whites to 1-1/2 to 2 parts sugar (lesser amount of sugar for vanilla) to 2 parts butter to make a buttercream that's not too rich for my family to enjoy.
Is meringue made with heated egg whites structurally different from meringue from room temperature egg whites?