I have made in the past buttercream half crisco, half butter without problems (other than it is not smooth because of air bubbles), but last night I made a big batch of chocolate buttercream for a wedding cake and decided to use powder milk instead of water, and corn syrop. I heard that it helps to smooth the icing. However, once on the cake the icing was sweating, it looked greasy. On the other hand, it was easier to smooth out. I have to ice another cake tonight and still have a lot of icing left over. I don´t want to get rid of it because that is a lot of materials..., but I don´t know what to do. Can I fix it? Any ideas of the problem? Could it be the powder milk or the corn syrop? If I make another batch without those ingredients and mix it together, could it help? Sorry for all the questions. I don´t know what to do Any help will be greatly appreciated!

I don't know how much help I will be here but I made a batch of BC half butter half crisco and mine looked the same way. I used water I think. It was really humid that day though so I wonder if that had anything to do with it.

I tried another batch last night without the corn syrop and it was much better. It wasn't completely matte, but it didn't shine as the other one. And I was able to smooth it out pretty well, not perfect but the best I have ever been able to do it. I think the powder milk somehow helps with this... However, it wasn't crusting much. My husband also thought that the humidity might have something to do with it. It was somewhat humid, but I wouldn't say it was super humid!

I wonder if the chocolate is making it shiny looking?

Could it be the new trans fat free Crisco? How long ago did you make this without problems? There is a 0 trans fat Crisco BC recipe here. You might take a look at it.

The same thing happened to me when I made my four tier cake with the blue flowers. I used the wilton recipe. The cake was so shiny and sweating. I used water too. But now I use Gourmetcakes crusting buttercream recipe from this site. I love it!!

Well, I am not sure that the chocolate is the problem, I have made chocolate buttercream before without problems, but maybe the new Crisco has something to do with it. Thanks for the tip, I will try gourmetcakes' recipe. I do think that corn syrop and Crisco don't go well together. I believe that combination was the big factor on the shiny result. I wish I could have access to the hi-ratio shortening everyone talks about. I haven't been able to find it in my city. One day... Thank you everyone for your feedback!

I have embraced the belief in the past year when Crisco went to ZTF that you MUST use a milk-based liquid when making bc. Water just doesn't cut it.

Personally I've decided that sugarshack's use of warmed coffee creamer is the best liquid to use.

I use the powdered coffee creamer, and mix it in equal measurements with hot water. Mixes smoothly with the bc .

Does using a milk-based liquid change the shelf life of the icing? Would it need to be refrigerated? I have also had buttercream sweating issues, but have been too paranoid of using milk in buttercream that isn't refrigerated
Thanks!

The coffee creamer is "non-dairy" and is shelf-stable. No need to refridgerate. There are many, many posts here on CC discussing how the small amount of milk used in bc doesn't compromise the shelf-stability of the final product. Even when I used 2% milk in my bc, I never refridgerated, and it was fine.