I have read posts where people use hot water instead of cold water when making butter cream. If my butter cream recipe uses butter and shortening will this cause any issues with the frosting or will it be ok. Since we can't get Hi ratio shortening in Ca anymore I am having problems with air bubbles in my frosting. They usually disappear with a printed paper towel method but I would like to be able to have a smooth frosting by just using a hot knife. TIA.

1. I use boiling water in my bc recipe.
2. Why can't you get Hi Ratio shortening in CA? Hi Ratio is NOT just the transfat stuff.

After I make my french buttercream with the boiling sugar water, and after the butter is added, I finish with a teaspoon or two of hot tap water to bring out the smoothness.