I made the MBC for the first time yesterday and followed the recipe to the teeth. The sugar reached 250 degrees and was poured in a heat proof (pyrex) bowl. I think I took too long to scrape out the remaining sugar from the sauce pan because the sugar crystallized in the bowl. I made the mistake of not melting it again, but added it to the butter cream. Now I've got a yummy BC with lumps. What can I do to break the lumps? Any ideas? The BC is currently in the freezer.
A few pointers:
Stir your sugar while it slowly melts. When it comes to a boil, don't stir anymore.
Take a brush with water and brush down all of the sugar on the side of the pan above the sugar water line.
I only take mine to 245. Then I pour from the pan straight into the mixing bowl. All of that moving around may be causing some crystalization. I know some chefs suggest this but I have never seen the point.
Sometimes I still get crystals on the bottom of the pan, but just discard it. Don't scrape it or try to use it.
Do you have a link to a recipe for mousseline buttercream? Sounds interesting!
I forgot to add something:
Sometimes no matter what I do, I will get crystals. I am also a confectioner of historic candies and I cannot do the following trick. When all else fails, add a few drops of corn syrup. It retards the formation of crystals. In historic baking, lemon juice will also work, but if the original recipe did not call for it, I have to just stand over it and do all the above steps, including stirring until the sugar is melted. I recreate authentic recipes from famous people for museums all over the country. If they didn't specify some citric acid, I can't add it. But I think that it was done, just not written in the recipe as it was a given in historic cooking methods. Too bad for me. It's a pain.
If lemon, 1/4 to 1/2 tsp in a buttercream, will not affect the flavor, it is an option too.