I made a batch of MMF. I mix 1/2 and 1/2 with homemade gumpast. I have been using to model figurines out of. I noticed yesterday when I was using it that there were these litte lumps in it. It looks like powdered sugar, but I had sifted it prior to use. There was salt in the recipe. Could it be the salt causing this?

I too have this problem. I noticed that when kneading the longer I knead the less lumps I have. Usually there will be a couple left that I can just pick out. When I am kneading they come to the surface and I can get rid of them that way too. I just do the easy mmf recipe so I am not sure about the salt. My lumps are just powdered sugar.

Could it be some of the gumpaste had dried? Gumpaste dries very fast around the edges and it wouldn't take much too cause little bumps in the mixture.

Thanks for thinking about the gumpaste drying faster. I never thought of that. I know that if you knead the gumpast you can bring it back (to a certain point). I'll have to try kneading the gumpaste to a really smooth consistency before incorporating it in with the fondant. THANKS!

Did you allow it to sit a day before using it? I find that the next day the sugar lumps seem to dissolve but if I try to use it right away after mixing I see lumps.

Yes, I do let it set for at least 1 day. Do you refrigerate the MMF. If not how long will it last?

If I have any left over I refrigerate it, but my business kitchen is in my basement so it's cool down there. I make it, wrap it really well and leave it on the counter (which is stainless, so it's coldl). The next day I just knead it again until it's the smoothness/temp. that I need it to be to work with.