I whipped my egg whites and sugar for my SMBC till it reached the appropriate temp. It was very fluffy. It was my third double batch today and I have no sugar left and stores are all closed. My SMBC is grainy. Does anyone out there have a fix for this

I don,t know why it would be grainy. You place your whites and sugar over a double boiler and whisk till it reaches 140-160 degrees on thermometer. This melts all the sugar. Then you beat these whites and sugar until the bowl is cool, around 10-15 minutes. Then you add the butter and then the flavoring. Is this what you did. I always feel the mixture in the double boiler to be sure the sugar has melted before i beat it in the mixer. I don,t know how to correct it now. I will help you try to find that answer.

Thanks for the response, I'm afraid I had to ice the cake with it. Time is running out for me. I did everything as you said I even tested it by rubbing it between my fingers. It didn't feel grainy. But when it was finished it was so bad you could see it when I iced the cake. Its for my grandaughter's confirmation so its not like I have a paying customer but I always strive for perfection and this is a big disappointment for me.

You might have "cooked" the eggs too much. I saw this happening to someone once. Tiny white specks all over her SMBC.