The heat from the chocolate eventually weakens the candy shell, causing it to crack. If you noticed that certain colors of M&M’s cracked sooner than others did, it may be because the food coloring used in those colors created a weaker candy shell.Now let’s think back to the procedure. A package of M&Ms (If possible, get a package of coconut M&Ms. 2  This package will have three colors: green, brown, and white. 3  If this isn’t possible, get the good old traditional M&Ms with five colors: yellow, red, blue, green, and orange.).