Tallow Question in Kamado Cooking and Discussion Posted July 30 I rendered down fat from a brisket trimming back in April. I cut the fat into little pieces and put them in boiling water (or simmering… I forget) for hours until it was mostly rendered down. Then ran through a fat separator to separate little pieces of meat, and poured the fat into a mason jar. It looked great at first, but now looks like this (pic attached) - is it still usable? Does it just need to be mixed, or is part of it (or the whole thing) bad?