i made gravy yesterday with a little of the fat from a roasting pan with chicken roasting, and the broth from boiling the gizzard, etc. the gravy is now refrigerated. i'm going to make more gravy tonight with the rest of the fat that is left in the roasting pan and and some broth i'll make with a mix. can i mix the 2 gravies together, or will there be a consistency issue? if so, should i make the new gravy first and add the original to it, or start with the first gravy and add to it?