OXO Good Grips Small Fat Separator Cup 5 "Excellent results" Kirsty 23 July 2014 The idea of the stopper in the spout, is that you put this in prior to pouring your mix into the jug. It keeps the spout full of air so the mix does not rise up the spout until you are ready. You wait a few minutes and watch the fat rise, and once ready you remove the stopper and the fatless gravy immediately enters the spout. Strainer at the top picks up garlic, skin - anything that might get caught in the long spout. You could use without the stopper, but if you do the first serving of gravy would have fat on the top as collected in the spout. All the taste without the fat!