In the United States, depending on where you are, gravy can refer to a couple of different things. In the South it can mean a sauce made from sausage drippings, flour, and milk that is often poured over flaky buttermilk biscuits. If you are Italian-American, gravy (or Sunday gravy) might be the huge pot of tomato based ragù made on weekends for a big family gathering.
For this story we are looking at the more widespread understanding of gravy. That is to say, the thick, savory sauce that frequently accompanies a nice roast, whether it is roast turkey, roast chicken, roast beef, or more.
Gravy is usually made with a bit of stock and the lovely bits that stick to the roasting pan, herbs, and salt and pepper. The mixture is thickened with flour, and perhaps a bit of butter is added in the end for some nice richness.
Like gravy, jus (pronounced zhoo) starts with the drippings from cooked meat. Unlike gravy, however, it is not thickened with flour; instead, the liquid is reduced until it reaches the desired consistency, which is usually thinner than gravy. Obviously it takes longer to reduce liquid to a silky, viscous consistency — that’s one reason you tend to see jus on menus more often than at your friend’s house accompanying the roast chicken.
So there you have it, jus is a reduction and gravy relies on a thickening agent. Both, however are delicious and pair fabulously with the only roast chicken recipes you’ll ever need.