Something went wrong when I made my jus, I don't know what. And it is something I've noticed the past several times I've made it. My gravy or jus comes out bitter. I start off by sweating onions and garlic in some olive oil and add dried thyme. Let that go until softened. Then I add a couple of Tbsp of soysauce and a tsp of worchestershire to deglaze. Then I add my home-made beef stock and let it reduce by a third. Season and taste and then I add the drippings, turn off the heat and a pat of butter. It tastes very good, but bitter. Where am I going wrong? For gravy I usually add the flour after the onions sweat a while but before I add the liquids.