Chef Jacob,
I've made chicken stock from scratch numerous times. I've recently started using your suggestion ( I believe it was in the Thanksgiving series of podcast) to skim off the fat and use it to make a roux. So my workflow is to make the stock one day and put in frig overnight. The next day, skim the fat from the surface. (which is somewhat thick)
So the first time I did it, I removed the fat and cook on medium heat to evaporate the water. I realized I had a layer of particles (stuff) on the bottom of the pot which started to burn. I quickly removed it and strained through paper towel. Luckily, I caught it just in time not to affect the flavor. So the next time, I thought to just heat the fat until it was liquidified, then strain it through paper towel before starting the cooking process. (guessing that the particles is what was burning the first time). To start the cooking process, I put it back into a clean pot and cook it on medium until the water was gone. This time, there was a slight burnt ring on the pot at the liquid level and other burnt bits.. I strained it again and used the fat to make a dark roux for gumbo. For sure, I didn't burn the roux and the roux smelled fine. Nutty and delicious actually. So I made the gumbo but it does have a slight burnt taste to it that both my wife I dectected.
Hope that all makes sense.
Am I straining it wrong? (fine mesh strainer lined with about 2-4 layer of paper towel)
Cooking too long? (the sound of the moisture popping is fairly reduced from when it starts but still present.) The fat is getting dark but not as dark as yours look on the video.
Any other ideas / suggestions?