...Gravy Boat that is.
A roux is a mixture of four and fat, usually butter or perhaps the fat from the protein you just cooked which thickens a sauce and can flavor it as well. You heat the fat and whisk in the flour until it becomes one over a moderate heat, just be sure not to burn the flour. As you stir it will change color and brown to a blond roux, and if you continue it becomes a peanut butter color and darker and darker. It depends on what you are using it for and what you are trying to accomplish in deciding when it's the right color. Think etouffee, gumbo and french "mother" sauces, they usually all use it. Those mother sauces are a sauce in themselves and a base for other sauces. Make a roux, add milk and you have a béchamel sauce...now add cheese and you have a mornay sauce as I explained here.
So, you can use a roux to thicken a sauce or you can use corn starch. Mix corn starch 1:1 with a cold liquid in a side bowl into a slurry. Some use 2:1, liquid over corn starch. Water works fine...I have also used wine and stock or broth, it just depends how you want it. However, by using a corn starch slurry, the liquid you are adding it to must be quite hot or it wont thicken properly. "So why can't I use that same method with flour, Mr. Blogger Man?" Well, Billy...you need to cook the flour and water solution to remove the raw flour taste...and didn't I tell you to stay out the kitchen?
There are many other methods to thicken a sauce. Arrowroot is one. Flour tends to make your gravy a bit cloudy which may be fine with you, corn starch a little less cloudy...but arrowroot will keep it clear and shiny. Use it the same as corn starch. Some say arrowroot makes meat sauces look fake and weird and does not re-heat well and will make dairy based sauces slimy. Tapioca is also popular, there's potato starch and whole bunch of other strange stuff to use.
Because I will tryout the Traeger smoker /grill for the bird, I wont be using a roasting pan in the oven and catching all the wonderful yum-yums on the bottom of the pan for the gravy, I will need to use alternative #2 which I have used for the rotisserie method. That is to get some turkey wings and veggies and roast them up the weekend before...and start making my gravy ahead of time. How great is that!
Roasted up some turkey wings with a splash of olive oil and S & P, about 1/2 hour at 375.
Toss some aromatics in a big pot...an onion, 2 celery ribs, 4 carrots, which will help by also coloring the stock, fresh parsley, sage, rosemary and thyme...they should make a song like that...a few peppercorns and head of garlic cut around it's equator. Some S & P. Stir them around in EVOO until they start to caramelize. No need to peel the onions and such as this will all be strained.
The toss in the wings and pan juices, deglaze the roasting pan as well to get the goodies that stuck, then cover with cold water...simmer for about 2 hours. I will make the roux and finish the gravy on turkey day.
If you are doing this to make and save for later, a cleaver way to do this is to pour 1 cup of the strained stock into a muffin tin and carefully set level in your freezer. Once frozen, warm the bottom a bit to loosen each one and toss in a freezer bag. You now have convenient, homemade stock at the ready in 1 cup portions.