There are a couple of things you can do. Definitely agree with arrowroot and I also use tapioca flour. Depending on what I'm working with and the colour of what the actual finished product will be, I'll steam veg and puree with a bit of the liquid that I'm using and then incorporate the two. Like, if I'm doing something lighter I'll keep to potato, mushroom, onion/garlic for the thickener with a little white wine. Darker I'll still use potato and such but will incorporate carrots, etc., a little red wine. Cream can go into either if that's something you want to play with. Basically keeping a food colour wheel so I don't get gray or lavender sauce.
Beurre Blanc is fantastic and definitely something to remember as an alternative. Good on all proteins and veg. This is a good recipe.
I use arrowroot powder instead of flour to make a rue.
Just do a reduction. Add some water to your dripping and simmer it until the consistency is as you like, usually a half hour or so. Add some butter to it too. If you want, you can blend cooked veggies or potatoes (if you eat them) with the drippings. Lastly, you can always add potato flour or tapioca flour if you're not metabolically deranged and can tolerate a starch load.
When we roast a chicken, it's always on a bed of veggies. We take some of the drippings along with some well-cooked veggies from the bottom of the pan, (usually onions, garlic, squash, carrots, parsnips), transfer to a sauce pan, add some chicken bone broth (from the last roasted chicken!) and puree with a stick blender. Add salt/pepper/other spices to taste. Works pretty well.
the recipe below is from 'elana's pantry' and i like it because it thickens with pureed onions and garlic as opposed to any sort of flour or gum.
Herb Gravy 1 quart chicken stock 2 medium onions, coarsely chopped 2 cloves garlic pan drippings (from roasted chicken or turkey) ½ teaspoon celtic sea salt 1 tablespoon thyme, chopped
1.In a medium saucepan, heat chicken stock, onions and garlic to a boil 2.Reduce heat and simmer until onions and garlic are soft, about 30 minutes 3.Pour pan drippings into saucepan 4.Blend stock-onion-drippings mixture in a Vitamix until smooth 5.Place mixture back in saucepan and reheat, then season with salt and thyme 6.Serve over turkey, mashed cauliflower, or anything else
If your stock has good gelatin content (and it should!) reduction will get it thick but you will need to really boil it down. For starchless demiglace, you would need to reduce a gallon of stock down to a few cups.
The most flavorful way is to puree the vegetables from the stock or pot roast or whatever you're making and add them back to the stock. Sautee'd carrots, onions, and celery are the cornerstone of flavor in classical cooking. This won't get you the silkiness of a starch thickened sauce but it will get you close. Monter au buerre (stirring in butter at the very end off heat) will help.
I don't care if my gravy is super-super thick, so this is what I do:
Pan drippings from a roast chicken
squeeze juice from half a lemon
a little chicken stock from the last roast chicken
salt/pepper to taste
a "pat" of butter (clarified last time, since I'm doing Whole 30)
arrowroot to thicken
bring to a boil to reduce
i make a paleo gravy without milk or flour. i use pan drippings . i add water to deglaze the pan add an egg yoke as a milk substitute and butternut squash for the flour substitute. then i blend it together with a stick blender till silky smooth. i cant believe how it fools the mouth into thinking its a cream gravy.
Agar Agar is a seaweed that thickens nicely, I use that, but agree that if you just reduce it, you have no need thicken.
puree cauliflower instead of using flour
Here's a recipe for no-flour pot roast gravy from Fast Paleo. It should be a straightforward substitution of turkey juices to make turkey gravy. Note: depending on your turkey and/or how many you're having for dinner, you may not have enough liquid from the pan drippings alone. If so, you'll either want to have some stock on hand or make giblet stock ahead of time with the neck & giblets that come with your turkey.