What chefs use to make gravy are pan drippings from roasted meats, a thickener such as a roux, which is a mixture of fat and flour or a flour/slurry and stock or broth to add liquid and flavor.
Chefs also use key flavor enhancers to make gravy which include mirepoix, which is onions, carrots and celery, herbs such as rosemary and thyme and ingredients such as Marmite or soy sauce to add umami and depth.
What chefs use to thicken gravy is a roux, which is a mixture of fat and flour and other thickening agents like a cornstarch slurry, which is cornstarch mixed with cold water.
Some chefs and restaurants also thicken gravy by using other starches like arrowroot starch or potato starch, or by adding pureed vegetables or nuts or simmering the gravy longer which reduces the liquid in the gravy.
Common gravy thickening mistakes are adding thickeners to a cold or lukewarm sauce, not simmering long enough for proper thickening and adding too much thickener or liquid.
These common gravy thickening mistakes can cause lumps and also a paste like texture.
Other common gravy thickening mistakes are overcooking the gravy which can result in a gummy and overly dense consistency, and cooling can make a pourable gravy too thick.
Gravy thickens as it cools, so a gravy which seems perfectly and easily pourable when it's hot can get to thick as it cools down.
Simmering the gravy too long can reduce the liquid too much and result in a thick and sticky gravy and too much thickener in the gravy can result in a heavy and dense or paste like consistency.
Adding roux to your gravy also makes it thicker and makes it taste better as well.
A roux is a mixture of some flour and fat such as butter or bacon grease and is commonly used in making good gravy.
The amount of roux for 4 cups of gravy is 1/2 cup or 8 tablespoons of fat and 1/2 cup or 8 tablespoons of flour, so that the roux can achieve a heavy bodied consistency with 4 cups of liquid.
You can use butter for the fat or even animal fats like bacon grease, bacon grease makes the roux much better and the resulting gravy or dish taste better as well.
The 1/2 cup or 8 tablespoons of fat and 1/2 cup or 8 tablespoons of flour ration provides 2 tablespoons of fat and 2 tablespoons of flour for each cup of liquid and is a common starting point when making thick gravy.
A roux is made from equal parts of flour and fat and it goes by weight.
The equal parts of flour and fat that are used to make roux are measured by weight.
The roux is made by mixing equal parts of fat and equal parts of flour and then the flour and fat are mixed together and cooked together to form a paste which acts as a thickening agent for gravy, sauces, soups etc.
Common fats that are used when making roux are butter, vegetable oil and animal fats like bacon grease or even a combination of these fats.
The cooking time for the roux will also determine the roux's color and flavor, which can range from dark brown to a light blonde color.
The longer the roux is cooked, the darker the roux becomes, changing it's flavor from neutral to nutty and rich and losing some of it's thickening power.
When the flour is cooked in fat, the fat coats the starch granules and prevents lumps when the roux is added to liquid, which results in a smooth and thick sauce.
The cooking process also eliminates the taste of raw flour and creates a nutty or smoky flavor.
The point of a roux is to use it as thickening agent and flavor base for dishes like gravies, sauces, stews and soups.
The best flour for a roux is all purpose flour because it's readily available and works well in roux.
You can also use other white wheat flours, such as bread flour or cake flour, cake flour is high in starch and less gluten.
You should also not use self rising flour as it contains leavening agents which can scorch and for gluten free flour options for roux you can use a high quality, finely milled all purpose flour.