Here is some information on thickening foods and what you need to keep in mind for storage.
Roux: Most common thickeners for savory sauces. This mixture of flour and fats are blended gently over low heat for 5 minutes to a much longer period depending on how much time you have and patience. There are three kinds, white, blonde or brown. White roux should not color; blonde barely; and brown should reach the color of hazelnut and smell deliciously baked. Unless a roux is cooked long enough to dispel the raw taste of flour, this unpleasant flavor will dominate the strongest stocks and seasonings. Because of lack of refrigeration you may have to use right away.
Browned Flour: This is a slow but inexpensive way to make a gravy or sauce. Place 1 cup flour in a heavy dry skillet. Stir constantly over low direct heat until golden brown, about 30 minutes. Stir frequently, scraping the flour from the sides and bottom of pan. Do not let it get to brown or, as with brown roux, it will become bitter and lose it’s thicken power altogether. Even properly browned flour has only about ½ the thickening power for all-purpose flour. It may be stored in a tightly covered jar in a cool place.
Flour Paste: This is usually used to thicken gravy and sauces in emergencies. The results are never palatable as when even a quick roux is used. Make a paste of flour and cold water or stock. Use about 2 parts water and one part flour. Stir as much of the paste as needed into the boiling stock or drippings. Permit the sauce to heat until it thickens and simmer for at least 3 minutes more to reduce the raw taste of the flour. Stir frequently with a wire whip.
Cornstarch: cornstarch is used where translucency is desirable, as in Chinese or dessert sauces. Cornstarch should be mixed with a little cold water before adding to warm or hot liquid.
Blood: Blood from an animal or bird the sauce is a desirable thickener. You can save the blood from killing fresh game, (hare, rabbit or chicken) you may store it in refrigerated for a day or two, mixed with 1 or 2 tablespoons vinegar to prevent clotting. Strain it and add it to the sauce at the last minute just before serving swirling it in as you would butter. Simmer gently but never allow sauce to boil after the blood is added.
Reduction: This is another way to thicken sauces. If you intend to thicken a sauce by reducing it, season after you have brought it down to the right viscosity, otherwise you may have an over seasoned sauce or too salty.
Instant Potatoes: Can be used to thicken soups (if creamy), stews and casseroles. (I have even used in other soups, if your not heavy handed with it.)
Tapioca: Can be used for thicken desserts like pies or cobblers. (My favorite)