When stock is used in recipes, it is almost never used as the sole ingredient in a dish.
Stock becomes a solid cooking platform in most dishes, or the flavour support in many dishes like risottos and casseroles. Stock can also be added to dishes in the place of cream, milk or even water to add liquid and flavour.
A very common way of stretching the cooking capabilities of stock is to thicken the stock with a starch, either flour or a cornstarch.
First, there is some terminology we need to explain. What is a part? A part is simply referring to equal quantities of ingredients, in this case flour and butter. Here is an example.
1 equal quantity of flour (10 grams) to one equal quantity of butter (10 grams), or 1 part of flour to 1 part of butter. This quantity is a good starting point to thicken any dish, then you can always add more if required.
Here are three different ways to thicken your stock:
Roux – is a cooked mixture of flour and butter normally made with 3 parts of flour to 2 parts of butter. Melt the butter in a saucepan, then add the flour and cook on a medium heat until it looks like pastry dough. You can add this mixture to dishes like soups, pie fillings and sauces like gravies to thicken them up. You should add 1 part roux to 10 parts of liquid in the dish you are thickening.
Beurre manie – literally meaning “Kneaded Butter “ is an easy way of thickening small sauces but also a nice way of enriching the sauce. Beurre Maine is 1 part of flour and 1 part of butter kneaded together. You should add 1 part of Buerre Manie to 1 cup of liquid in the dish you are thickening.
Slurry – this is the easiest way of thickening sauces in a hurry, but this method does not add any extra flavour to the dish, a corn flour and water slurry mixture is ideal for last minute fix ups to sauces or stews. Slurry is 1 part corn flour to 1 part of water or stock mixed together. Then add 1 tablespoon of slurry to thicken 1 cup of liquid.